What is the resolution on these sediments? How far forward in the recent past can you reliably go? The point of the question being… can you say with confidence that the last time the Antarctic coast achieved these temperatures was 15.7 Mya, or is it possible that the same conditions occurred more recently, but the sediment proxy is only valid from X Mya and back?
[With the ultimate point being “can we reliably treat the sediments as evidence that these conditions have not existed in 15 Myr, in which case it is quite possible that global warming somewhere over 2.5˚C will (in time) restore a condition that has not occurred on Earth since then?”]
2nd paragraph reads “11C (20F)”; something isn’t right there…
And now for a question: do we know the atmospheric CO2 at that time?
[Response: A change of 11ºC is the same as a change of ~20ºF (19.8 to be exact). Miocene CO2 is surprisingly difficult to pin down – Two relatively recent papers come to quite different conclusions: Tripati et al (2009) say ~400ppmv and Pagani et al (2005) say ~280ppmv (based on quite different techniques). This is discussed in the Ruddiman paper linked above as well. – gavin]
[Response: Actually, I don’t think Miocene CO2 is particularly harder than any other time before we have CO2 from ice cores. All the geochemical proxies have similar problems and uncertainties. The Miocene CO2 problem stands out because the CO2 estimates bump up against values so low it’s hard for known climate physics to explain how warm the climate is. That’s particularly true if Pagani’s value is closer to the truth, but even the higher value in Tripati et al is problematic. Thus, it is particularly important to understand more about the nature of Miocene climate, and ANDRILL is part of that process. Puzzles like this are Nature’s way of reminding us when there is potentially some big gap in our understanding, and such puzzles demand to be resolved. Sometimes, the puzzle is resolved in favor of the models, through continued improvement in the proxies; this happened with the earlier puzzle of relatively warm CLIMAP LGM tropical sea surface temperatures. To some extent, the problem of cool Eocene tropical temperatures was also resolved in favor of models, though the story is still not complete there. But it could also be that the Miocene and Pliocene are telling us that the climate has some as-yet unfathomed way of flipping into a warmer state. Danger ahead? Best not to poke the angry beast. – raypierre]
Bob, this is one of the first reports out of the ANDRILL program — worth looking at how it’s being done. I’ve been waiting eagerly for anything for quite a while, knowing it was coming eventually.
ANDRILL pulled up cores from various sites, put them on ships and sent the material off to research labs all over the world where the cores went into storage or labs. People are working to make sense of the chunks they have, write that up, and get it to a journal. Lots of pieces, widely distributed.
I doubt there’s an overall complete answer to your questions possible until that work is well advanced.
If I knew where to send donations, I’d send them money. It’s quite a project.
Yes, re-read at least once, carefully, in context, those temp references are clear, but maybe it’d be a lot clearer if science quit coddling Americans and instead force them to start thinking in the terms science and the rest of the world does, skip the F translations and it doesn’t bring the thought process to a bump that requires re-reading, or result in misinterpretations. ;)
Response to 1 and 3: This is not really ‘one of the first reports out of ANDRILL’ – there have been many papers out of that program already, quite a few fascinating. see e.g. ‘Modelling West Antarctic ice sheet growth and collapse through the past five million years’, http://www.nature.com/nature/journal/v458/n7236/full/nature07809.html; and ‘Obliquity-paced Pliocene West Antarctic ice sheet oscillations’, http://www.nature.com/nature/journal/v458/n7236/abs/nature07867.html, published in 2008 and 2009. The ANDRILL website gives great information on the project (http://www.andrill.org), with lots of information on project-related publications for professional scientists and the general public.
And yes, the proxy can be used from the present into periods going back many millions of years as long as the right type of sediments is present; methods can (and have been) used on deep-sea cores recovered by the Integrated Ocean Drilling Program, i.e. from other parts of the worlds oceans and from sediments on land.
flxible wrote: “… if science quit coddling Americans and instead force them to start thinking in the terms science and the rest of the world does …”
Yes, by all means let’s “force” Americans to start thinking in terms of Centigrade instead of the Fahrenheit scale with which they are intuitively and viscerally familiar. It’s important to show them the smaller Centigrade numbers, so they won’t immediately “get” just how high these temperatures we are talking about really are. It is much more important to get them to use the “correct” temperature scale than to effectively convey the magnitude of the problem in terms that they can readily understand.
Hank, thanks. It’s interesting that this is also on the heels of the Lake El’gygytgyn paper, which seems to be similar in many ways. I actually had the same question in that case, but I could tell from the paper itself that the proxies went back at least as recently as the 10,000 ya.
I’ll have to see if I can beg/borrow a copy of the paper from someone.
[Response: Actually there is great story (or three) to be told about the ‘Lake E’ results. The difficulties in getting that core are not widely appreciated! – gavin]
SA – I’m aware of the problem you point out, being an American by birth and a Canadian by choice, but is 20F or 45F going to raise any uneducated American eyebrows? Might sound real nice to a Texan about now. And the “instant translation” is no doubt what tripped LH above. Maybe there could be “popularized translations” into “American” where all stated temperatures were in F? Someday the US will finally generally adopt the C scale, but reading papers with both scales included does disrupt the smoothness of my [and others] thought processes – maybe because I understand both.
I know I’m just a dumb American, but I’m perfectly fluent in both centigrade and Fahrenheit, and I can even get along in Kelvin or Rankine if necessary. It’s a pity the rest of the world is so easily confused by the mere suggestion of an alternate temerature scale.
What was the obliquity? Seems like with no tilt, then it doesn’t really matter what the inferred CO2 was is, it’s not causitive but reactive? And no, CO2 could/will not be a forcing on the scale of obliquity (as the precautionary principle seem to lead many here to believe, not speaking of you directly as the article author)?
Perhaps it would be useful to add that this study is consistent with both deep sea records from around Antarctica (Shevenell et al., 2004 among others) as well as terrestrial records from the Dry Valleys (Lewis et al., 2008). So now we have evidence from different proxies, phases (biogenic carbonates to organic biomarkers to pollen assemblage data), and sediments from different environments (terrestrial to marine) that all show a consistent pattern of climate change in the Pacific Sector of the Southern Ocean and Antarctica during the middle Miocene climate optimum. It is now important for us to determine if this response was similar around Antarctica.
While Middle Miocene CO2 levels need (require) more study, it is important to remember that other forcings and/or feedbacks may also be important.
The ANDRILL record (this study, and the program in generally) is extremely important because it is a proximal marine record that links the terrestrial and deep sea records. We are finally able to recover high quality marine sediments from the Antarctic continental margin that are giving us important opportunities to integrate climate proximal to Antarctica’s ice sheets with detailed records from deep sea sediments from lower latitudes. This is one of MANY high quality studies that have come or are coming out of the ANDRILL program.
To the person who wanted to donate money, contact the ANDRILL program at the University of Nebraska… Alternatively, as a new Assistant Professor, I am currently accepting donations from unconventional sources. Government funds are getting harder to come by these days :)
I would like to point out a correction to the false-color map of Antarctica accompanying the post headline. Siple Dome is presented on the wrong side of the Ross Ice Shelf, it should be marked on the “grid west” side, in the general vicinity of Byrd and WAIS camps.
The dot currently marked “Siple” looks closer to CTAM/Beardmore.
Just a minor comment on an excellent, informative post! Thanks.
[Response: Oops. You are indeed correct. The map came from the article SI, and so someone else will need to fix it (I’ll let them know). In the meantime, I’ll swap in a more correct map… Thanks – gavin]
Amelia: Alternatively, as a new Assistant Professor, I am currently accepting donations from unconventional sources. Government funds are getting harder to come by these days.
If you have not already, consider RocketHub. I just ran into another project that was doing fundraising there and had stellar results; astonishing how much money is laying about idle in the pockets of bystander enthusiasts.
One interesting response of the Miocene biosphere to the thermal stress was the contraction of the equatorial biome to the few plants that could take the heat- in Borneo and Sumatra it reverted into the cycad monotreme that fossilized into the ultraslow sulfur coal strata mined today.
Thanks for this fascinating post on the methodology behind your findings.
What’s really interesting about the warm climates prior to the ice core record (but not too far back….following say, the Eocene-Oligocene transition) is that it probably provides a good template for the long term tail in the future of the Anthropocene (in the absence of geo-engineering strategies). I have in mind the century to millennial timescale response to unabated CO2 emissions.
Substantial evidence exists that the peak warming should increase linearly with our CO2 emissions, peaking at ~2 C per trillion tons carbon emitted, but with global temperature “locked” into that new state even as emissions go to zero. Concerning the longer-term feedbacks, what’s really important for the type of “concentration thresholds” (e.g., 350 ppm, 450 ppm) that some people have proposed is that those concentrations remain elevated above the threshold of choice for thousands of years. Some of these “CO2 targets” are largely based on the threshold CO2 values that were required to initiate Antarctic glaciation.
Another thing to keep in mind is that the Miocene and Pliocene may provide evidence for multiple equilibria in the climate system. The presence of “small but hidden bifurcations” would be extremely interesting. Despite the proxy uncertainty, CO2 values were probably maintained below 700-800 ppm during the entire time period discussed here up until the present. This is true for CO2 proxies based on Boron, stomata, phytoplankton, and others. Plate tectonics is not too different and solar irradiance was not radiatively distinguishable from present-day values. Because of the logarithmic relationship between CO2 concentration and its impact on outgoing radiation, it’s difficult to argue that these fundamental boundary conditions conspired to produce much more than a modern-day equivalent of a doubling of CO2. Yet the climate was much different. Not only is global mean temperature in excess of modern by many degrees, but sea level is much higher (+10-30 m, at least in the Pliocene) implying substantially less ice cover, the meridional temperature gradient is suppressed, and the dynamics is different than today (e.g., a “permanent El Nino like” zonal SST pattern in the Pliocene).
To the extent that multiple states exist, it is very unlikely that the same CO2 threshold that initiated Antarctic glaciation would be the same as the threshold going the other way.
A lot of this seems way out there in terms of timescale, but just think if the Vikings decided to engage in some sort of activity that put us on a climate branch like the Pliocene or Miocene.
To enlarge on the Colose comment–the paleoclimate record shows that the earth can maintain a warmer equilibrium for millions of years, but we don’t understand how the feedbacks rearrange themselves. The Pliocene is more familiar because it behaves like what we would expect from mildly higher greenhouse gases maintained for a long period. The Miocene is uncomfortable because it appears unstable. But, the warm temperatures lasted for multiple millions of years, in addition to even warmer intervals.
The answer is I’m just an idiot who was reading this while doing other work. It’s like speaking a foreign language – if I truly understand Spanish, I don’t convert it to English in my head. I’m fine with the metric system, so if you tell me 67 kilometers I just know how far that is; I don’t try to convert it to miles. But telling me Celsius is like telling me a word that I convert to English in my head, leaving me open to screw up.
Something to keep in mind is that priot to about 4 mya there was a near-equatorial seaway connecting the Pacific and Atlantic oceans. That alone would result in a quite different climate I should think.
Comment by David B. Benson — 12 Jul 2012 @ 7:56 PM
This is all the more interesting because of C4 carbon fixation in plants. There’s some thought that relatively low available CO2 was instrumental in the evolution of C4 carbon fixation, but it’s hardly settled, especially because the C4 pathway evolved independently in different families of plants.
“C4 plants arose around 25 to 32 million years ago during the Oligocene (precisely when is difficult to determine) and did not become ecologically significant until around 6 to 7 million years ago, in the Miocene Period.…Today, C4 plants represent about 5% of Earth’s plant biomass and 3% of its known plant species. Despite this scarcity, they account for about 30% of terrestrial carbon fixation.”
A summer temperature of 7C along the coast of Antarctica: does that not say that the Antarctic ice sheets were very much present? Greenland gets warm along the coast, too, and the ice is present still: could not the increased humidity make the center of the Antarctic land mass have thicker ice than now?
Was ice rafting of fines obvious or obviously absent?
If temperatures were higher with less ice I understand that sea levels would be increased as we have defined under our current global warming scenarios. In this case the Antarctic Coast would have a completely different profile than today.
Does this work give any insights to the mechanisms of the process of sea level changes?
Having read the article my curiosity was sparked by the statement that the sediments were 400m below sea level. Therefore I’m understanding that sea level dropped with cooling and the formation of ice.
This appears to go against the prediction of our models which predict the opposite effect.
I must be missing something basic here. Any thoughts welcome.
Let me see if I can oversimplify here off the top of my head, a common source for such stuff — and perhaps the scientists will be kind enough to laugh and correct my errors.
So start off with an ice free Antarctica — there’s a bunch of large islands and rivers from them drain into the ocean between them and around them. Eventually something changes — the continental drift moves the whole area toward the South Pole, the Earth’s orbit and inclination vary a tiny bit, the area starts to snow more and more, and the ocean between the islands starts to freeze over longer. Eventually the ocean surface stays frozen and the snow starts to build up year after year. After a while the ice gets so thick that, as its own weight builds up, the mass of floating ice pushes downward.
First it pushes the water under it out toward the edges, wherever it can escape; eventually the ice and the water under it start compressing whatever was there into mud and squeezing the mud along with the water out toward the edges of the ice cap. Out at the edges where the ice isn’t as thick, whatever’s being squozen extrudes and spreads out into a river delta at the level of the seabed.
As the ice cap builds larger and wider the ice in contact with the rock advances in all directions toward the edge, grinding and scraping in some places. The bottom of the ice and the water and sediment pushing out ahead of it carve up the seabed.
Then things warm up a bit; the ice retreats along the sea floor, some of it melts from below in the ocean leaving a surface sheet of ice. Whatever likes living in the ocean gets into that water under the ice, some of it dies, and you get a sediment layer full of shells and droppings and whatnot — living organisms make much of that sediment.
Then things warm more, the surface floating ice clears off intermittently at least, and you get an ocean making a sediment layer full of stuff hhat lives along the edge of forming or melting ice, or in blooms during springtime, and also all the organisms that live off of what blooms in the spring there. Different kind of sediment layer.
Then at some point it gets colder longer; there’s more pressure on the ice cap, more mud squeezed out, more ice in contact with the rock pressing out toward the edge. Surface ice stays longer, different kind of sediment layer forms.
Every now and then a slope fails and a mass of muddy water — a “turbidity current” — takes off downslope tearing away and rearranging everything for a great distance, recarving the surface. (One measure of these was when one happened recently and a series of ocean telecommunication cables got broken by it, one after another, over a very long distance.)
Thanks again for the reply Hank. Food for thought.
If, as you show, Antarctica is in the same place then the climate must have been very different from what we have today.
In my early education we were taught a theory that the earth had a canopy of water vapor which had the effect of keeping the whole earth in a warm balance. At some point the canopy collapsed and the vapor turned to water and filled the oceans.
This kind of fits as it means the plants would have been in abundance and the seal level lower. Would this theory hold any water? Please excuse the pun!!
My question was; “can this theory hold any water” when considering these latest discoveries. It does seem to fit very well.
Reading through some of your links it appears to be an open question. The last time I heard about it was from a park guide at Muir Woods in California (home of the giant Redwoods) who gave a very compelling talk on the likelihood of this climate model. Pity it gets negatively linked to Creationism and therefore easily dismissed in many folks minds.
Titus @42 — Water vapor is (almost) entirely controlled by temperature. The evaporated H2O fairly rapidly condenses out as precipitation.
In the distant past there was more CO2 in the atmosphere than at any time up to a few years ago. The carbon cycle is not well understood, at least by me, but it is clear that CO2 levels have been gradually decreasing, on average, for the past 50+ million years. This is thought to be related to the formation of the Himalayan mountains starting at that time.
Comment by David B. Benson — 15 Jul 2012 @ 5:07 PM
You need to find the book that part of your early education came from. See if it has been revised since you were taught that. Science works that way, and there will be much new and different compared to what youngsters were taught years ago.
If what’s taught today is no different that your early education, it’s not science.
Re 13 Matthew – YES! (Rankine is one up on me – although I understand how it’s constructed, I almost never see it.)
Re 14 thomas hine
– no tilt? Earth, so far as I know anyone knows, has always had significant tilt (maybe not Mars? If the Earth had no moon, the effects of the other planets would lead to wild obliquity variations over time. I suspect that’s not necessarily a general principle of large moons, though. I don’t know exactly what causes the obliquity variability in detail, but in general, precession (that component not caused by the shift in the semimajor axis) is caused by tidal forces of mainly the moon and sun acting on Earth’s equatorial bulge. Since the Earth’s orbit about the sun and the moon’s orbit about the Earth are not coplanar, the moon and sun would independently cause the Earth’s axial wobble to be about different axes, leading to variations in tilt with respect to the other – however, the lunar orbit’s inclination responds to the sun’s tidal force (tidal relative to the Earth-moon barycenter) by wobbling about the same axis (perpendicular to the Earth’s orbital plane) that it causes Earth’s axis to wobble about. So in a rough time-averaged way the moon’s effect should be the same as the sun’s (in terms of direction). But there could be some terms that don’t cancel out when integrating effects over time, given the eccentricities of the orbits, etc(?). But then again, maybe it’s the other planets(?). Also, the Earth’s orbital inclination wobbles due to the other planets – I’d imagine this would affect obliquity in some way. Over geologic time, at perhaps varyind rates owing to continental drift and some other factors (Earth’s spin via coriolis effect’s role in Kelvin waves, and Earth-moon distance itself is very important), the dissipation of tidal energy combined with transfer of angular momentum has sent the moon farther from the Earth and caused the Earth’s spin to slow, which affects precession and obliquity cycles; I don’t know if there’s been any long term obliquity trend from that – maybe early on right after the moon formed? Any celestial mechanics out there to help clarify?
– Co2 not matter? Impossible! (tilt or not) – it absorbs and emits radiation in accordance with the Planck function, Kirchoff’s law (regarding thermal radiation) (most of the atmosphere is close to LTE via high rates of molecular collisions relative to other processes), and Schwarzchild’s equation (regarding optical path length, in case there’s another equation), with, for the absorption band most important in Earth-like conditions, optical cross section peaking near 15 microns and, averaging over individual lines, gaps, and wobbles, approximatly halving per some interval of the spectrum, so that each doubling effectively widens the bite that CO2 takes out of OLR by that amount (basically the same for net tropopause level upward LW flux and surface downward LW flux, although that’s not a bite but an addition – anyway it’s the change in tropopause level flux after stratospheric adjustment (equal to OLR change after stratospheric adjustment) that’s the most important for global average surface temperature because of the way convection can respond to radiative heating), causing an accumulation of energy until the OLR (via temperature increase – the Planck response) and solar heating return to rough time-averaged global balance, given whatever (non-Planck respons) feedbacks (lapse rate, water vapor, clouds, snow/ice, vegetation, etc.) occur.
– “not causitive but reactive?”
it’s both over various time scales; mainly causative over short time scales w/ respect to climate, but it must always react to something (like humans digging up and burning fossil fuels).
– “CO2 could/will not be a forcing on the scale of obliquity”
Who said it was? Although for modelling purposes, if you know how CO2 varied, you can enter it into a model as a forcing (academically, distinction between forcing and feedback can depend on your purposes or what question you are trying to answer or explain, etc.), or you can use climate + model to try to infer CO2 (+CH4, etc.) – generally, as long as you aren’t doing both for the same time period, it’s not circular, I think.
-“(as the precautionary principle seem to lead many here to believe,”
One has nothing to do with the other. Precaution pertains to action given uncertainty, it doesn’t eliminate that uncertainty.
Re 19 Russell – cycad monotreme – is that cycads with monotremes? (I find cycads interesting as I’m not sure offhand if I’ve ever seen one in person).
Re 25 Patrick – “the C4 pathway evolved independently in different families” I didn’t know that; thanks. I wonder about CAM now… (don’t need to reply, I’ll look it up when I get around to it).
Re 40/42 Titus – I heard of that water shell idea, and it was in the context of making a somewhat literal interp. of the Bible seem scientific.
But with an open mind and some fun with physics:
saturation water vapor pressure (w/ respect to a flat surface of pure liquid water) only depends on temperature, not total air pressure, hence the upper atmosphere above the tropopause could become very enriched with water vapor without having it condense (although this would be hard to maintain over a long time, I’d think (?)). Also a relative lack of CCN might allow supersaturation to some extent – I have no idea what extent (as it is, cloud formation can/does require some supersaturation – see ‘Kohler curve’, cloud droplet vs haze particle)
But outside CH4 oxidation, water generally comes from the ocean and works it’s way up through the troposphere into the stratosphere, with most being squeezed out along the way due to condensation such as when following a moist adiabatic ascent – hence water vapor concentration falls ‘precipitously’ with height up through the troposphere. Maybe H2O mixing ratio can increase with height in the stratosphere due to CH4 oxidation or due to localized injections from below that don’t have larger regional effects on the intervening layer (??). Falling space material can be a source.
But molecules bearing H can be broken up, given the energy of some shorter wavelengths of solar radiation, and the H can escape to space (at a rate that increases with the abundance of H-bearing species in the upper atmosphere – see “Biogenic Methane, Hydrogen Escape, and the Irreversible Oxidation of Early Earth” – Catling, et. al. – http://www.sciencemag.org/content/293/5531/839.abstract )
Also, consider that if you have too much column H2O in the upper atmosphere, the pressure necessarily increases (not adiabatically – heat can be radiated away given a little time) from it’s weight, and the first part of this speculation would fail to apply – it would condense out. A rough estimate of the maximum H2O you could store up there could be gotten by taking some representative temperature at the lower portion of where it would be and finding the equilibrium vapor pressure – the weight of the water can’t be greater than that.
And note that while the air isn’t circulated and mixed as vigorously up there as it is below, it does mover around – in particular, mechanical energy radiating as fluid waves transports some of the work output of the tropospheric heat engine upward where it runs an upper-atmospheric heat pump. There are the hemispheric meridionally-overturning Brewer-Dobson circulation and a global overturning above that which will replace much of the upper atmospheric air with air from below within … I don’t know the time period but it’s certainly not too long climatologically and short geologically. In fact, everything below roughly ~ 100 km height is called the ‘homosphere’ because of how well mixed it all is – except for things like water vapor and ozone, whose chemical/physical reactivity and associated concentrations of source and sink can stay a step ahead of mixing. Above the ‘turbopause’ is the heterosphere, where molecular diffusion dominates over turbulent mixing and the composition varies with height with each ‘species’ tending toward a seperate hydrostatic balance (perturbed by sources and sinks, I think).
Bringing it half-way back to the original topic, I read something a couple of years ago or so about the idea that (localized) glaciation can limit mountain height. I wonder if some higher mountain ranges prior the the Pleistocene might have increased atmospheric poleward heat transport via quasi-stationary waves.
see p.5/15 – if the moon-forming impact hadn’t occured, Earth’s spin may have been slower at first, but wouldn’t have slowed as much over geologic time and could be fast enough today to avoid wild obliquity changes. (A TV show on the subject of the Moon actually went so far as to specify how fast the Earth spun before the impact – I don’t have the notes in front of me but I think they said an 8 (?) hour day, which might have led to a 12 (?) hour day now, whereas after the moon forming impact it was a 6 (?) hour day and slowed to 24 hour day so far (evidence from tidal rhythmites suggests an 18 hour day something like 900 Ma – I don’t know the source for this)
So if the Earth spun fast enough we wouldn’t need the Moon to prevent such wild obliquity variations. I don’t know if/how adjusting other parts of the solar system could/would do the same.
Re 40/42 Titus
– A rough estimate of the maximum H2O you could store up there could be gotten by taking some representative temperature at the lower portion of where it would be and finding the equilibrium vapor pressure – the weight of the water can’t be greater than that.
– based on the assumption of 100 % H2O above that level. Adjust for differing conditions. more exact: calculate saturation vapor pressure as function of height (according to known or chosen temperature profile) and where it intersects atmospheric pressure – above is 100 % H2O and below the saturation vapor pressure is the partial pressure of water vapor (maximum allowable in equilibrium). Careful about summing amounts over height, because:
partial pressure, locally, is equal to total pressure * molar fraction
total pressure (in hydrostatic balance) is equal to the weight (mass*g) per unit area of overlying substance.
For example, with preindustrial CO2 around 280 ppmv, and being approximately well mixed in most of the atmosphere, the partial pressure of CO2 near sea level (absent local sources or sinks) would be approximately 0.28 mb (average sea level pressure is a little over 1000 mb, or 1 bar, or 100 kPa. 1013 mb is closer; it’s 1013.something mb). However, the mass of all the CO2 in the atmosphere contributes a larger amount to the total pressure because the molecular mass is greater than the average air molecule (from memory and by approximation, 44 g/mol / 29 g/mol * 280 ppm mol/mol * 1000 mb = 44/29 * 0.28 mb ~= 0.42(48) mb. H2O is the opposite; it’s molar mass is ~ 18 g/mol (and it’s molar fraction is highly variable, of course).
– where molecular diffusion dominates over turbulent mixing and the composition varies with height with each ‘species’ tending toward a seperate hydrostatic balance (perturbed by sources and sinks, I think).
Except perhaps charged particles. I don’t know a lot about that, but when mean free paths get long enough, the effect of the magnetic field starts to show; they locally follow helical paths. This happens to electrons below where it happens to ions, and in between the wind can move ions differently than electrons – this gives rise to the E-region dynamo.
Re my 45 re 14 – But there could be some terms that don’t cancel out when integrating effects over time, given the eccentricities of the orbits, etc(?) if I may indulge in tying up a loose end –
Interesting point – the rate of precession pulsates (or at least, it should given the physics – perhaps it is masked by Chandler wobble? – I don’t know) over short time periods. The tidal torque a mass raises on a planet via it’s equatorial bulge is maximum when the mass is overhead at ~ 45 deg latitude (assuming the shape of the planet deviates from spherical with a vertical displacement that is approximately sinusoidal over latitude, which I think is close to accurate, though am not 100 % sure – because I’ve never gone through the math including the amplifying graviational effects of the bulge itself) – it is zero if over the pole or in the equatorial plane. Aside from the effects of eccentricity, Solar-driven precession thus peaks at solstices and is zero at the equinoxes, and in general when obliquity itself is largest, and lunar driven precession relative to the lunar orbital plane (which can cause obliquity to change when not in the plane of Earth’s orbit) peaks when the moon is highest above or below the equatorial plane, and in general when the lunar orbit is tilted opposite the Earth’s tilt.
Meanwhile (if I’ve got this right) the planets collectively ought to cause Earth’s axis to tend to wobble about the angular momentum vector for all (other) planets (excluding intrinsic spins – equatorial bulges have gravity and Earth’s contributes to changes in the orbits of satellites, but for interplanetary interactions the effect should be second-order or less relative to positions, I’d think), and cause the Earth’s orbit (I picture it as a tidal torque on the Eart-Sun system (or Earth-Moon-Sun, actually, and it is the Earth-Moon system’s orbit about the sun) to wobble similarly (at a different rate, and this itself changes Earth’s obliquity independent of torques on the Earth), although ultimately all planetary orbits wobble about the angular momentum vector for all including themselves because those causing wobbles also wobble (but they don’t fall down!). And while total angular momentum is linearly proportional to masses and velocities and positions (though velocities do depend on positions differently), gravity is proportional to distance^-2 and linearized tidal acceleration to distance^-3 – and deviations from such a linear approximation get large when the distance is not so much larger than the dimensions of the system being torqued (and it’s interesting when the tide-producer is inside the system). So perhaps one way to describe it is that planets individually wobble somewhat about the whole but especially about the nearest neighbors, and larger and larger groupings ultimately wobble about the whole (?).
I think it best I just stick with Martin’s comment that “it’s complicated”!!!!!!
Just an add to my comment @42 about Californian Redwoods. When the sea fog rolls in which is does every day just now and covers all the coastal mountain ranges the Redwoods have their tops in the fog and they create condensation. If you stand under one it’s like a rain. This is what the guide was expalaining and how they could be one of the few surviors of a previous climate system.
This is about as far as my personal knowledge takes me………
I am not pushing anything one way or another, just that no one can satisfactorily explain them. Unless obliquity and seasonality are re-examined, I think it is absurd to start guessing about adaptations and hybernation when there is no evidence?
Re 53 thomas hine – if you know A better than you know B and the two are linked, you can use what you know about A to infer additional information about B; it would make less sense to make assumptions about B and push the conclusions on A.
Not that everything is known about climate history, but at least you can model climate to some extent with some confidence; you can model evolution to some extent (cost-benifit analyses) and certain patterns are expected, but…
It may be more of a stretch to suppose obliquity was much different than to suppose dinosaurs could hibernate (?) …
There is discussion about using knowledge of orbital cycles to date sedimentary records which have recorded the effects of those cycles. Variations in period are important here (and the obliquity and precession cycles are not true simple precisely repeating cycles – I think this goes for Milankovitch-type cycles in general. I saw a graph once which indicated precession cycles (including the effect of the shift in the semimajor axis of Earth’s orbit) skipped (or jumped?) a beat sometimes – if this happened at low minima in eccentricity, it seems to make some intuitive sense; if the eccentricity is near zero than it doesn’t take much change to the orbit to make the semimajor axis shift a lot. But I’m not a celestial mechanic.
“over a long time span, planetary orbits have chaotic behaviour, as was shown by Jacques Laskar in 1989; the error in the computation of planetary orbits is multiplied by 10 every 10 Myr. Thus, the Earth’s past orbit cannot be computed precisely (and used to calibrate paleoclimate data) beyond 100 Myr ago. However, extended computations beyond 100 Myr ago can still provide useful information.”
(While it isn’t clearly stated here what actually remains predictable for longer or not, I note that even a slight shift in the general character of a cycle can result in great timing mismatch over many cycles. It’s a little bit like climate vs weather, although a little bit different – the absolute timing of a cycle might be way off while the overall behavior looks about the same. Also, purely mathematically-speaking, amplitude variations needn’t be off for timing to be off – although be aware of nonlinearities in the sedimentary record responses.)
“Due to tidal dissipation in the Earth-Moon system, the Earth’s rotation is slowing down, and the Moon is receding at about 3.82 cm/yr. This induces a slow change in the obliquity. The team shows that this small effect induces a slow increase in the obliquity of about 2 degrees per billion years; but in the near future, as the Earth’s precession rate will cross a resonance, the obliquity will decrease about 0.4 degrees within a few millions of years, with some possible impact on the climate.”
The graph shows obliquity staying within 21.5 and 25 deg over nearly 500 Myr; 2 deg per billion years from ~ 23 deg now would get us to ~ 14 deg near the beginning (although I’m not sure this would remain near constant for that time, and was it even meant that way?)
It should be noted that Earth’s climate system response to orbital forcing may be to some extent dependent on relative forcing rather than absolute forcing – what I mean is: some (well, at least one) have argued that the dramatic (relative to ___) climate variations caused by slight variations in orbital parameters show how sensitively tuned everything has to be to support life, etc. But while the positive feedbacks of ice shee albedo and CO2, and others, can act on those timescales (with the Earth set up as it recently has been – there obviously have been times when such quasi-regular glaciations and deglaciations did not occur), there is a negative CO2 (via chemical weathering) feedback that is slower acting. (Setting aside to what extent life can adapt, etc.).
As it has recently been: http://en.wikipedia.org/wiki/Milankovitch_cycles
(Assuming it’s all correct) – Note, the “transition problem” does have at least one possible explanation: scouring away of looser material through successive glaciations eventually led to less lubrication of ice sheet flow, so ice sheets could get thicker, which changed their response to would-be deglacial forcing. See William F. Ruddiman’s “Earth’s Climate Past and Future” (a book, see also http://bcs.whfreeman.com/ruddiman/ )
I found some of these while looking for article(s) I found a few years ago that had paleotidal maps and graphs of changes in orbital cycles over geologic deep time. I never found them, although I did see paleotidal maps in some other places (just try googling paleotidal map).
47 David B said, “Jim Larsen @46 — Merely boiling hot methinks.”
It depends on whether you’re measuring at the beginning or end of the event. The way I understand it is that the surface was very hot but high up in the atmosphere it started to rain, with the rain vaporizing rapidly as it fell. Eventually the rain reached the surface and immediately vaporized, rose, cooled and rained again. Constant 24/7 rain and vaporizing pumped heat upwards, thus cooling the surface. Eventually, it got cool enough for the water to remain on the surface, so yes, at the end of the event it was merely boiling.
53 Thomas, the sentence that caught my eye was, “How could these cold-blooded creatures have survived on Alaska’s North Slope?”
The paper was in 2005, so it’s aging, and dinosaur metabolism is an active subject. Maybe they were some ways between warm and cold blooded, where they could drop their core temps in winter. Every spring crank up the metabolism and gorge, building blubber, and then chill all winter.
Re my 50 The tidal torque a mass raises on a planet via it’s equatorial bulge is maximum when the mass is overhead at ~ 45 deg latitude …
But a greater torque (proportional to sin(tilt relative to the mass)is required at higher tilts in order to produce precession at the same rate(relative to the mass). I haven’t gone through the math but given the shape of the equatorial bulge relative to a sphere and the smoothness of the tidal acceleration field, I’d guess the torque is proportional to sin(2*relative tilt) (A physics textbook gives the same proportionality for tidal drag with a tidal bulge (idealized, prolate spheroid); an equatorial bulge is like a negative tidal bulge (of that shape) and the angle is the complement of the other angle as they have been defined, so this should be true assuming this wasn’t a typo or mistake in the textbook). If so, the actual (angular) rate of precession would be proportional to sin(2*rel.tilt)/sin(rel.tilt) = 2*cos(rel.tilt)*sin(rel.tilt)/sin(rel.tilt) = 2*cos(rel.tilt), which peaks at 0!
So I think I had it backwards with regards to precession rates varying with tilt relative to orbital planes – however, within that orbit, precession should still peak at maximum torque because the whole orbit is what defines the orbital plane, which defines the center of the axial wobble, whereas at any moment the axis is moving in one direction – it’s over time that it makes the circle, so the tilt relative to the orbit must exceed 45 deg by some amount for the rate of precession to peak for the time-average.
The torque vector at any one time is perpendicular to the plane containing the planet’s axis and the mass, and after a quick sketching excercise, it looks like this vector rotates so that (assuming the precession in one orbital period is negligable), with it’s origin placed on the axis, the tip (terminal point) seems to trace out a loop that passes through the axis and is otherwise entirely on the same side of the axis as when it reaches it’s maximum magnitude if the orbit is circular, so the average effect is in the same direction as it is when the mass is farthest from the equatorial plane; it completes this loop twice per orbit. The loop is not in the plane of the orbit so there will be an obliquity cycle with half the orbital period; an eccentricity could distort the loop (it’s shape and the time spend in any one part of the loop, which will be different for every other loop given 2 loops per orbit) and cause some net change in obliquity that perhaps could build up with time, thus 2 bodies may be sufficient for obliquity changes even without greater complexity (tidal drag, the actual shape of the tides, etc.). I could try graphing the actual shape of this loop for various parameters to see if this all checks out but I’ve spent way too much time on this already (and it’s a little bit OT) – maybe later, much much later.
Second paragraph contradicts itself and prior paragraph – What I meant to write before I got confused is (if no eccentricity, or setting that issue aside) the rate peaks at those times in the orbit when the mass is closest to or crosses 45 deg (in a sense, even more so if this happens when the mass is above the highest latitude (overhead latitude is what I meant by relative tilt or rel.tilt above, at least in the first paragraph) – because (it seems to me that) the rate is in the direction of the orbit-averaged rate at that point; at other times the rate has components perpendicular to that).
Re Titus @52, in a sense everything is a survivor of something previous. But I don’t think a global fog as such would have existed very long; and that sounds different from the topic of your original question regarding a water canopy. Of course the evolution of land plants is far-removed from massive CO2-H2O greenhouse atmospheres of the Hadean, etc.
However, still not quite a water canopy, but I did remember that it’s been suggested that in the aftermath of an impact (such as K/T), local heating of the water at the impact site could produce temperatures so high that a hurricane could develop with exotic characteristis – it would be a hypercane, and it would in some ways be like an F8 or maybe F12 tornado (not sure offhand which number it would be – http://www.spc.noaa.gov/efscale/Fujita1002.jpg). Aside from local damage along it’s path, it would pump H2O into the stratosphere. Maybe not enough to be a water canopy? But enough (if repeated time and again as the heat lingers) to mess with the ozone layer, providing yet another possible extinction mechanism. I saw this on an episode of “Megadisasters” – I think Kerry Emanuel’s work was mentioned, though it’s been a few months.
Re 53 thomas hine – an important point that is perhaps more On Topic – the global climate depends on the greenhouse effect and albedo. Albedo in part depends on snow and ice (and the latitude and season they are found at, and for snow, whether it falls on trees or a bog, etc.), and vegetation, etc. But snow and ice depend on regional climate, which depends on circulation and it’s heat transport. If you increase equator-to-pole heat transport than the global climate has to get colder before the positive snow/ice albedo feedback can kick in. Ways to do that – maybe rearrange the continents and oceans, put up some mountain ranges to deflect air flow … although the behavior of extratropical storm tracks may provide a negative feedback to that. Reduce the coriolis effect, I think, but that doesn’t apply to the Miocene. If continents are very large then they may have dry interiors and large seasonal swings in temperature may prevent an ice sheet from forming even if in the polar position and cold on average. But Alaska was near water… well, if warm enough, proximity to ocean, depending on winds, could simply reduce wintertime freezing conditions, although cooling with a small seasonal temperature cycle is more conducive to ice sheet growth. Remember having relatively warm water nearby (Gulf Stream, North Atlantic Drift) can provide a moisture source and it can snow more if not too cold – (much of?) Antarctica is by at least some definitions a desert. There’s a lot of factors. Generally, though, CO2 is one of the dominant players over geologic time and even orbital time or shorter. PS CO2 doesn’t act as a positive feedback to orbital-time scale changes as a general rule, it’s just that the Earth is at least at present set up for that to happen.
Thanks for responding, I’m glad this is of interest to others as well. Seems to be on the outer limits of knowable science (as acknowledged in the IPCC reports and in the wide array of explanatory (and differing)papers as provided by Patrick), but vey important to contemplate and not just take “as read”.
Re 61 thomas hine – about obliquity variation: if one pictures a tidal bulge being swept along a line of latitude by the planet’s rotation, then the torque exerted by another object above or below the equatorial plane must tend to increase obliquity relative to the orbit of that object. However, actual tidal behavior would be, I’d think, more complex than that. Still, the article which suggested planets would lose obliquity was not considering any particular geography, and it’s hard to imaging how the tidal bulge would shift in any way to point the component of torque normal to the rotation axis ‘away’ from the other object (consider a view over the North pole of the planet, rotating prograde); note any realistic arrangement of the tides, including all the complexity of oceanic ones, must satisfy the condition that the torque on them in total has a component opposite the angular momentum vector of the planet (or the angular velocity vector – they aren’t exactly aligned in real planets but let’s assume they’re close enough that the distinction doesn’t matter here (could it?)) – unless the tides are activating the release of some energy ie a ‘flubber’ planet.
(A tidal bulge travels like an inertio-gravity wave. An equatorial wave traveling eastward – like if the moon were revolving faster than the Earth’s rotation – could be an equatorial Kelvin wave, which is in the same category. In solids there would be an elastic component. A freely propagatin wave travels so that the wave displacement produces a pressure-gradient force which provides the acceleration that provides the velocity that provides the horizontal displacement that fits the wave form (derivatives and integrals). In a forced wave, there is some additional force, which either increases the amplitude or balances the viscous force (sliding motion, plastic deformation, etc. (including losses to eddies, etc.). If the wave matched the equilibrium forced shape, there would be no remaining such imbalance to force the wave, so this can’t happen when the wave is being damped. The mismatch in phase and amplitude allows continued forcing. The mismatch for the solid tide is necessary in order to drive a liquid or atmospheric tide (note, if the ocean and land just shifted up and down together, nobody would have ever noticed the tides until modern instruments could detect it). The ocean’s waves can’t continually propagate around the Earth because of geography; ocean basins can support freely propagating waves (such as Kelvin waves or something like that going around basins in an anticyclonic direction or with the coast to the right in the Northern hemisphere, etc.) in various configurations with various frequencies – tidal driving will resonate more with some of those, and the amplitude can get larger, etc. (but for energy to be dissipated, again, there must be a mismatch in phase so that there is forcing to do work). This is why so much of the tidal energy is dissipated in such a relatively small part of the Earth’s mass, as I understand it. … Also, I’ve read that the crust’s deformability is not uniform, and it would also sink or rise as an isostatic response to ocean tides (there is a fast-acting elastic component to that) and tidal bulges have their own gravity which feeds-back on the process – I don’t know how much. Some tidal energy goes into internal waves and this plays a role in ocean mixing. … But I think there are people who have this worked out to a large extent – they can model the tides.)
Anywhere, there is geological evidence available to constrain the past histories of various orbital parameters, including in particular days per year, which indicates Earth’s rotation rate (and equatorial bulge size) and thus implies something about the moon’s orbit, which helps determine obliquity and precession cycles, although by itself this doesn’t fully determine everything. If records of orbital cycles sandwhiched between dated volcanic ash could be found… (PS some orbital climate variations continue with or without glaciation/deglaciation – low latitude monsoon variations in particular.) Well I don’t know how much has been found yet. There’s something called tidal rhythmites.
Re my “it’s hard to imaging how the tidal bulge would shift in any way to point the component of torque normal to the rotation axis ‘away’ from the other object ”
Well it’s hard for me; I need to emphasize that a lot of this I taught myself just using physics and geometry, and I haven’t gone into it to a large depth; but the article did contradict another, and I’m inclined right now to believe the later.
In answer to Sidd’s question in #15:
1) How long did these warm episodes last ? The graph indicates on the order of 1e4-1e5 yr ?
The climate optima identified at around 16.4 and 15.7 million years ago in our record correspond to pulses of global warmth each <30,000 years in duration that have also been identified in other deep sea marine core archives (oxygen isotopes in foraminifera) (Zachos et al., 2001). However those deep sea climate records also show that the mid-Miocene was generally warm over several million years. Based on the overall difference between the leaf wax evidence for hydrogen isotopes in precipitation and precipitation today, our best estimate of summer temperatures is ~7 °C over Miocene vegetation versus -4 °C over the modern glaciated surface. (By the way, by summer we are thinking of December, January, February in the southern hemisphere when we expect plants to be growing.) Hopefully other lines of evidence from the same ANDRILL sediment core from the other groups working on the core will shed more light on the variability of climate during this warm mid-Miocene time, so look out for those future studies.
2) How rapid was the onset of these periods ? or is the data not fine enough to tell ?
You guessed right, we don’t have fine enough time resolution in a sediment core to tell how quickly changes occurred.
Yes, despite the warming around the edges and the presence of vegetation during the mid-Miocene there was still a substantial ice sheet on Antarctica. The ice sheet was probably about 50% of the current size, likely mostly on East Antarctica.
In response to Bob comment 1 and 10, these leaf wax hydrogen isotope methods can be applied where we have plants growing and leaf waxes preserved. Conditions cool and the ice sheet re-advances after 14 million years ago, and such warm conditions haven’t been seen since. When the ice re-expands we don’t expect to have much hope of finding plant leaf waxes to analyze in the marine sediments around Antarctica (of course we can use these proxies in other more temperate regions of the world). The ANDRILL AND2 core that I worked on here, spans the 20-14 million year period well. The ANDRILL AND1b core, taken I think the season before, spans the more recent Pliocene, and there is a publication from that: McKay et al., 2012 ‘Antarctic and Southern Ocean influences on Late Pliocene global cooling’ in PNAS, http://www.pnas.org/content/early/2012/04/06/1112248109.full.pdf.
Thank you Sarah Feakins for your post. I think guest posts are great and add to RealClimate’s educational role.
From the ANDRILL page about section “obtain high-resolution sediment cores that record major glacial events and transitional periods over the past 40 million years”
Can these cores be replicated by using different methods, and would these show similar results for the same time periods, ie for 40 million years?
Comment by Joseph O'Sullivan — 19 Jul 2012 @ 9:19 PM
Joseph, 40 million years would have been selected as a target because this spans the time before the development of major ice cover on Antarctica, with the transition to a major ice sheet around 34 million years ago, and then the periods of warming that we studied here (20-15 million years ago).
It sounds like the ANDRILL program has other sites that they have identified that could be cored in the future to get information on other time periods, and from different places around the continent. Ideally yes, we would get evidence with multiple ‘proxies’ and from multiple locations to get as complete a picture as possible of changing conditions.
Some cool stuff to see. It’s crazy they use this huge drill on the ice floating over near freezing water, drill through the ice, go down deep below water and start drilling the rock. Dragging the drill on sleds across the ice, scuba diving to attach flotation to the drill… the visceral work that’s gotta be done. Looks hard but fun… for a few years.
Comment by Unsettled Scientist — 20 Jul 2012 @ 1:49 AM
Re my last “but the article did contradict another” – The description of Laskar’s work was specific; it seemed like http://www.astrobio.net/exclusive/4455/loss-of-planetary-tilt-could-doom-alien-life was making a general statement; however, I’ve found some science articles describing the work this science news article may have been refering to, and they seem to be concerned with planets approaching tidally-locked states or other stable resonances. Probably no contradiction… (although I’ve only see abstracts)
Re 61 thomas hine – when I posted those links @ 54, concerning obliquity, I intended to add them (those I hadn’t read through in full, which may be all of them (aside from reading abstracts) to my reading list, since I got rather curious about it myself. But based on what I got so far, there were only two main apparent points of contention, and at least one is probably illusory –
1 – Laskar did calculations for the Earth and the article about that stated that tidal dissipation would and has increased obliquity. After some more thought I am persuaded that this should be the more general case. The science news article about tides decreasing obliquity seems to be about a particular situation (see my last comment @70), and actually, at least in the case of a tidally-locked planet, I have managed to figure out how obliquity could be made to decrease toward 0 – and even if not tidally locked, if rotation is slow enough and obliquity is high enough, obliquity would decrease, and (hint!) finding the reason why also allowed me to finally understand why the ‘analemma’ is a distored figure-8 rather than a slightly slanted ellipse. But I don’t know if this is the only way that tidal dissipation can plausably reduce obliquity.
2 – ‘climate friction’ – the redistribution of mass as ice sheets form at various latitudes, taking into account the isostatic response to that, can interact with the tidal forces to change obliquity over time. To the extent this happened, and if it ever happened by a large amount, I’m not sure; I don’t know if this would signicantly change Laskar’s 500 Myr(centered approximately at now) graph of obliquity by much or not. I think the bigger questions about this probably pertain the Precambrian and earliest Phanerozoic time – this is what Williams et al, http://www3.geosc.psu.edu/~jfk4/PersonalPage/Pdf/Nature_98.pdf , was about, and the idea of such a large obliquity change was meant to support an alternative to the ‘snowball Earth’ hypothesis; it’s rather far removed from Cretacious and Miocene times.
Because it impacts climate in general I would like to continue this at the Unforced variations thread for July (because I already have some additional stuff prepared, including a great way to visualize how precession of an orbit interacts with precession of a rotation axis to cause obliquity changes), but not here, since it isn’t really all that much about ANDRILL and the Miocene.
Chris, that comparison wouldn’t be in the studies — the science papers describe the work being done. But you can look it up, and articles _about_ the papers do mention the rates of change. And have you read Spencer Weart’s book? First link under Science, right sidebar.
From a quick search, I found:
“… conditions during the middle Miocene are thought to be associated with carbon dioxide levels, probably around 400 to 600 parts per million (ppm). In 2012, carbon dioxide levels have climbed to 393 ppm, the highest they’ve been in the past several million years. At the current rate of increase, atmospheric carbon dioxide levels are on track to reach middle Miocene levels by the end of this century.”
A far different place
Plant fossils from ANDRILL sediment cores shed new light on warmer Antarctica”
The “middle Miocene” — middle of a span of millions of years.
There’s a reason we used to talk about ‘geological rates of change’ as being very, very slow. They were.
Just wondering about the interesting coincidence of the timing of long lasting major volcanism then occurring and the influence it might have had on temps, of vast areas covered in lava. We know about the Columbia River Flood Basalts and others around California such as the Mehrten, Pinnacles and Los Angeles volcanics, in Nevada and other parts of the world. Were there similar events in the oceans (which would have heated things up El Nino style). Could there have been such near Antarctica which might account for the high CO2 levels of Tripati?
The following from some personal notes:
Major volcanism around 17-14 Ma followed by long lasting global cooling. Very large, rapid and fluid (effusive) basalt lava flows rich in magnesium and iron (mafic) (dark in color), but not granite or quartz (felsic) occurred in Washington, Oregon and Idaho, “one of the largest flood basalts ever to appear on the Earth’s surface”. The “Columbia River Flood Basalts” represent the largest group of eruptions to occur on Earth since the Paleogene, over 50 million years ago”, “roughly one flow every 75 years.” “During peak activity the average interval between major eruptions was about 13,500 years”. The Yellowstone hotspot at the time located near the present day unincorporated community of San Jacinto in Elko County, Nevada on the Oregon/Nevada border (south east Oregon and north east Nevada). Nearby is also McDermitt.
“Almost everything about this volcanic province is impressive. The Columbia River Flood Basalt Province forms a plateau of 164,000 square kilometers [others say 259,000] between the Cascade Range and the Rocky Mountains. In all, more than 300 individual large (average volume 580 cubic km!) lava flows [“along with countless smaller flows.”] cover parts of the states of Idaho, Washington, and Oregon. At some locations, the lava is more than 3,500 m thick. The total volume of the volcanic province is 175,000 cubic km. Eruptions filled the Pasco Basin in the east and then sent flows westward into the Columbia River Gorge. About 85% of the province is made of the Grande Ronde Basalt with a volume of 149,000 cubic km (enough lava to bury all of the continental United States under 12 m of lava!) that erupted over a period of less than one million years. Flows eventually reached the Pacific Ocean, about 300 to 600 km from their fissure vents. The Pomona flow traveled from west-central Idaho to the Pacific (600 km), making it the longest known lava flow on Earth (the major- and trace-element compositions of the flow do not change over its entire length).’ http://volcano.oregonstate.edu/book/export/html/486
The lava spilling out of cracks and fissures, moved about 5 km per/hr or “1-to-8 m/sec” and up to 40,000 sq km in a matter of days. “It is difficult to conceive of the enormity of these eruptions. Basaltic lava erupts at no less than about 1,100 degrees C. Basalt is a very fluid lava; it is likely that tongues of lava advanced at an average of 5 kilometers/hour — faster than most animals can run.” Clarence Hall concurs saying that the volcanic events at the time were not accompanied by vast ejections of ash into the stratosphere. The lava was 100 ft deep (average?). It eventually covered 300,000 – 500,000 sq km filling valleys. It buried the trees in the present day Ginkgo Petrified Forest in Central Washington. “The lava, as it flowed over the area, first filled the stream valleys, forming dams that in turn caused impoundments or lakes. In these ancient lake beds are found fossil leaf impressions, petrified wood, fossil insects, and bones of vertebrate animals.”. Though there were several flows (lasting from 17.5 and 6 Ma) the Wanapum Basalt (Roza Member specifically) is specific to my period of interest flowing from 15.5 and 14.5. It was smaller than previous flows only accounting for 5% of the total Columbia River Basalt flows. Though less in quantity it covered much of the previous “Grande Ronde” flow area which accounted for 90% of the total. See Mascall Formation below in Description section. According to some the carbon from the CRFB ended up in Monterey deposits (the Monterey Formation)?
As noted before the Wanapum basalt from 15.5 and 14.5 m.y. only accounted for 5% of the total. Again coincidentally the temps begin to drop at around 14.5 mya. Perhaps the heating power of that much raw hot lava on the ground and in the oceans had an effect which declined when the lava did?
Ron R. — Thanks for data about the basalt flow on which I now live.
I thought somebody upstream asked about the heat content brought up from below by these lave floods. On the scale of global climate, negligible. The expressed CO2 could make a difference, though.
Comment by David B. Benson — 24 Jul 2012 @ 9:33 PM
Thanks David. I thought on a global scale it might be. On the other hand there were a lot of regular long surface flows over a long period of time. According to the USGS filling 40,000 cubic miles with lava. I’ve also wondered about a more or less permanent El Nino style heating from hypothesized undersea volcano(s). It was definitely an active time, and the timing is interesting.
By the way, I hope it was clear that most of that was quotations. Just stuff I’ve saved.
Two large asteroid strikes in Germany at Steinheim and a much larger one (six to ten times larger) at Nordlinger-Ries around 15 mya. “The original crater rim had an estimated diameter of 24 kilometers (15 mi). The present floor of the depression is about 100 to 150 m (330 to 490 ft) below the eroded remains of the rim …Recent computer modeling of the impact event indicates that the impactors probably had diameters of about 1.5 kilometers (4,900 ft) (Ries) and 150 meters (490 ft) (Steinheim), had a pre-impact separation of some tens of kilometers, and impacted the target area at an angle around 30 to 50 degrees from the surface in a west-southwest to east-northeast direction. The impact velocity is thought to have been about 20 km/s (45,000 mph). The resulting explosion had the power of 1.8 million Hiroshima bombs, an energy of roughly 2.4×10^21 joules.”. http://en.wikipedia.org/wiki/Nördlinger_Ries
Interestingly, and coincidental to everything else going on at the time there is evidence that the earth’s magnetic field reversed in record time, in just one to four years at 15 Ma, from N to S (needle pointing south).
For what it’s worth, 5*10^5 J/kg * 4 = 2 E6 J/kg, divide by 700 K, that’s a cp ~ 2.9 E3 J/(K*kg), which doesn’t sound too odd (I think rocks’ cp’s are typically smaller at room temp but they might get larger at higher temps)
So if it’s overall (solidifying and cooling) 2.5 MJ/kg, and ~ 2.3 – 3 Mg/m3 …
(multiply by volume, divided by time, divide by global surface area… (~ 510 trillion m2, I think)
The latent heat of melting is the amount of energy needed to convert a solid substance at its melting temper- ature to a liquid at the same temperature. For typical volcanic rocks, the latent heat of melting is around 5×105 J/kg, which means it takes 5×105 J to turn 1 kg of volcanic rock from solid at its melting temperature to liquid at the same temperature.
The latent heat of melting is the amount of energy needed to convert a solid substance at its melting temper- ature to a liquid at the same temperature. For typical volcanic rocks, the latent heat of melting is around 5×105 J/kg, which means it takes 5×105 J to turn 1 kg of volcanic rock from solid at its melting temperature to liquid at the same temperature.
Re Ron R. – here’s what I get using 2.5 MJ/kg, 2800 kg/m3, and the volume of 40000 mi^3
1.167 E24 J –
if over 1000 yr, 37.0 TW; over 100 kyr, 0.37 TW; over 1 Myr, 0.037 TW
over 500,000 km^2, that’s 74, 0.74, or 0.074 W/m^2
over the globe, that’s 0.0725 W/m2 if over 1000 years, etc.
(global average geothermal flux is a bit under 0.1 W/m^2; anthropogenic combustion and tidal dissipation are smaller stil)
(for a 7 km deep layer of rock, over 150 Myr, that’s 0.01 W/m^2 – I don’t know the average age of oceanic crust offhand (and depth is from memory) but that’s the point of this comparison. There’s of course the cooling of the underlying lithosphere after it forms, too.)
ReCAPTCHA has the formula for hydrogen peroxide. Interesting.
Will Gleason, try google. Type ruddiman 2010 A Paleoclimatic Enigma? into the search field and you’ll get a link to uidaho with a PDF. I’d paste a link but am using my buddy’s iPad so doing those kinds of things are annoying on this device.
Comment by Unsettled Scientist — 1 Aug 2012 @ 12:13 PM
My oh my. Time for you guys to comment on what’s happening with Christy, Watts et al. I’m well aware that this post will never see the light of day on this, the most ardent (and biased) of the pro-CAGW blogs but if you maintain the “high moral ground” you’ll lose out bigtime to those that are more sceptical. Christy’s evidence to the Senate, if it ever gets picked up by the MSM, will fry you guys. Similarly if Watts puts in SD values for his data and they show significant differences amongst the groups of stations you’re going to have a lot of explaining to do to convince the hoi polloi that you’re right and the sceptics are wrong.
Christy’s evidence to the Senate, if it ever gets picked up by the MSM, will fry you guys.
Apparently Christy, and you, have missed the fact that the #4 author of the paper, the Grand Poobah of Audit himself, Steve McIntyre, has pointed out that the paper has some very serious flaws and that he doesn’t want his name associated with the paper unless these flaws are addressed and corrected.
RPSr, the godfather of the paper, is also walking back his claim that this is a huge advance, game changing, Watts walks on water, etc.
He states that he’s deeply annoyed with himself for having missed obvious problems, which he blames on the fact that he was only brought in over the weekend to help with statistics.
Speaking of statistics, Watts states that he started teaching himself statistics on Friday afternoon and posted the paper on Sunday afternoon. Overturning a big chunk of climate science in the process.
Ian, the paper is unpublished and unpublishable in peer review in current form. Probably biggest issue is TOB problem. McIntyre is retreating from it, Peikle likewise. Critiques everywhere if you looked. A little skepticism about papers you like might help. You could try looking at skepticalscience.com to see whether your “evidence” will really “fry” any real working scientist.
To say I was surprised to see my comment (#89) had been published would be an understatement so thank you for that. Also thanks to those who took the trouble to comment. With regard to Dr Christy I wasn’t referring to his involvement with the Watts paper. I wasn’t. I was referring to his evidence to the Senate on the association of climate change with extreme weather events. He clearly showed that these extreme events had occurred at least as frequently in previous years notably the 1930s. The data he presented were very persuasive. With respect to Steve McIntyre’s walking away from the paper (#91 and #92), he clearly isn’t asis shown by his comment “Anyway, now that I’m drawn into this, I’ll have carry out the TOBS analysis, which I’ll do in the next few days”. That said I think Mr Watts could have been less melodramatic. If however subsequent statistical analyses, which should have been performed prior to his grand announcement, show significant differences in the data from the various classes of stations this will pose some questions as to the validity of previously reported temperature increases in the US
I am curious why you find Dr. Christy’s testimony persuasive–after all, he has cherrypicked a quite anomalous decade–the 30s. And there are several studies that show significant increase in the proportion of Earth’s land area in severe drought since the 1970s–a phenomenon not addressed by Christy.
What is more, even if Christy were correct, why do you think this would pose a problem for mainstream climate science?
With respect to Steve McIntyre’s walking away from the paper (#91 and #92), he clearly isn’t asis shown by his comment “Anyway, now that I’m drawn into this, I’ll have carry out the TOBS analysis, which I’ll do in the next few days”.
He’s walking away from the conclusions. He has stated that if Watts doesn’t deal with changes in TOBS properly, he will not allow his name to be associated with the paper.
If however subsequent statistical analyses, which should have been performed prior to his grand announcement, show significant differences in the data from the various classes of stations this will pose some questions as to the validity of previously reported temperature increases in the US
He also needs to post his data on the classification of stations.
“To say I was surprised to see my comment (#89) had been published would be an understatement so thank you for that.”
Then perhaps you ought to examine how you came to be so confident about your baseless expectation.
I’ve had comments suppressed on RC. It’s not because I’m a denier (I’m not). Based on the nature of those comments, the comments of the moderators and common sense, my conclusion is that you should think twice about naming names if you want to be critical, even implicitely or indirectly. Some names are protected more than others of course. Note how your comment above only named people whose actions you approve of.
Comment by Anonymous Coward — 2 Aug 2012 @ 8:33 AM
Ray Ladbury (#98) comments that Dr Christy cherry picked the 1930s as being an anomalous decade. Well not really for if the current or previous decade is showing the same pattern it clearly won’t be anomalous. Will it? In any event whether or not the weather events in the 1930s are anomalous, it shows that extreme weather events have occurred in times not currently thought associated with climate change caused by human actions. Obviously if a pattern of events similar to the events in the 1930s occurs now, why would this be anymore influenced by human actions than in the 1930s? Why shouldn’t the events now be due to the same causes as in the 1930s? Obviously thaty possibility couldn’t be ruled out. Could it? I’m sorry but I don’t understand why selecting the 1930s is cherry picking
An issue has been identified in the processing of the data used in Watts et al. 2012 that was placed online for review. The authors are performing detailed reanalysis of the data for the Watts et al. 2012 paper and will submit a revised paper to a journal as soon as possible, and barring any new issues discovered, that will likely happen before the end of September.
> if the current or previous decade is showing the same pattern
> it clearly won’t be anomalous. Will it?
Depends. What has changed since the 1930s?
Assume for now the 1930s was wholly natural variation, ignoring the CO2 increase to that point.
Assume for now the current variation is wholly natural, ignoring the CO2 increase to this point.
Does that make sense to you?
Now, assume the current variation includes the expected effect of increased CO2, on top of natural variation. How much of today’s conditions would you attribute to the change in CO2? How much of today’s conditions would you attribute to natural variation?
Now, what if you take the assumed natural variation from the 1930s,
and add to that the variation expected from the increase in CO2 since then.
What conditions would you expect today, adding both together?
Ian wrote: “Why shouldn’t the events now be due to the same causes as in the 1930s? Obviously that possibility couldn’t be ruled out. Could it?”
What you are saying is that we can’t rule out the possibility that the gigatons of carbon that human activities have added to the Earth’s atmosphere over the last century has NOT had the effect that basic physics tells us it MUST have.
It’s up to you to explain how that could be possible.
Ian says>it shows that extreme weather events have occurred in times not currently thought associated with climate change caused by human actions
Congrats, this is well known by the climate science community. Find me any climate scientist who has said extreme weather events have *not* occured in the past, uninfluenced by human driven climate change. You won’t find one. It is not logical to X event occurred in the past without human influence therefore humans cannot do it.
High speed hadrons collide all the time without humans having done it in the past. We do it with super colliders now. Mountains fell under natural processes in the past, we use dynamite now. Are these events just part of the natural pattern? That something in past occurred due to different causes does not rule out the current scientific consensus of the cause. These aren’t new questions you are posing, they have been dealt with decades ago.
You fell on your face once when just walking and tripping over your own feet. Today I stick my leg in front of yours and you fall on your face. Obviously I had nothing to do with, it was just a natural event because in the past you have fallen on your face without me intervening.
Need more examples of this logical fallacy?
Comment by Unsettled Scientist — 2 Aug 2012 @ 3:31 PM
Ian said:”He clearly showed that these extreme events had occurred at least as frequently in previous years notably the 1930s. The data he presented were very persuasive.”
Actually, Christy did not show any such thing. Many US stations started taking data around 1900, a few following decades were very cold because of extensive volcanic activity. It is no surprise that the 1930’s which had little volcanic activity, poor land use leading to dust storms, and a short number of years to “beat”, had record temperatures.
Oooooh, I just thought of a good example for the logical fallacy that because events (such as warming or extreme weather) have occurred in the past due to natural causes means that humanity cannot cause them. Earthquakes! I like it because it is a phenomenon that covers a huge area. The Earthquake happens in DC/Virginia and people in New York feel the shaking. It was SciFi to think of the military creating an space-based earthquake gun (Under Siege 2). But we do it now with fracking. Pump a ton of water and other junk down into the Earth, boom, earthquake!
Now I can already predict some saying that fracking doesn’t cause earthquakes. That too is an analogy to the climate debate. On mainstream news television you’ll see people claiming it’s not true that fracking causes earthquakes (or that AGW isn’t real). Neither of these are the interesting scientific questions anymore. It’s been studied and a consensus built. The interesting scientific problem now is predicting the magnitude of the earthquakes.
In news media you’ll see debates about whether fracking can cause them, whether AGW exists. This does not reflect the scientific discussion.
Comment by Unsettled Scientist — 2 Aug 2012 @ 4:03 PM
Ian, it is not just the decade that is cherrypicked. Whenever a denialist focuses on the 1930s as the worst ever, they also focus on the continental US. The 1930s were indeed extreme…in the US. And it was extreme for cold as well as warm. But the US is not the world, and when you have records being not just broken, but shattered on a yearly basis, and when high temperature records are outnumbering low records 20:1, then a curious mind…one not blinded by ideology…might wonder what is going on.
101 Ian says: ” In any event whether or not the weather events in the 1930s are anomalous, it shows that extreme weather events have occurred in times not currently thought associated with climate change caused by human actions. Obviously if a pattern of events similar to the events in the 1930s occurs now, why would this be anymore influenced by human actions than in the 1930s?”
Ummm. What gave you the idea that the dust bowl wasn’t influenced by human actions?
107 Unsettled said, “I can already predict some saying that fracking doesn’t cause earthquakes.”
Well, your phrasing is misleading. The total quantity of earthquakes is set by continental drift. So, one can have a HUGE earthquake which kills thousands and destroys much property, OR one can have a hundred small earthquakes which do nobody any harm. I’d say that causing hundreds of earthquakes is a GOOD thing. Wouldn’t you?
Re my 85″There’s of course the cooling of the underlying lithosphere after it forms, too.” – not to give the impression that lithospheric mantle is simply rock formed from magma deeper under the surface – my understanding is that it is the leftover rock from partial melting that produced the magma to form crust; it is to at least a large extent that which didn’t melt in the first place (I think) and is just cooling because it’s been brought closer to the surface in the process of mantle convection. Anyway, back to extreme weather etc…
On second thoughts perhaps I will be given the chance to answer some of the critics. Comment 109 asks “Ummm. What gave you the idea that the dust bowl wasn’t influenced by human actions?” If this poster had read what I wrote this comment would, perhaps, not have been made. What I actually said was “..extreme weather events have occurred in times not currently thought associated with climate change caused by human actions”. Comment 108 implies I have “a mind blinded by ideology”. I could say that any one who cannot see that previously there have been extreme weather events not due to human production of CO2 but still seems to believe that current events can only be due to human CO2 production, also has a mind blinded by ideology. Christy clearly shows that since the 1930s extreme high temperatures have been and still are declining. The increasing ratio of high to low temperatures in the recent decade could well be due to human factors such as land clearing not human CO2 production. Comment 104 is more an article of faith than a reasoned scientifically based assessment. Comment 106 cheerfully ignores the Stromboli eruption of 1930 which, according to the author, should have lead to colder following decades. However several of these decades were still warmer than currently is the case. Why is that? Comment 107 clearly shows the author is responding to something i didn’t say. He states the logical fallacy that previous events cannot have been caused by hunan action. I actually said “not currently thought associated with climate change caused by human actions”. I guess that’s enough but I hope that this post isn’t deleted because it argues a case that isn’t compatible with the preconceptions of those that usually post to and possibly those that moderate, this site.
Ian, please explain the substantive difference between “In any event whether or not the weather events in the 1930s are anomalous, it shows that extreme weather events have occurred in times not currently thought associated with climate change caused by human actions. Obviously if a pattern of events similar to the events in the 1930s occurs now, why would this be anymore influenced by human actions than in the 1930s? Why shouldn’t the events now be due to the same causes as in the 1930s? Obviously thaty possibility couldn’t be ruled out. Could it?” and the implication that humans are not the cause. What are you trying to imply here?
An honest reading is that you are saying since it happened in the past due to natural causes, we cannot rule out human causes. Modern climate science has specifically done just that, ruled out the natural causes of climate variation. Are you just looking to get a basic understanding of climate science in general? Some causes of change are natural, some are human causes. It sounds like you started off with Christy “frying” modern climate science, but now are saying you don’t know the first thing and are looking for what could cause climate to change at all? I have a feeling you’re just playing a semantical game and aren’t really interested in learning how we are causing the climate to change right now.
Comment by Unsettled Scientist — 3 Aug 2012 @ 10:49 AM
OK, Ian, you managed not to dismiss my question to you in 103; the others ask basically the same thing — do you understand that the change in CO2 changes the temperature, and that’s added to natural variation?
If you don’t believe CO2 changes the temperature, then yes, you can believe what’s happening is the same thing both in the 1930s and the 2010s.
Add the change from increased CO2 to the natural variation.
Ian claims:”Comment 106 cheerfully ignores the Stromboli eruption of 1930 which, according to the author, should have lead to colder following decades. However several of these decades were still warmer than currently is the case. Why is that?”
Stomboli has been continuously erupting, and with very low explosive index. There are even categories of VEI which are called Strombolian. Google image search with “20th century volcanic forcing” shows clearly volcanic forcing (which is negative) around 1900 is larger than at mid 19-th century.
Ian cheerfully ignores what else I said, one of which is that number of record is not equal to number of extreme events. To keep it simple imagine how many records are set in the first year of a station? Answer: 365 high records and 365 lows (unless it is a leap year)!
Indeed Hank! Citation very much needed. Jim Larson @110 has mirrored the “it’s good for you” argument of the AGW denialati. Since I preemptively stopped the “fracking doesn’t cause quakes” argument, we skipped right to “it’s good for you.”
Jim, please prove me wrong. I love learning about the natural world, so if there is peer reviewed science out there saying fracking reduces the frequency of “HUGE” earthquakes, I would love to learn about it. If this is true, wouldn’t it be smart to pump water into the California ground to cause a lot of small earthquakes?
Comment by Unsettled Scientist — 3 Aug 2012 @ 11:36 AM
Ian: To say I was surprised to see my comment (#89) had been published would be an understatement so thank you for that.
Ian: I hope that this post isn’t deleted because it argues a case that isn’t compatible with the preconceptions of those that usually post to and possibly those that moderate, this site.
Ian apparently has been given a load of bull about RC.
Anonymous Coward: I’ve had comments suppressed on RC. It’s not because I’m a denier (I’m not).
Same here. Numerous times. Does it bother me? Not in the least. I don’t know how many posts don’t make it through. I suspect most everyone has had posts not published.
One has to keep in mind that this is a blog with a moderator and he/she is within his/her rights not to publish comments that are not contributing to the discussion at hand, otherwise it would be chaos.
That said, my feeling is that RC usually bends over backwards to try not to censor, thus we see OT comments and poorly thought out arguments fairly often. One senses though that the moderator(s) are allowing them with a certain gritting of the teeth. Perhaps censorship prevents people from making a public fool of themselves.
Helpful hint: Relax, unclench that anus and don’t take yourself, your wisdom or your supposed importance to the world tooo seriously and you will be fine.
So which “Jim Larsen” are you? Several people by that name have rather responsible positions related to climate or public policy and blog quite a bit, but there’s no way for us to tell who’s who from the name alone. Your background would help understand where you might be getting the estimates you’re quoting, if you care to tell us what source you’re relying on and if it’s someone else’s policy paper.
” If this is true, wouldn’t it be smart to pump water into the California ground to cause a lot of small earthquakes?”
Yes, I’ve read exactly that, though it was long enough ago. Basically, every small earthquake could be said to have prevented/reduced a larger earthquake at a later date. I’ll wander the web and see what is available, but essentially I’m starting at zero. I’ll let you know what I find, if anything.
112 Ian prebvaricated “On second thoughts perhaps I will be given the chance to answer some of the critics. Comment 109 asks “Ummm. What gave you the idea that the dust bowl wasn’t influenced by human actions?” If this poster had read what I wrote this comment would, perhaps, not have been made”
I read and quoted precisely what you wrote. “In any event whether or not the weather events in the 1930s are anomalous, it shows that extreme weather events have occurred in times not currently thought associated with climate change caused by human actions. Obviously if a pattern of events similar to the events in the 1930s occurs now, why would this be anymore influenced by human actions than in the 1930s?””
Are you claiming or not claiming that the dust bowl was not influenced by human actions. My reading is that you are making the implicit claim that the dust bowl was not influenced by human actions. If you are not claiming that the dust bowl was not influenced by human actions then I have no idea what you are talking about.
“Basically, every small earthquake could be said to have prevented/reduced a larger earthquake at a later date”
Pure baloney, and you’ll not find any support for that idea at any earth science site. Take the time to read the link Steve Fish gave at 121.
>Jim Larsen says: I’ve read exactly that. But I’m essentially starting at zero.
I guess you missed both requests for a citation. Here’s a third request for some peer reviewed science saying exactly that. Not sure what you mean by starting at zero, does that mean you didn’t read exactly that ? Either way we await any actual evidence from the literature.
Comment by Unsettled Scientist — 3 Aug 2012 @ 7:04 PM
Re Ian – “I could say that any one who cannot see that previously there have been extreme weather events not due to human production of CO2 but still seems to believe that current events can only be due to human CO2 production, also has a mind blinded by ideology.”
Few if any people believe that the only reason the Earth continues to rotate and the moon still raises tides and water still boils at ~100 deg C at sea level, is that humans are propping it all up with CO2 emissions. More to the point, of course some extreme events would be happening now without anthropogenic CO2 or anthropogenic anything for that matter. But humans have pumped CO2 into the atmosphere (and other things) and this has effects. You can see the ‘bite’ CO2 takes out of OLR in spectra from satellites, and this is as can be predicted, and given the shape of that bite, and the shape of the absorption spectrum which produces it, a doubling of CO2 will under present Earthly conditions (be careful about applying this to Venus, etc.) block some 3.7 +/- 0.5 W/m2 of OLR, global average (going from memory here)(this is something that can be calculated – although great accuracy requires a lot of number crunching, the underlying physics and math is simple – thermodynamics via Kirchoff’s law (of thermal radiation), conservation of energy via Schwarzchild’s equation) (after stratospheric adjustment) – meaning that if nothing else changes, Earth’s climate system (below the tropopause) heats up at that rate. Well if you gain heat, either the temperature goes up or you melt something, or both, etc. Temperature increase increases OLR and that’s how equilibrium is restored, although the amount of change required can be amplified or reduced by other feedbacks; models with known physics, paleoclimatic evidence, and historical observations all suggest a net positive feedback (after the Planck response) and they converge toward the same range.
With temperature increasing, the saturation vapor pressure of H2O increases – not that the atmosphere tends toward 100 % RH everywhere – some parts are actually very dry, but that’s understandable given the way air circulates and given precipitation – but generally the atmosphere will gain H2O and water vapor provides concentrated heating mid-air in updrafts; the water vapor abundance changes the convective energy flux differently than it changes the energy available in the air and so this affects the circulation. surface albedo feedback and effects on when and where sea ice occurs affect horizontal temperature variation, and this affects the circulation. Circulation affects where precipitation occurs. There’s more than just temperature change that happens; but if you raise the temperature and hold variability constant (not that variability can’t change), you get fewer extreme cold spells and more frequent and more intense heat waves.
Starting with the basics, you could expect short-term variability in the midlatitudes to be reduced with GHG, H2O feedback, and aerosol cooling effects on DTR, and also a reduced overall temperature variation pole-to-equator, reducing the temperature variation associated with air masses and fronts, etc. – however that last part isn’t quite so simple (seasonal, not even over latitude, not the same Northern vs Southern hemisphere – see wind-driven upwelling, etc., there’s probably other stuff) – but changes in precipitation location and timing can cause drying in places – is expected to – and if that regionally reduces H2O vapor and cloud cover, you can get larger DTR and without evaporative cooling, extreme heat waves can amplify. Also warmer winters can lead to more snowfall, up to a cutoff point. Greater available latent heat may fuel more intense extratropical and tropical cyclones. From some physics of atmospheric circulation, a given SST anomaly should tend to cause greater impact in atmospheric circulation (ENSO-style) when it is on top of a higher average temperature. This isn’t quite as simple as the basic ‘more GH effect = higher temp’ and there’s a lot I’m not sure about offhand, but there are people who study it.
“Christy clearly shows that since the 1930s extreme high temperatures have been and still are declining.” – Does he? Globally? Christy isn’t exactly a go-to source for me – please explain how he does this.
“The increasing ratio of high to low temperatures in the recent decade could well be due to human factors such as land clearing not human CO2 production.” – fine if you have no data to go on; why ignore the body of knowledge already gained. Was there a recent boom in land clearing in the U.S.? What effect would that have?
Not on the point of extremes but more generally, it should be pointed out that there are differences in the spatial-temporal effects expected of different forcings, and this is used in attribution studies.
“Comment 104 is more an article of faith than a reasoned scientifically based assessment.” – See Hank Roberts @ 118 and my first paragraph – it deserves emphasis.
“He states the logical fallacy that previous events cannot have been caused by hunan action.” – Do you mean (according to someone else) that human action couldn’t have been a factor 80 years ago? Or 200 years ago? 5000 years ago? No, of course it was a factor in some things, though of different kinds and sizes (for climate, global average anthropogenic forcing has increased a lot since 1930). Much of the last 800,000 years, not as much. Hundreds of millions of years ago? Well I don’t think Emmitt Brown ever took the Delorean there.
The logical fallacy being addressed was that just because something that happened was not caused by humans in the past doesn’t mean humans can’t cause it now (in fact it helps us understand what effects we may have – CO2 changed naturally in the past – although usually much more slowly). A related point is that even if natural variability is still occuring, it doesn’t mean there isn’t a human effect (see above)(and there are attribution studies – people don’t just assume this stuff – although if we had no such work to go on, it would still be the safer bet (and we have to make the bet, we’re in this world and living requires decisions) that anthropenic forcings are having effects similar to what is expected based on known physics) – perhaps this may be more directly related to your statements.
“the preconceptions of those that usually post to and possibly those that moderate, this site.” – assumes opinions were arrived at without much care – your preconception, apparently.
Re Ian specifically on the Dust Bowl – well, yes there were human effects aside from global average climate forcing. I don’t know all the details of that. However I thought natural variability did play a role too (in that it was hotter than otherwise – and globally there was a bit of a peak relative to the forced trajectory sometime around then, although … ?) – but anyway, it was quite hot in the U.S. in particular. So with it being hot now, this time in association with greater global average temperatures, there may be differences in what to expect but also perhaps similarities to what happened then. However similar it may be, a big difference is that it won’t simply end it 10 years and not come back for another 70. I think it may be here to ~stay, except for a few anomalously cool years sometime in the near term (because variability isn’t gone), and barring a refreshing supereruption.
for John and Ian both — the dust part of the dust bowl was certainly worse due to the transformation of the buffalo prairie first by market hunting, then by pure stupidity, burning and grazing.
After that came the “sodbusters” — who were misled, to their misfortune, into destroying the roots after the earlier colonists had destroyed the above-ground part of that ecosystem.
Google the phrase “rain follows the plow” for that.
The temperature swing at the time was what it was — Ruddiman’s work suggests anthropogenic warming started well before the 1930s, but it was a small addition to the natural variation at the time; now, it’s bigger.
Hank, I’m nobody in particular and have zip zero nada qualifications. Everything I say here is mere opinion, and often is just thoughts meant to provoke a discussion.
I looked around a bit about earthquakes, and the concept of inducing earthquakes via water injection or even just dropping a heavy weight appears valid, BUT….
first, the magnitudes of devastating quakes are so large that it would take a thousand or a million small quakes to “compensate” for one immense one.
Next, damage caused by the immense one is an “act of God”, which means it’s blameless, while the damage caused by the induced quakes is actionable. Thus, it is “better” to have thousands of folks killed and a city destroyed than to have 1 person slightly injured in an induced quake. This pretty much precludes significant research on the subject.
126 Unsettled says, “I guess you missed both requests for a citation. Here’s a third request for some peer reviewed science saying exactly that. Not sure what you mean by starting at zero, does that mean you didn’t read exactly that ? Either way we await any actual evidence from the literature.”
You didn’t read my post very well. I said I read about earthquake mitigation techniques long ago (and merely reading something doesn’t make that something right) and I’d look at what the current ideas are. I did exactly that, and feel I added to the discussion.
I’m awaiting your citation showing that small earthquakes don’t reduce the stress on faults. Since common sense says that such ought to be the case, I’d say you need to provide citations. If you think my point is wrong, then provide something which substantiates your stance. Otherwise, you’re just wasting bandwidth.
NEVER NEVER NEVER ask for citations without providing YOUR OWN. (yes, this is one of my pet peeves. I refuse to provide citations to someone who doesn’t provide them herself.)
Hank, Re 129
The buffalo prairie also contained a large number of very shallow, perched aquifers resulting from old buffalo wallows. A settler would see a wetland and think there was water. A ten foot deep, hand dug well would yield a bit of water in the wet years, but a drilled well would puncture the bottom of the aquifer, and drain it.
re my – “Starting with the basics, you could expect short-term variability in the midlatitudes to be reduced with GHG, H2O feedback, and aerosol cooling effects on DTR, and also a reduced overall temperature variation pole-to-equator“… It was that last part which pertains particularly to the extratropics, or at least it could in this very basic approach – but note the complexities/caveats…
@Jim Larsen, I *did* provide a citation for my claims! I said that fracking causes earthquakes and the interesting scientific question now is not whether that is true, but how to predict their magnitude. See the link to the paper in Nature? Sorry about your pet peeve, but you’re wrong about me not providing a citation for my claim.
You are the one claiming that fracking has an effect on the total number of HUGE earthquakes. I made no statement about that at all, so what am I supposed to cite? Where is your citation, for the FOURTH TIME? As I said, I love learning about the natural world so if there is any evidence I would love read it.
Don’t make us ask 5 times. Either drop it and realize you don’t have the science to back up what you said, or provide a citation. I don’t need to provide a citation to disprove your claim, I provided a citation to prove my claim (fracking causes earthquakes and the cutting edge of science is trying to predict their magnitudes), provide one to prove yours.
Comment by Unsettled Scientist — 4 Aug 2012 @ 9:05 AM
> The total quantity of earthquakes is set by continental drift.
> mere opinion, and often is just thoughts meant to provoke …
Decline to be provoked. There are lots of blogs where that’s valued. Not so much here where people are trying to learn about the science.
BTW, Jim, common sense is terrible when it comes to science. I think it was Feynman who famously said something to the effect that the purpose of science is to stop you from fooling yourself and you’re the easiest person to fool.
Did you look at the link provided by Steve Fish @121? I did.
“It would take 32 magnitude 5’s, 1000 magnitude 4’s, and 32,000 magnitude 3’s to equal the energy of one magnitude 6 event. So, even though we always record many more small events than large ones, there are far too few to eliminate the need for the occasional large earthquake. As for “lubricating” faults with water or some other substance, if anything, this would have the opposite effect. Injecting high- pressure fluids deep into the ground is known to be able to trigger earthquakes—to cause them to occur sooner than would have been the case without the injection. This would be a dangerous pursuit in any populated area, as one might trigger a damaging earthquake.”
Don’t forget, the Richter scale is logarithmic. All those fracking earthquakes have little to no impact on releasing the energy that is involved in HUGE earthquakes. So there you go, there is one source for you stating the opposite of your claim.
Comment by Unsettled Scientist — 4 Aug 2012 @ 10:00 AM
Thanks to Hank Roberts and Aaron Lewis for providing some facts about human manipulation and the dust bowl, which need to be front and center in teh stupid about dust bowl comparisons. Another massive human engineering fail.
I do wish the fascinating on-topic discussions (Patrick and Ron) that challenge and inform would continue, instead of this guff about Watts appalling but megaphonic anti-science and his public access to the Congressional moneybag hoarders who ignore reality and truth – science’s focus, unlike theirs, is on finding out and learning more.
How much human changes attributed to the dust bowl can not be firmly established. The lack of rain and record temperatures were definitely natural. We just aided natural in achieving the worst agricultural crisis in American history.
[Response: your first two sentences are contradictory. – gavin]
Re 137 Susan Anderson – I’ve been educating myself about obliquity and precession, with the intent to post it (though in unforced variations); but then I decided to start with something related: Chandler wobble – it’s not really climate-related, although that in itself may be a good point because someone out there thinks otherwise – but it is related to ‘true polar wander’ which is another hypothesis related to Snowball Earth… it is also related to the fact (so far as I understand) that precession approximately carries the Earth’s body with it – that is (under certain conditions which the Earth seems to meet present time I guess), you could stick an axle through the symmetry axis of the Earth (the principle axis of maximum principle moment of inertia) and it would approximately follow along with the angular momentum and instantaneous angular velocity vectors – setting aside continental drift, etc (this is something I took for granted until … I think it was a few years ago, somebody brought up the point and it occured to me that I didn’t really know).
Maybe I should post it here after all? (PS might take a few more days)
Relative to Gavin’s comment, I am embarrassed to have to tell you this, but if you ask “How much human changes attributed to the dust bowl can not be firmly established” then you also can’t assert that the lack of rain and temperature changes are completely natural. Why don’t you check this out so you can talk intelligently? While you are at it, do you know whether or not this period in the Midwestern US was just local weather or indicative of global climate? Otherwise, why do you think that this is an important data point on a climate forum. Steve
I do not know its impact, but farming practices of the times left the South Dakota landscape covered in blackdust. Droughts now do not look like this. This picture was taken a few miles from my father’s 1960s ranch near Gann Valley, where a record high was set that still stands.
Dan H, the contradiction is that first you say that how much human contribution can attributed is not possible, then you make a statement of certainty about the human contribution not being there. Thise are mutually exclusive. Honestly, not sure why Gavin didn’t just dump that one to the bore hole or demand you actually provide references because you always get it wrong. Rather than reply to this with more word play, how about you link to whatever it is you’re trying to say, it will be much clearer that way.
Comment by Unsettled Scientist — 4 Aug 2012 @ 10:59 PM
DanH may be incorrect about the Dust Bowl rainfall and temperatures being entirely natural since land use affects both, as does CO2 concentrations, but his two statements are completely consistent. Attributing one pair of factors to natural variability in no way determines the attribution of other factors. Dan’s just trying to limit the scope of possible attribution. The basis for his statements might be the common misperception that since actual NET temperature increases didn’t break through natural variability until recently, CO2 had NO affect until recently.
Is that correct, Dan? Do you believe that increased CO2 concentrations in the 30s had no affect on temperature and rainfall since natural variability somehow precluded it? Assuming “No”, perhaps if you modify your stance to “largely natural” from “definitely natural” and provided a smidgen of logic or evidence, then you would gain more traction.
>Attributing one pair of factors to natural variability in no way determines the attribution of other factors. Dan’s just trying to limit the scope of possible attribution.
He’s limiting it without any evidence or sound reasoning. If you can’t establish how much human activity contributes, then you cannot rule out human activity and say it was definitely natural. CO2 emissions are not the only thing humans to do change climate, so reading CO2 into “human” is also incorrect. CO2 and temperature are not the sole drivers of climate change, especially regional (not global) climate change.
He’s doing this just to argue, just to spread confusion, without anything to back up his assertions. Sound familiar? It’s like saying fracking reduces the frequency of huge earthquakes without any scientific references.
Comment by Unsettled Scientist — 5 Aug 2012 @ 4:04 PM
guys, please, the facts about the dustbowl era are pretty clear. If you must, just stick to them and let Dan H. stew since he doesn’t realize massive fails have consequences. The rest of us seem to realize there are similarities in our conviction we can engineer earth to feed our exploitative needs forever.
That was also a time of great oil well boomishness. How things cycle around, innit?
Patrick027, your stuff is above my head, but that’s the way I like it. Learning is fun and not a waste of time, not now, not ever. When I chose art for my career, one of the reasons is that it will never be fully and completely resolved.
“…but his two statements are completely consistent.”
Logically, yes, but in context, no. That is, in the real world precip, temperature, evapo-transpiration and albedo (to name a few) are not so easily disentangled as that. If human activity can’t have its consequences ‘attributed’ (if that’s not too gross a misuse of the term), then one can’t rule out potential consequences for rainfall and temperature.
But Susan’s right, though I couldn’t resist chiming in, anyway–obsessing about this particular nit is probably not the best idea ever proposed.
You refer to, ” — our conviction we can engineeer earth to feed our exploitive needs forever.” I am not sure what you mean, but it sounds like you would like to return to days of yore, sometime or other. As an artist, that must work for you.
As an engineer, I would work to arrange our resources to avoid floods and droughts as much as possible, whether or not these were caused by CO2, however it got into the air. Also as an engineer, the whole problem must be understood, so arranging our resources must be done to also face the CO2 crisis. Also a part of the problem is the fact that there is a lot of starvation in the world, and it seems we have no problem making it worse by doing such idiotic things as using feed grain for fueling energy guzzling vehicles; done as I recall by environmentalists and politicians in the name of reducing CO2, along with the farm lobby of course.
I see it as unconscionable that we have not done simple things that we knnow how to do, to irrigate and drain land, thereby reducing misery in the world. True, population seems to ever insist on expanding to keep a certain level of misery in being. I don’t have an answer for that.
One relatively simple area of improvement seems possible based on a farm vehicle recently demonstrated by Miastrada Company. Perhaps realclimate folks will see how solving farm labor problems connects with water and land problems which connect with climate problems. Look at http://www.youtube.com/watch?v=xq5eIVVvdgA to see a way we might engineer our resources.
Jim Bullis, change the subject much? I was referring to some striking similarities between the dust bowl era and the present, having to do with heedless overexploitation and failure to regard consequences as having any significance.
I have no issue with engineers if they can make smart changes that improve our lot, which is deteriorating rapidly, but I do take issue with the idea that infinite expansion leads to a positive endgame. A the moment, we appear not to be doing the simple things we could be doing due to political stalemate, and the circular firing squad does not help.
I was struck today by a new AP item about fish deaths in the heat. Consequences are multiplying. Claiming that we are all powerful does not meet the case in real reality.
However, I disregard my own advice, which would indicate I should maintain a stately inattention to these distractive items.
I guess you do not see how all these things are connected, yes, through their consequences.
The “simple things” we might do I am imagining to be the kind of things that impact energy supplies and give industry pause in planning investments. If so, the consequences could be serious to the developed world.
I don’t see anything I said to be ‘claiming to be all powerful’ so you might ask yourself about changing the subject.
Perhaps a dumb question: the time period under question in this topic, the middle Miocene, is famous for its flood basalts which lack the large atmospheric ejections of the more normal stratovolcanos. Does that mean that, though these eruptions released both CO2 and sulfur dioxide, the latter did not make it into the stratosphere where it could have offset the CO2 and cooled temps? Could that help explain the anomalous warming of the period? All positive and no negative?
Thanks for at least trying to understand the consistency – yours appears to be the most coherent response. My statement does not say that the Dust Bowl was entirely natural – that is just a misconception posted by those who contend that it must be one or the other, and cannot be both. My statement is that natural variability is definitely a cause (I never said the only cause) of the American Dust Bowl. I also said that the effects of CO2 on the Dust Bowl could not be ascertained (not that it had no affect). This is mostly due to the calculated effects of the addition CO2 in the atmosphere (only ~6% above the pre-industrial average), is very small compared to the natural variation at the time. Evidence has been presented that other human influences had a greater influence in making the Dust Bowl worse than would have occurred naturally.
This is not a case of either/or, as both natural and manmade cause can affect the environment today and yesterday alike. Not only is there ample evidence for this, but it is the more logical response. Reading through many of the previous posts, I see many people repeat illogical statements that it cannot be one cause or the other, as if only one cause can occur at a time.
148 Unsettled, read my 130 on quakes. I noted the ~3-6 orders of magnitude involved means the results would be so small as to be moot, even if true. I disavowed finding much scientific knowledge. I think that “conclusion” post was reasonable, yet you subsequently and still seem to be asking for more. I don’t see how I can comply.
On Dan’s Dust Bowl, it seems you’re mostly agreeing with me in a way that appears to disagree. Perhaps my saying “land use” once but “CO2″ thrice was confusing since land use was “THE” cause. (No dust bowl this year!) Also, IMO Dan’s not being argumentative. He’s his usual helpful, forthright, and unteachable self. Perhaps if you’d visualize Dunning-Kruger as a handicap? (Interesting that I’m defending Dan by saying he’s “consistently wrong”, and receiving flak for it!)
Also, 1930s US temperatures were influenced by the Dust Bowl itself, so comparing current US temperatures to the 30s (as skeptics do) is tenuous, perhaps needing a sort of Regional Heat Island adjustment. Any experts have an estimate of the effect? It would be a good counter to a common talking point.
On topic, this bothers me: “An aquaplanet is perhaps good enough for these tests as conditions at the coast are really set by the oceans.” I figured that Antarctica’s coastal conditions are often set by katabatic winds. Is that wrong, or was the 50% reduction in ice enough to change the game?
For Jim, you’re asking if, during the Miocene, katabatic wind from the much smaller icecap would still reach –and set the weather at — the coast, dominating the effect of the ocean on the coast?
I’ve been trying to come up with any case where katabatic wind falling off the edge of an ice field extends that far across vegetated land; I haven’t found anything by looking for contemporary examples. Can you?
(Wondering if you have an actual example in mind of the conditions you’re describing as possible, or if you’re ‘asking to provoke’ without a basis for it)
Seems the alternative to the model they used is no model (as they say alternative models don’t have enough information to be used).
Re 157 Dan H. – um,… well that (generally) makes more sense, but I don’t get where you got what others were saying (perhaps I just assumed they weren’t meaning to say what isn’t correct? … or maybe it wasn’t me …)
It can be consistent to say that the CO2 effects cannot be ascertained while still putting a limit on what it may have been (not 100 % of the cause) – and it is generally consistent to say that you can ascertain the extent to which something cannot be ascertained; however, it sounds weird to go on to ascertain (via “the calculated effects of the addition CO2“) just why it cannot be ascertained in such a way that seems to imply that it can be ascertained to some extent.
Jim, when I replied that 130 wasn’t visible to me, only the 131 was there I believe. Regardless, I was mostly replying to your claim that I didn’t provide a citation. Since we now agree there is no science to back up the idea that fracking reduces the frequency of HUGE earthquakes and pumping water into the ground in California to cause smalls ones is a bad idea, we can move past that and let it go.
As for Dan H, the only way I’ve ever found him helpful is in the replies he generates from Gavin, Tamino, Hank and others. I certainly do learn more about the science because of their responses, and I learn how to better deal with people who spread confusion because people like Gavin are ridiculously good at it. By now I’d have pulled all my hair, even my eyebrows, out of my head if I was in his position.
It’s a repeating cycle, Dan H claims the NC legislation is based on more science than the assessment report, it gets pointed out that he’s wrong. He disappears for a couple months, comes back and we’re discussing him again instead of science. I’m partly to fault for getting baited into it. So like the earthquakes, I’m letting this go now as well. Parsing Dan H’s language is not going to lead us towards any kind of enlightenment.
Comment by Unsettled Scientist — 6 Aug 2012 @ 3:34 PM
Jim Bullis wrote: “… we have no problem making it worse by doing such idiotic things as using feed grain for fueling energy guzzling vehicles …”
I’m not sure that’s any more “idiotic” than feeding most of the corn and soybeans grown in the USA to factory-farmed animals raised for meat, with a resulting LOSS of up to 90 percent of the protein available for human consumption — not to mention the resulting epidemics of entirely preventable degenerative diseases.
I was thinking that perhaps the low altitude that SO2 from flood provinces are ejected to prevented it from making a difference, but the CO2 from the same volcanos apparently made it high enough to heat the earth. So maybe it’s as you say, simply the longevity of CO2 over SO2.
It was just an honest question. I didn’t assume that a 50% reduction in global ice makes a significant difference in ice area for the EAIS, nor that there were vast areas of vegetation, so there are no conditions in mind, which is pretty much the basis for the question! I don’t see where the OP is inconsistent with an East Antarctica with essentially no change except a lower ice sheet, no ice shelves, and a TINY fringe of life along PART of the coast. Since Andrill is next to the dry valleys, it could be a special case.
Anybody have a map of Antarctica during the Miocene?
Ok, there is a reasonable argument for vegetarian diets as opposed to meat, fish, poultry intensive diets, though the people European and American continents have been eating meat etc. for thousands of years. And I only assert idiocy when it comes to tinkering with this way of life, which I tend to like.
As to the factory farmed meat, that is disturbing and I am open to being convinced that this is problematic. Certainly we need to be very careful about factory like operations. But if it means that some will come up short of food to eat, our efforts to make the situation better need to be very well supported by evidence.
What we might do to improve productivity in growing of organic crops is something we are looking into in regard to the farm vehicle that we at Miastrada Co. are now testing. By making it more attractive to tend crops with hand work instead of machines we are thinking we can improve things here. Look at, http://www.youtube.com/watch?v=xq5eIVVvdgA to see the concept.
“Certainly we need to be very careful about factory like operations. But if it means that some will come up short of food to eat, our efforts to make the situation better need to be very well supported by evidence.”
The evidence has been in for some time, many come up short of food now because of industrial farming methods, particularly animal agriculture – read the details here . . . look at the graphs here. Your assertions are unfounded and irrelevent, please don’t return to pitches for your products here, even in Unforced Variations.
From the report, “Nor are science and technology by themselves a panacea for world hunger. Poverty, not lack of food production, is the root cause. The world currently has more than enough food, but some 1 billion people still go hungry because they cannot afford to pay for it.”
> ice volume
Ah, when I looked up the Miocene I found the _Antarctic_ ice described as around 50 percent what it is today. The main post refers to “glacial ice” from deep sea records. I didn’t read that as meaning “global” — but perhaps it’s ambiguous.
Iceland is mentioned as a contemporary example in one of the press reports, for what Antarctica may have been like in the Miocene. Here’s one paper on how the catabatic wind behaves on one particular icecap in Iceland, for whatever it’s worth (PDF)
Perhaps a more direct answer comes from the ANDRILL papers; the pollen and plant-derived waxes described from the drill cores fit a coastal ground cover, seems to me. But I’m just some guy on a blog. Plants haven’t changed that much since the Miocene, anyhow.
“… today’s brand of resource-intensive, environmentally destructive agriculture is a poor option. Therein lies the real challenge in the coming decades: how to expand agricultural output massively without increasing by much the amount of land used.
What is needed is a second green revolution …. Such a revolution will require a wholesale realignment of priorities in agricultural research.”
Always, always, check the cite and context; suspect spin. But you knew that.
Yes Hank, always the spin from that quarter, and the limited understanding – as Wanda said “Of course apes read philosophy Otto, they just don’t understand it.”
About the ‘Green Revolution': “… the global increase in crop yields per ha from 1961 – 1999 was accompanied by a 97% increase in irrigated acreage, 638% increase in use of nitrogen fertilizer, 203% increase in use of phosphorus fertilizer, and 854% increased production of pesticides …” http://people.oregonstate.edu/~muirp/agtrends.htm
It’s hardly any wonder when so much of that is invested in animal agriculture that poor folks go hungry.
Much of the world’s population are still subsistence farmers…or in many caseds sub-subsistance farmers.
The town I lived in when I was in Africa had a thriving market where you could pick up fruit, meat, vegetables, staples (rice, flour, corn) and even bread. Things got lean in the hot season, but you could usually find at least bananas.
Fifteen km up a dirt road, the situation was entirely different. The kids there considered carrots a rare delicacy, and during the hot season, dogs started to disappear.
Hunger is not a simple problem. It doesn’t reduce to one or even a few causes. And an agricultural system that produces monocultures of corn and soy is not a solution to it.
Yet, during this period of globally affordable food, still a billion people go hungry. Some people just do not get it. To truly solve the hunger problem, we must first attack poverty. Maybe apes can understand that.
Dan it is not just “poverty”. Poverty and hunger are two sides of the same coin. Yes, poverty matters, but transport matters, distribution of wealth matters, sustainability matters, population matters, culture matters, education matters, land tenure matters, corruption matters. It ALL matters. We solve nothing if all we do is provide calories devoid of nutrition or grown in land rendered toxic or if we increase yield of terrestrial crops while rendering our estuaries fetid cesspools. As an ape, I do understand this. How ’bout you?
Yes Dan, the “real price” of food fell in the developed world during the period that cheap fossil fuels allowed industrial agriculture to develop it’s meat market, your without-context graph does not represent “global affordability” nor extent and quantity of distribution. Please stop your disinformational games.
Although this should be in Unforced Variations I can’t resist. There were 3.1 gig people in the world in 1961, while in 1968, at 3.5 gig people, Paul and Ann Ehrlich explained what was happening and we now, having ignored their caution, have 7 gig people plus global warming, peak oil, fresh water shortages, ocean degradation, habitat degradation (including for food crops), desertification, all of the additional things listed in the recent past by Hank Roberts and Ray Ladbury, and you are concerned about dietary habits? All we need is resource allocation to solve the problem? What do you think would happen if we can produce much more food, even without producing more CO2? We may be Homo but our response so far is not very sapient.
Jim Larsen @ 12:40 PM. I wasn’t sure whether global or local volume or area was “50%”, but 74′s map sure looks like local area is even less than 50% in that rendition.
Not sure what the question is. Is there doubt about the middle Miocene Antarctic ice cap was less than today? The fact that sea levels were so much higher then would show that. 75 – 120 ft higher is the figure I remember. California had a large inland sea, formerly called the San Joachin, now the Temblor. ‘Course The coast was lower then too, but the sea levels were high all over. Look at Florida for example. Evidence of much higher temps.
The map I provided is rough. Like I said, I can’t account for the absolute accuracy.
Anyway, Sarah Feakins in comment 65 above says: Yes, despite the warming around the edges and the presence of vegetation during the mid-Miocene there was still a substantial ice sheet on Antarctica. The ice sheet was probably about 50% of the current size, likely mostly on East Antarctica.
Steve Fish — @ 5:21 PM All we need is resource allocation to solve the problem? What do you think would happen if we can produce much more food, even without producing more CO2? We may be Homo but our response so far is not very sapient.
You nailed it.
IMO, environmentalists have been gagged by the rightwing think tank spin machine from saying what we really mean, from arguing the real issue, so we end up arguing around the edges, arguing the spinners argument. I mean, we surely don’t want to appear anti-human right? And that is how the spinners spin any discussion about population control. So instead we defensively talk small fixes, hoping that people will see the forest for the trees.
The truth of the matter is though that it is the spinmeisters that are anti-human, for what kind of world would their policies leave future generations? None worth living in. It is the policies of environmentalists which, if followed, will lead to there even being a future for the human race.
Steve, see 169 and following, it’s JimBullis and DanH who believe “modern” animal agriculture is no problem and simple ‘resource re-allocation’ will take care of the impoverished starving millions, not I – you could find comments from me here over the long term that specifically show I believe overpopulation is the root of nearly every problem we now face, including climate change, I’m of an age to be quite familiar with the Erlichs. Yes, sorry about the OT posts, but I did apparently dissuade JimBullis – I should know there’s no dissuading DanH.
Ron R. @165 — Thanks for the link; I have yet to visit some of those locations.
Carbon dioxide is a well-mixed gas in the atmosphere with a mixing time of close to 2 years. It is the CO2 at all altitudes that produces the so-called greenhouse feect, not just the CO2 at any one particular altitude.
Comment by David B. Benson — 9 Aug 2012 @ 10:01 PM
David B. Benson — @ 11:15 PM, Yes, someone can correct me if wrong but I read somewhere that peak warming was between 16.25 and 16.75 ma. So if you’re planning on a visit bring your AC.
Another interesting side note from the CRFB volcanism was the creation of beautiful opals. Again from my notes:
Virgin Valley, Humboldt County Nevada. “Some 16 million years ago the Virgin Valley was formed during a series of rhyolite volcanic flows, resulting in a large basin enclosed by low hills. This basin contained a succession of lakes and forests of spruce, hemlock, birch, chestnut and even sequoia which were periodically buried by volcanic ash hundreds of feet thick. A large lake formed within the basin which deposited large amounts of diatomite, a biogenic form of silica. Seepage of super-heated water percolated through the ash layers, carrying silica to the long-buried trees.” This resulted in the slow creation over time of world famous opals, The Virgin Valley opals being one of just a few places in the world for famous opals, the others being Australia and Ethiopia.
Unfortunately, unlike the Aussie ones, most of those found in the Virgin Valley must be be kept submerged in water or they will “craze” or crack. Also some of these opals, possibly more than a third, are radioactive, esp. the pale green ones.
You did not dissuade Jim Bullis about anything. He just does other things so is not immediately here to deal with argumentative statements that seem to rely on deliberate misreading.
Your assertion that people come up short on food due to industrial farming methods leaves a lot undefined. I intended a make a more specific statement referring to the use of corn to make ethanol as a motor fuel as being a harmful diversion of feed grains from the food chain. You certainly can not challenge that.
I certainly am trying to introduce a new way to do farm labor with a machine I am developing. If you took a moment to watch the youtube video I linked to, you would realize the machine is oriented to increasing the role of hand labor in farm operations, which is certainly not an industrializing trend. The machine here is designed to make the work less injurious to workers, and would thus tend to enable significant expansion of agricultural operations. Type Miastrada Dragon on the youtube search line to see it.
Hank, Jim (168, 172,176,181)
This was a great question. It turns out that we have estimates of the global ice volume – using the oxygen isotope ratios of the foraminfera that lived in the deep sea. The oxygen isotope ratios record how much water is locked up in ice on land globally. Sea level reconstructions are also useful as you mention. Spatial reconstructions of where the ice was, are another question and the answers are more elusive. People are working on these questions though, as although hard problems, they are important ones to solve.