Unforced Variations: Oct 2013

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— group @ 1 October 2013

This month’s open thread. We’re going to guess that most of what people want to talk about is related to the IPCC WG1 AR5 report… Have at it!

Comments (286).

286 Responses to “Unforced Variations: Oct 2013”

251

Hank Roberts says:

27 Oct 2013 at 12:28 PM

http://rabett.blogspot.com/2010/03/simplest-explanation.html

Each part of the Earth’s surface emits heat in the form of infrared (IR) radiation. The peak of this emission is right at the wavelength where CO2 absorbs strongly. While the proportion of CO2 in the atmosphere is small, 380 parts per million or 0.038%, this is still a large number of molecules, large enough that near the surface, at wavelengths where CO2 absorbs, the average distance light will travel before being captured is a few meters (a couple of yards).

Greenhouse gases, as well as absorbing IR radiation, emit it. In just the same way the distance that the emitted radiation can travel is short near the surface, but increases as one climbs through the atmosphere because density, pressure and temperature decrease as we climb. Each of these lengthens the distance radiation emitted from a molecule travels before being absorbed,** until about at 10 km altitude where the temperature is -50 C (or ~-60 F or~220 K) and the density has decreased by a factor of ~3, it becomes possible for it to reach space, carrying thermal energy away from the Earth. Below that level, energy emitted by a greenhouse gas molecule is soon absorbed by another relatively nearby one. Thus the energy simply cannot be radiated to space to balance the incoming solar energy.

Decreasing temperature slows down the rate at which each molecule can emit while decreasing density means there are fewer greenhouse gas molecules available to absorb or radiate the energy.

Taken together this means that the doorway to space is very narrow at wavelengths where CO2 can absorb. Since the same amount of energy has to be radiated to space as is coming from the sun, something has to increase, and that is the temperature of the surface. As the surface warms, the rate at which it can radiate energy increases, pushing more thermal IR radiation out into space.

If we increase the proportion of CO2 in the atmosphere, the level at which energy can be radiated to space rises also, but since this higher level is colder and the pressure and density are lower, the doorway becomes narrower, and the surface has to warm more in order to shove the same amount of energy out and restore the balance with the incoming energy carried by the sunlight.
252

Hank Roberts says:

27 Oct 2013 at 2:01 PM

> some energy escapes the planet as reflected light.
> Is it negligible relative to the LWIR or part of it?

Albedo
253

Hank Roberts says:

27 Oct 2013 at 3:39 PM

> which of the working hiatus theories

There’s a list?
254

Patrick 027 says:

27 Oct 2013 at 7:28 PM

re 250 Walter Manny – solar radiation is mostly SW (shorter than 4 microns, or something like that), and is distinguishable from LW radiation emitted from the Earth (surface or atmosphere) for that reason (Of course, it also has a rather different spatial-temporal distribution, peaking from clouds where OLR would dip, limited to dayside, etc.). ~ 30% of solar radiation is reflected; since the 70% absorbed must be balanced by OLR (outgoing LW radiation) at equilibrium, OLR flux will tend to be 7/3 of the reflected SW flux (global time average).

(PS TOA temperature doesn’t generally match that of OLR; OLR sources are distributed through the atmosphere and some does come directly from the surface (cloud free regions, not too humid near surface, between ~8-12 microns). Absent direct solar heating, TOA approaches a skin temperature that is colder than the effective emitting temperature for the broadband OLR flux – at least, if there isn’t a particularly special distribution of different greenhouse gases at different heights with different spectra.

I assume Ray Ladbury’s description was specific to the simplified energy balance model (?))
255

Hank Roberts says:

27 Oct 2013 at 10:10 PM

Phenology continues to be news:

http://onlinelibrary.wiley.com/doi/10.1111/gcb.12283/abstract
TI – Large-scale variations in the vegetation growing season and annual cycle of atmospheric CO2 at high northern latitudes from 1950 to 2011
JO – Global Change Biology
UR – http://dx.doi.org/10.1111/gcb.12283

… During the last three decades, the thermal potential growing season has lengthened by about 10.5 days (P < 0.01, 1982–2011), which is unprecedented in the context of the past 60 years.

The overall lengthening has been stronger and more significant in Eurasia (12.6 days, P 0.05).

The photosynthetic growing season has closely tracked the pace of warming and extension of the potential growing season in spring, but not in autumn when factors such as light and moisture limitation may constrain photosynthesis.

The autumnal extension of the photosynthetic growing season since 1982 appears to be about half that of the thermal potential growing season, yielding a smaller lengthening of the photosynthetic growing season (6.7 days at the circumpolar scale, P < 0.01). … when integrated over the growing season, photosynthetic activity has closely followed the interannual variations and warming trend in cumulative growing season temperatures.

This lengthening and intensification of the photosynthetic growing season, manifested principally over Eurasia rather than North America, is associated with a long-term increase (22.2% since 1972, P < 0.01) in the amplitude of the CO2 annual cycle at northern latitudes.

The springtime extension of the photosynthetic and potential growing seasons has apparently stimulated earlier and stronger net CO2 uptake by northern ecosystems, while the autumnal extension is associated with an earlier net release of CO2 to the atmosphere. These contrasting responses may be critical in determining the impact of continued warming on northern terrestrial ecosystems and the carbon cycle.

—-
extra (that is, all) paragraph breaks in the above block quote have been added to the original big-hunk’o’abstract, for screen readability — hr
256

Ray Ladbury says:

28 Oct 2013 at 5:00 AM

Walter, your first question concerns what scientists call albedo–the fact that Earth reflects some of the incident light at whatever wavelength. Reflected light never really enters the system. However, changes in albedo can change the energy balance. That is one of the big long-term feedbacks.
2)It is inescapable that increased CO2 must increase temperature. No credible scientist disagrees on this. They merely argue about the amount of warming. Since CO2 is taking a chunk out of the outgoing IR, then the initial amount of outgoing LWIR must increase to compensate for the chunk taken out. The only way LWIR increases is to increase radiating temperature. Most geoengineering palliatives rely on increasing albedo so that less SWIR is absorbed, so that would be one way to avoid the temperature increase in the short term. However, these efforts would likely not be sustainable on a timescale of centuries due to cost and side effects.

3)It is very much early days when it comes to understanding internal variability. We are not even sure whether the amount of variability would increase itself as the temperature warms (some of the ocean work hints in that direction). If that were the case, then a 15 year “hiatus” might not be unusual in the future. In my opinion, the escalator structure of warming is begging for a multi-box solution, probably involving an increased role for the mid-to-deep ocean Most indications are that relative humidity doesn’t vary all that much, so I have my doubts about “reduced atmospheric water vapor”. I would point out, though, that if this is a contributor, we are really in the soup, as it means drought is going to be a much bigger problem going forward.

Finally, I stress that I am no expert in this field–merely an interested amateur. I trust Gavin et al. will weigh in if I’ve said something stupid.
257

Ray Ladbury says:

28 Oct 2013 at 5:05 AM

Patrick027,
Yes, I’m dealing with a very stripped-down model, and when I’m talking about TOA equilibrium, I am not assuming that all radiators are at TOA. I am not even assuming that TOA is an isobar or the same at all wavelengths. I’ve found that the multi-box model is a useful, wrong model for illustrating the basics.
258

Radge Havers says:

28 Oct 2013 at 10:13 AM

In the news. Getting at catastrophe?

Universal rules discovered that allow anticipation of critical transitions

At first glance, it appears improbable that a climate shift, an epileptic seizure, the collapse of a fish population or a sudden transition in a financial system have something in common. However, the article in Science, a consortium of scientists headed by Marten Scheffer from Wageningen University, part of Wageningen UR, shows that completely different systems – such as the brain, the climate and financial markets – obey certain universal laws when they are at a critical transition point that make it possible to recognise early warning signals. This has to do with a phenomenon that is known in mathematics as ‘Critical Slowing Down’, implying that recovery from small perturbations becomes slow in the vicinity of tipping points.

http://phys.org/news/2012-10-universal-critical-transitions.html#nRlv
259

Hank Roberts says:

28 Oct 2013 at 10:31 AM

Hat tip to Slashdot:

… the National Institutes of Health has launched a project to remake its researchers’ approach to publication. Its new PubMed Commons system allows qualified scientists to post ongoing comments about published papers. The goal is to wean scientists from the idea that a cursory, one-time peer review is enough to validate a research study, and substitute a process of continuing scrutiny, so that poor research can be identified quickly and good research can be picked out of the crowd and find a wider audience. ‘The demand for sexy results, combined with indifferent follow-up, means that billions of dollars in worldwide resources devoted to finding and developing remedies for the diseases that afflict us all is being thrown down a rathole,’ says Hiltzik. ‘NIH and the rest of the scientific community are just now waking up to the realization that science has lost its way, and it may take years to get back on the right path.'”
260

Walter Manny says:

28 Oct 2013 at 10:35 AM

Thanks, Ray, and I’m sorry I can’t recall where it was I read or heard about relatively low concentrations of water vapor being of potential interest to hiatus explorers, among other things such as sunspots and, more intriguing, deep ocean. Thanks for your time and your willingness [lame humor alert] to think outside the multi-box. Better equipped, I’m going to have a crack at Xie & Kosaka now, see if I can grok some of it…
261

Hank Roberts says:

28 Oct 2013 at 10:39 AM

apropos ongoing comments and discussion among scientists, the biologists are continuing to make effective use of Usenet:

IOSCI/Bionet is a set of electronic communication forums – the bionet USENET newsgroups and parallel e-mail lists – used by biological scientists worldwide. No fees are charged for the service.

BIOSCI promotes communication between professionals in the biological sciences. All postings to the newsgroups should be made in that spirit. While the general public may “listen in” to the discussions, these newsgroups are intended primarily for communications between researchers. There are other forums on Usenet such as sci.bio.misc for the asking and answering of biological questions from lay persons.

There’s a lot to be said for the old Usenet (and before that FIDOnet) approach: text-only, slow, not easy to choke off.
262

Hank Roberts says:

28 Oct 2013 at 4:06 PM

I’ve been wondering why the two climate scientists associated with their respective Navy submarine operations are on record expecting the Arctic sea ice to go away sooner.

It makes sense to me logically that they could have access to information that’s kept secret — and be able to disclose conclusions but not the reasoning.

EOS for 8 October 2013 in their brief back page items (p. 372) mentions

Dokken et al., Paleoceanography, doi:10.1002/palo.20042, 2013

which suggests the past record of extremely fast Greenland temperature increases (“DO events”) could be caused by a breakdown of the layering of Nordic seas: sea ice, then cold fresh water, then below that salt water — and the salt water is circulating so when warmer ocean water moves into that area it first replaces cold bottom layer salt water. Eventually it “breaks the halocline” and the warmth reaches the sea ice, which disappears.

So where’s the halocline, and is it changing?

Well, ask the submariners (and check whatever can be told or inferred from data collected by the no doubt extensive secret monitoring gear the nuclear-capable Navy departments must have spread all across the Arctic ocean over the past 40 years).

I know submariners use the halocline — and any other difference in water salinity or density — to hide, and to channel sound. So do whales and dolphins, of course. But if anyone’s able to ask them, it’d be the Navy.

(Decades ago when I was a marine biology student, a lecturer told us how all the various marine biology labs got their echo-sounding equipment from their countries’ Navy people, and the gear given the scientists had cut-outs to prevent them from working in the frequencies useful for detecting submarines. But each of the nations had cut out different bands, so the marine biologists would get together annually and trade records to fill in the gaps in their pictures)
263

Hank Roberts says:

28 Oct 2013 at 5:07 PM

http://www.bbc.co.uk/news/science-environment-17129988

23 February 2012
UK submarine data de-classified to aid climate science

A dataset from one submarine mission will be released to give a snapshot of conditions under the ice.

… Water temperature and salt content are among the environmental data monitored by submarines.

But only a handful of people have access to such information because they could be used to track where UK submarines go.

As part of the Submarine Estimates of Arctic Turbulence Spectra (SEATS) project, the MoD will release measurements to researchers at the National Oceanography Centre (NOC) in Southampton.
264

Hank Roberts says:

28 Oct 2013 at 5:12 PM

15 years ago, autonomous undersea vehicles were laying cable under the ice:
http://www.sea-technology.com/features/2013/0513/6_AUVs.php

The Theseus program began at ISE in 1985 as part of a Canada-U.S. program to lay cable under Arctic ice. ISE and the Defence Research Establishment Pacific (DREP) of Canada’s Department of National Defence worked together to develop a large AUV for laying cable from a site near the shore of Ellesmere Island in the Canadian Arctic to a scientific acoustic array in the Arctic Ocean about 200 kilometers from shore. Two under-ice cable-laying missions were conducted from Ellesmere Island in 1996 in water depths that varied from 50 meters at the launch site to about 600 meters at the array site….
265

wili says:

28 Oct 2013 at 5:30 PM

Interesting comment, Hank (@ #258). But which two scientists exactly were you referring to here: “the two climate scientists associated with their respective Navy submarine operations”
266

Hank Roberts says:

28 Oct 2013 at 9:59 PM

Maslowski and Wadhams

‘oogled, plenty available, e.g.

http://www.annualreviews.org/doi/full/10.1146/annurev-earth-042711-105345

Apr 29, 2012 – Wadhams, P., N Hughes and J Rodrigues (2011). Arctic sea ice thickness characteristics in winter 2004 and 2007 from submarine sonar …

Just sayin’ — I have to wonder how much more data the Navies of the planet have accumulated, over 50 years of travel and stationkeeping under the Arctic ice.
267

Kevin McKinney says:

29 Oct 2013 at 8:40 AM

#265 & 266–Yes, Dr. Wadhams has done research from aboard one (or more? I don’t know a lot of detail on this) of Her Majesty’s nuclear subs cruising under the Arctic sea ice. Perchance he may have had something to do with the release of the UK data? (Pure speculation on my part.)
268

Hank Roberts says:

29 Oct 2013 at 10:13 AM

Yeah. And if there’s a trend — the Navy will know about it.
They have more data than what’s being released. As quoted above:

A dataset from one submarine mission will be released to give a snapshot

Well, duh. Not much of a trend can be calculated from that.

And if this paper is right, and the D-O warming events are explained as they suggest, prepare for the surprise when it happens.

You can find the paper, just ‘oogle the name and look for a copy that’s not paywalled.
https://www.google.com/search?q=Dokken+et+al.%2C+Paleoceanography%2C+doi%3A10.1002%2Fpalo.20042%2C+2013
269

wili says:

29 Oct 2013 at 1:42 PM

Thanks, Hank. I think that is an important consideration. I hope you don’t mind if I share it on other sites (properly attributed, of course).
270

Hank Roberts says:

29 Oct 2013 at 3:06 PM

Eh? I’d wait on the climate scientists to opine
eventually. You’ll have noticed there are several different kinds of inference in that paper from proxies. These new ideas need to be kicked around a bit. Don’t assume the conclusion — which is clearly a suggestion of a new idea — is correct.
271

Hank Roberts says:

29 Oct 2013 at 5:33 PM

I found a bit of history, a reminder that typically that kicking around a new idea is well underway before publication:

http://www.bjerknes.uib.no/filer/2169.pdf‎

DIRECTOR’S NOTE Sep 16, 2013 – … the Dokken et al. paper on. D-O Events out now in Paleoceanography, which in my opinion gives a novel and convincing explanation for abrupt climate changes…. is finally out after various versions and problems with biased reviews. Thanks to the author team of modelers and observationalists on keeping the process going….”
272

Nigel Williams says:

30 Oct 2013 at 3:02 AM

If I may put it politely; ‘We’re screwed.’
http://criticalangleblog.files.wordpress.com/2013/10/jaccard-peak-oil-chap-in-homer-dixon-carbon-shift-20091.pdf

Figure 4. 1000 billion barrels of oil used to date. Over 10,000 billion barrels still available at less than $50.00 a barrel.

Any questions?
273

wili says:

30 Oct 2013 at 10:37 AM

Nigel, I’m too busy too read it right now, but if there is that much cheap oil around, why isn’t the price of oil already well below $50/barrel. Are they really that good at price fixing? Isn’t it a bit…difficult to artificially fix the price of anything at a global level and make it stick for year after year?

But your conclusion is, none-the-less, almost surely right.
274

wili says:

30 Oct 2013 at 4:01 PM

To clarify ‘conclusion’ I meant the quoted bit about the nature of our screwedness.

Hank, ok, I’ll include that caveat. Thanks for the insight.
275

Nigel Williams says:

30 Oct 2013 at 5:13 PM

wili, I think the paper is saying that there are viable ways to produce oil at prices we have shown we can afford for a while yet. Mainly Gas to Liquid (x fracked natural gas, for example (ignoring the short future of fracked wells)) and Coal to Liquid that is being /has been done by China, South Africa and wartime Germany, among others. And there is a lot of coal good and bad out there still.

So the ‘race’ between the curves is that there is clearly a depleting natural oil resource of finite size and increasing extraction cost, while there is another curve which represents the construction of sufficient Gas and Coal to Liquid capacity to replace the falling natural supply.

If the natural supply issues crash the economy before the x-liquid capacity is built, then we loose the opportunity to transfer to the x-liquid option.

All of which goes to extend the business-as-usual burn of carbon from increasingly bad sources which will only reduce the chance of effective reduction of GHG emissions and avoidance of climate catastrophe.

As a peak-oiler of old its hard for me to accept that the x-liquid option could offer a continued supply for a while yet if (and that’s the big IF) sufficient x-liquid capacity is built fast enough. But the idea of peak oil was an attractive way to see a major wind down in emissions forced upon us.

However (as the recent Do the Math work has shown us too) there is far more carbon readily available at viable prices that we should ever burn. So it seems that resource depletion will not be of much assistance to the climate battlers, and instead we will have to rely virtually entirely on social and political measures to reduce emissions and keep the climate from tipping over a very nasty edge.
276

sidd says:

30 Oct 2013 at 5:46 PM

Any new results from GRACE on 2013 Greenland melt ? Some came out about this time last year …
277

Jim Larsen says:

30 Oct 2013 at 5:52 PM

273 wili wondered about oil prices.

Yes wili, they are that good. The most expensive oil today is tar sands, at about $25 a barrel.
278

sidd says:

30 Oct 2013 at 8:23 PM

Mr. Jim Larsen wrote: ” … tar sands, at about $25 a barrel.”

This is, as I recall, a Syncor estimate of operating cost, which does not include capitalization cost for the facilities (which in Syncor’s case is paid off.) If one were to include cap costs for a new facility, the number was around $60-$70 a few years ago, and more now, since the risk of unburnable reserves is recognized by the banks …

sidd
279

wili says:

30 Oct 2013 at 8:34 PM

Thanks, all. But it still seems to me that if there were lots of oil out there right now that could be produced at about half what the current market price is, it would be getting produced now already in massive amounts. But, asfaik, there is very little coal-to-liquid gas being produced nor shale oil.

But of course price is a pretty fungible thing. If we go through another global financial crisis and the price of everything crashes, oil prices will likely follow suit, wherever it comes from. It is the number of people who still have jobs to afford the oil/gasoline at any price that will change.

Jim, I hadn’t seen that price for tar sands oil, but I haven’t been following the industry as closely as I used to. Do you have a source for that figure? Is that just on-site production, or the final price once it has been shipped and processed?

I’ve never been one to believe that peak oil would save us. But I have been surprised at how viable very low EROEI oil like tar sands ended up being.

And yes, screwed we all almost definitely are.
280

flxible says:

31 Oct 2013 at 9:29 AM

Find some discussion of tar sands production costs here – not as “cheap” as Jim suggests, but it’s still profitable.
281

SecularAnimist says:

31 Oct 2013 at 10:15 AM

Nigel Williams wrote: “Over 10,000 billion barrels still available at less than $50.00 a barrel.”

Jim Larsen wrote: “The most expensive oil today is tar sands, at about $25 a barrel.”

Where are these numbers coming from?

Bloomberg Energy is showing crude oil spot prices at $96.25/bbl (WTI) and $108.90/bbl (Brent).

http://www.bloomberg.com/energy/

The US Energy Information Administration has similar figures:

http://www.eia.gov/dnav/pet/pet_pri_spt_s1_d.htm

And the Wall Street Journal reports that “Light, sweet crude for November delivery settled 1.6%, or $1.56 lower, at $96.77 a barrel, the lowest price since June 28.”

http://online.wsj.com/article/BT-CO-20131030-713579.html
282

Nigel Williams says:

31 Oct 2013 at 4:24 PM

SecularAnimist, my point is based on the paper I quoted.

As I’ve commented above, its well-proven technologies like coal to liquid that are the potential game-changers.

South Africa and a few others have been operating with coal to liquids producing significant proportions of their liquid fuel supplies for many years when oil was in the $10 to $40 a bbl range. There is an awful lot of coal out there (down to horrible lignite) that still that can be converted to liquids using that process.

The result of this appreciation is of course merely another confirmation that humanity has economically viable access to liquid fuel resources for some time to come.

The take home point really is that – as Bill McKibbon and others have reminded us – we have to configure the planet socially, politically and promptly so that virtually all of the remaining carbon is left in the ground unused for a very long time.

There is really nothing else to do that’s relevant. We have enough information to make that decision. All the measuring and reporting that’s going on now is great, but the evidence is already way past the tipping point.

Our global effort now has to be focused on the ways and means of halting our impact on our global climate before it too passes a tipping point beyond which neither we humans or the biota upon which we depend for our lives can survive.

And of course it has to start ‘at home’, to lead by example, otherwise we have no moral ground to preach change from at all. Which is why I am fixing up an old house (rather than building new) and busily planting the shelter belts and vegetables on half a hectare of land we own on a site that is as close as we can find to being on the cusp of wetter/dryer climate conditions as predicted by IPCC et al. There we are aiming for a high level of self-reliance and very low carbon footprint. Only when I’m established there will I have a platform to preach change from to those who still see the ‘Western Way’ as being ‘progress’.
283

Patrick 027 says:

31 Oct 2013 at 6:19 PM

re 257 Ray Ladbury – thanks; I tend to think of TOA as being p = 0, which of course doesn’t exist *, but it’s a useful approximation, to put a definite upper bound on the atmosphere.

(* actually I’m not entirely clear on what’s going on way up there, in so far as … if pressure is no longer isotropic at some point due to the magnetic field ? … do they assign an isotropic component and call the other terms tensile and shear stresses (and would they be different between electrons and protons, and He++,…)? Would that make any sense? Fortunately I don’t need to know to discuss the energy balance of the climate.)

re 260 Walter Manny – changes in stratospheric water vapor

older (2010):
http://www.wunderground.com/blog/JeffMasters/stratospheric-water-vapor-decline-credited-with-slowing-global-warming (question posed – a negative feedback? limited data isn’t clear) also, http://www.sciencedaily.com/releases/2010/01/100131145840.htm\

newer (2013):
http://www.pnas.org/content/early/2013/09/26/1310344110 (more recent – says it’s a positive feedback.) Also http://www.sciencedaily.com/releases/2013/09/130930161525.htm

(Well, if it’s possible for a brightening sun hundreds of millions of years from now to dry out the oceans because so much H2O is getting into the upper atmosphere and breaking up by UV… OTOH, CO2 greenhouse forcing cools the stratosphere. Would this positive feedback be stronger for solar forcing? Would the FAT feedback be less strong for solar forcing?)

re oil price –
considering only the cost of ongoing production makes sense in the context of figuring out what the lowest price could be before the oil company throws in the stinky inky greasy towel – if they sold it for less they’d be losing money in proportion to production. But only selling it for that much still represents a loss because of capital costs and stuff I don’t know about. So prices shouldn’t come down to that unless they get desperate.

Production rates are limited by infrastructure in place (capital) … and by long term goals – I’ve read several years ago that pumping oil out too fast reduces the amount that can ultimately be extracted. Whether newer technologies change that picture, I’m not sure)

It occurs to me that the capital cost portion of the price paid for a barrel of oil isn’t necessarily assignable to the capital costs that went into that barrel – some of it could be for the next barrel. In that case, prices should decline if exploration, etc, slow down or halt (considering that effect in isolation, of course).
284

Patrick 027 says:

31 Oct 2013 at 6:27 PM

PS there’s a new series on The Weather Channel, “Tipping Points”
http://www.weather.com/tv/tvshows/tipping-points/main
285

Hank Roberts says:

31 Oct 2013 at 7:53 PM

http://onlinelibrary.wiley.com/doi/10.1002/grl.51011/abstract

Notes that usually the ocean end of a glacier is floating over a layer of cold fresh meltwater, which in turn is floating on top of warmer salty ocean water.

Then what happens?

Rapid submarine melting driven by subglacial discharge, LeConte Glacier, Alaska
Geophysical Research Letters
Volume 40, Issue 19, pages 5153–5158, 16 October 2013
http://onlinelibrary.wiley.com/doi/10.1002/grl.51011/abstract
DOI: 10.1002/grl.51011

Having read only the abstract, I paraphrase:

Rainfall on glacier
Increased outflow of fresh meltwater, and
for a glacier ending at the ocean, fresh is floatier than salt water, so
the fresh water flows out out along the bottom of the ice, and below that is warmer seawater
and with the flow of fresh water moving fast along the ice,
the warmer sea water gets pulled up (entrained) and mixes in,
so that makes contact with and warms the bottom of the ice.
286

Doug Bostrom says:

31 Oct 2013 at 11:32 PM

“…tar sands, at about $25 a barrel.”

Cost to produce, not buy.

Unforced Variations: Oct 2013

286 Responses to “Unforced Variations: Oct 2013”

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