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The debate is just beginning — on the Cretaceous!

Filed under: — raypierre @ 23 January 2008

Most of us who are involved in research related to climate change have been asked at one time or another to participate in public debates against skeptics of one sort or another. Some of us have even been cajoled into accepting. In the pre-YouTube days, I did one against the then-head of the American Petroleum institute at the U. of Chicago law school. Gavin did an infamous one against Crichton and company. People are always demanding that Al Gore debate somebody or other. Both Dave Archer and I have been asked to debate Dennis Avery (of “Unstoppable Global Warming” fame) on TV or radio more than once — and declined. It’s a no win situation. If you accept you give the appearance that these skeptics have something to say that’s actually worth debating about — and give their bogus ideas more publicity. If you decline there are all sorts of squawks that “X won’t debate!” or implications that scientists have declared “the debate” (whatever that is supposed to mean) prematurely closed when in fact it is “just beginning.”

Scientists tend to react badly to demands like this in part because the word “debate” is a rather poor description of the way disagreements get hashed out in science. John Ziman has a good discussion of the extent to which scientific questions are ‘debatable’ here (pdf). In a lawyerly debate, it is fair game for each side to pick and choose whatever argument has the most persuasive force with the audience, jury or judge, without any obligation to consider the force of counter-arguments except insofar as they affect one’s defense against the opponent. Science, in contrast, is a deliberative, cooperative, yet still competitive enterprise, where each side is duty bound to fairly consider all arguments and data that bear on the matter at hand. This is not to say that scientific disputes are necessarily dispassionate or orderly. Indeed, I’ve seen near-fistfights break out over things like the Snowball Earth and the interpretation of Neoproterozoic carbon isotope excursions.

The repeated challenges to debate are probably meant to imply that scientists — and their supporters, including Al Gore — are fixed in their ideas, unreceptive to the new and challenging, and unwilling to defend their ideas in public. This picture is hard to square with how scientists actually behave among themselves. It is not that scientists don’t debate, dispute, disagree about matters related to climate. All those things happen, but not on the subjects that skeptics like Inhofe or Fred Singer or Dennis Avery would like to debate (like whether global warming is mainly caused by CO2 or solar variability, or whether the IPCC warming forecasts represent a credible threat.). Those sorts of things are indeed considered settled science by serious climate scientists. Then, too, scientists are justifiably wary of being drawn into staged debates on such diffuse, ill-defined and largely meaningless topics as whether global warming counts as a “crisis.” In the war of the sound bites, the people who feel free to lie and distort can always win. David Mamet made this point eloquently in Bambi vs. Godzilla. A debate like that is not any kind of debate in the sense understood by scientists.

In fact scientists are probing theories and conceptions all the time, trying to break them. The best way to become famous is to overturn established wisdom, so scientists look hard all the time for opportunities to do this. The problem of Hothouse climate states like the Cretaceous and Eocene is a case in point.

The Cretaceous is the time period from 145 million years ago up to the demise of the dinosaurs about 65 million years ago. The Eocene is a more recent period, from 56 million years ago to 34 million years ago. In between is the Paleocene, which is generally somewhat cooler than the late Cretaceous or mid Eocene. It has long been known that the polar climate — particularly the Arctic climate — was very different from today’s. Many lines of evidence indicate temperatures well above freezing, with little or no permanent land ice and infrequent or absent sea ice. Lemurs could live in Spitzbergen, and crocodiles on Hudson Bay, to name a few examples. Most evidence also points to an absence of ice in Antarctica as well. These Hothouse (or Super Greenhouse) climates have much warmer polar regions than is the case for today’s climate, and winters were evidently very mild. These hothouse climates are idealized as having been almost completely free of significant ice sheets on land and sea ice cover in the ocean. Hothouse climates pose a challenge to our understanding of climate in general, but more particularly they serve as a critical clue as to what surprises a high-CO2 world might have in store for us.

This is so because, at present, the only viable theory for Hothouse climates is that they come about as a result of elevated CO2 concentrations, which in turn are due to long term changes in the Earth’s carbon cycle. The CO2 theory has many problems, some of which I’ll discuss below, but no theory without elevated CO2 has been able to even come close to accounting for the Hothouse states. These climates would be just dandy as a natural test of the Earth’s sensitivity to long lived greenhouse gas concentrations were it not for one nasty fact: it is very, very difficult to get an accurate idea of how high the CO2 concentrations were so far back in time (see Crowley and Berner or Broadly Misleading on RC). For example, estimates for the Eocene range from values similar to modern CO2 concentrations all the way up to 15 times pre-industrial CO2. This unpleasantly large range represents uncertainties in the proxies used to estimate CO2 in the distant past. Various general circulation models can achieve largely ice-free polar conditions with CO2 between 4 and 8 times present concentrations, though even at those levels there are difficulties in accounting for the mildness of the winters. And up until recently it was thought that the tropical temperatures in such simulations were far warmer than reality — but more about that anon.

In the past few years there has been a real shake-up in the conception of what hothouse climates are like. First, it was found that the Tropical regions in hothouse climates are not tightly thermostatted as had been previously thought. Prior indications of a cool tropics turned out to be an artifact of alteration of the chemistry of marine sediments after they were deposited — a nightmare known as diagenesis to paleoceanographers. The tropics are actually quite a bit warmer than today’s tropics. For example, the Eocene tropical ocean may have been as warm as 35C, as compared to about 29C today. The upward revision of tropical temperatures is quite a good thing for the CO2 theory, since it removes a good part of the “low gradient” problem, wherein models were thought to systematically exaggerate the pole to equator temperature gradient.

So far, so good. But then, just last year through heroic efforts involving a nuclear icebreaker, a conventional icebreaker and an icebreaking drill-ship. a deep-time sediment core was recovered from the Arctic ocean. The results, which came out in a series of papers in Nature (here,here and here) were startling. At times the Arctic was practically a freshwater lake, indicating some quite dramatic changes in the hydrological cycle. And more germane to the matter at hand, in the early Eocene, the Arctic was much warmer than previously thought. According to Sluijs et al ocean temperatures were as high as 23C — rather like Key West today. These temperatures come to you courtesy of a novel biochemical proxy known as Tex86, derived from certain lipids produced by tiny plankton called Crenarchaeota. Tex86 is the new wunderkind of paleoceanography.

Will wonders never cease? Evidently not. Just when the hothouse starts looking really, really hot, along comes a new Science article by Bornemann et al, dealing with climatic conditions in the Turonian (93.5 to 89.3 million years ago). The principal result of this paper is that there appears to have been a 200,000 year period right smack in the middle of one of the warmest periods of the past half billion years, when there were ice sheets (presumably in Antarctica) that were up to 60% the volume of today’s Antarctic ice sheets. How in the world do you get such large ice sheets in a high CO2 climate warm enough for crocodiles to survive in the Arctic at the other side of the planet? And this apparent glaciation is not the result of a global cold snap. As in the Eocene results quoted earlier, the tropical ocean surface temperatures are again on the order of 35C — courtesy once more of the wondrous Tex86 proxy.

How was the ice volume inferred? Primarily by an especially meticulous application of an old technique. When a glacier forms on land, the water it is made of is enriched in the lighter form of oxygen, 16O, which leaves the ocean enriched in the heavy form, 18O. Single-celled shelly creatures called foraminifera (“forams” for short) record this composition, but they are very subject to diagenesis. The key to the new estimate was to take samples from pristine glassy portions of exceptionally well-preserved foram shells. The sample was taken from a core in the Tropical Western Atlantic, so the investigators are able to determine tropical surface temperatures, making use of Tex86 proxies from organisms living near the surface. The ocean water isotopic composition is estimated using both surface-dwelling and deep-dwelling forams.

Since the oxygen isotope composition of forams depends on temperature as well as ocean water composition, the Tex86 proxy was used to correct for the temperature effect in forams living near the surface. There is no independent temperature proxy for the deep ocean, but the investigators assumed (a bit questionably) that deep ocean temperature did not change much over the time period. Be that as it may, the deep ocean oxygen isotope shift (uncorrected for any temperature effect) was similar in magnitude to the estimate from surface forams. Once you have the oxygen isotopic composition of sea water, you can translate that into ice volume by making an estimate of the isotopic composition of glacier ice. All this is easier said than done, but they did it. The glacial interval corresponds to the excursion of delta-18O toward positive values in the figure below, taken from the paper:

There is a useful commentary by Richard Kerr One must exercise the usual caution we urge in connection with radical results, and await confirmation before taking it to the bank. As Kerr points out, there is other data from this time period that doesn’t show the isotope shift.

There are two additional things I myself noticed, which seem inconsistent. The first is that in order to get reasonable numbers for ice volume, the investigators needed to assume that Antarctic ice in the Cretaceous period had the same isotopic lightness as Antarctic ice today. Most theories of fractionation would have Antarctic ice being less fractionated in a warm climate, however. Perhaps the high Equator to Antarctic gradient helps keep the Antarctic ice light, but this is something that needs to be checked. What’s even more troubling to me is that the bottom-dwelling forams (uncorrected for temperature) indicate the same ocean water isotopic shift as the temperature-corrected surface dwelling forams. However, if Antarctica glaciates, the deep ocean should be filled with cold Antarctic bottom water, which should produce an additional positive isotopic shift in the uncorrected bottom dwelling forams. That this shift isn’t seen suggests that something is amiss to me.

Still, this paper already has a lot of modelers scratching their heads. To give an example of the magnitude of the problem, I reproduce below a figure from one of Rob DeConto’s old simulations (Nature 421, (2003) ), showing the glacier distribution in Antarctica as a function of CO2, as CO2 is steadily decreased. These are done for orbital parameters favorable to Antarctic glaciation; the simulations don’t use Late Cretaceous geography, but they do give a good idea of how hard it is to get a big glacier in Antarctica with anything much above twice the preindustrial CO2.

It is salutary to keep in mind that in many past cases where data conflicted with robust modeling results, it turned out to be the models that were right and the data that was wrong. This was the case for the early satellite reconstructions of twentieth century lower tropospheric temperature, which showed a spurious cooling. It was also the case for early reconstructions of tropical climate during the Last Glacial Maximum, which failed to show the cooling we now know to prevail in that region during glacial times.

So, what does all this mean for CO2 and anthropogenic global warming? Does it mean we don’t know beans about climate, so let’s have a party and why worry? No, actually. All this hothouse strangeness gives us a great deal more to worry about. The tropics is not strongly thermostatted, and there appear to be feedbacks in the system that can amplify polar warming more than previously thought possible. Perhaps due to clouds? Matt Huber, one of the foremost Eocene modellers, stated in a recent seminar at the University of Chicago that he could get closest to reproducing the Eocene hothouse by assuming that the Earth’s real climate sensitivity is at the high end of the IPCC range — around 4C per doubling of CO2. Or, perhaps there are mode switches in the climate system we know nothing about, which we are risking triggering by increasing CO2. Without understanding the Hothouse climates, it’s impossible to say how close we are to the danger zone.

But what of this new riddle of Cretaceous ice? An optimist might say that the result shows that you can keep a lot of ice in Antarctica even in a very warm climate. On the other hand, the conditions allowing the ice to exist in a warm climate are evidently very fragile, since it was there (assuming the result holds up) for only 200,000 years — the wink of an eye, in geological terms. That could mean that the factors governing whether Antarctic ice stays or goes in a warm climate are more subtle than we thought, offering more possibilities for surprise transitions. Or it may turn out that Cretaceous CO2 is really only twice the pre-industrial level, but that there’s some whopping positive feedback which bumps up tropical temperatures to 35C. In a scenario like that, the strange and unexplained resistance of Antarctica to warming might save some Antarctic ice, but that would be cold comfort, since the rest of the world would be toast.

Or, it may turn out that the processes determining the glaciation and deglaciation of a partly ice covered Antarctica have nothing to tell us about the present situation starting with a large Antarctic ice sheet. I’d be surprised if this turned out to be the case, but it could happen. One thing is for sure — if the result survives, it will provide an important and challenging test for the next generation of ice sheet models.

Could it be that the glaciation is telling us that we are completely barking up the wrong tree with the CO2 theory of hothouse climates? Perhaps, but somebody will have to pony up a quantifiable alternative before that avenue can be pursued. And whatever the alternative is, the challenge of simultaneously explaining the coexistence of a super-hot tropics with Antarctic glaciation — and also explaining why this happened for only 200,000 years — is apt to be as big as any challenge posed to the CO2 theory. One could probably get a climate something like the suggested one by combining moderately elevated CO2 with making a lot of low clouds over Antarctica while making the rest of the world essentially cloud free (or somehow making the high cloud greenhouse effect dominant in the rest of the world), but that’s quite a stretch. If somebody comes up with a way of doing that which can be expressed in a sound mathematical formulation, I’ll be the first to want to have a look at it. Cosmic ray enthusiasts could have a field day with this, but I doubt they’d have much success.

However you slice it, it starts to look like the Eocene and Cretaceous are tugging at our sleeve, whispering to us “There are things going on with climate you don’t begin to understand. Proceed with caution.”

We already knew hothouse climates were interesting, but darned if they don’t just keep getting more and more interesting. It puts me somewhat in mind of the old Yiddish curse– “May you live in interesting times.” But, to paraphrase Maurice Sendak — Let the Wild Rumpus Continue!


308 Responses to “The debate is just beginning — on the Cretaceous!”

  1. 151
    Hank Roberts says:

    You’re not the Steve Reynolds who’s chairman of Pacific Sound Energy, are you? Just curious.

  2. 152
    Walt Bennett says:

    The larger point that Steve Reynolds makes is: is the emerging world entitled to the same access to energy and productive capacity that the west has enjoyed for a century? Are we prepared to close the door on them, now that we have done so much damage that we can’t afford to let them add to it?

    I agree the Reynolds question is not defensible intellectually, but as a provocation, he has a very real point.

    One reason I consider emissions reduction DOA as a standalone strategy is that China and India (and we aren’t even discussing Africa yet!) will refuse to be left out of the development arc. Demanding that they find a “cleaner” way to advance than we did is more than a little condescending.

    Steve reveals a very important and stubborn issue.

    [Response: It's a red-herring. Energy production in India and China is much less efficient than in the US or Europe - contributing both to excessive waste and air pollution. Matching developed world standards would allow for a doubling (or more) of the energy use, with no change in emissions (and a big decrease in pollution). - gavin]

  3. 153
    Walt Bennett says:

    Re: #152 inline,

    Gavin,

    Thanks for the response. Several things: 1, “developed world standards” would still be an imposition on an emerging economy, I suspect, based on cost, or else why would they not already be doing it that way? 2, a decrease in pollution (for example, this summer in and around Beijing) would allow the AGW signal to emerge even more strongly, yes? 3, “no change in emissions” is the BAU scenario, correct? This means that we will cruise past the tipping point, yes? Getting China/India et cetera to actually reduce emissions would be necessary, circling back to Steve’s point. I suppose you could argue that greater efficiency would allow for overall emissions reduction, but has that been speced out? what are the costs and realistic timetables?

    [Response: The idea that there can't be any efficiency savings because someone would have done it already is a fallacy. Why aren't all bulbs CFL? However, it does take time and effort. Pollution in India and China is complex - there is a big component of black carbon - mainly related to inefficient coal burning - as well as sulfates and so it might be better climatically than you think. The point being that the issues are not ones of development vs. climate, but on how to manage development in effective ways. You need to talk to more knowledgable people than me on what the details are. - gavin]

  4. 154
    pete best says:

    Re #152 India and China can newer has access to as much oil as they will need as it simply does not at present exist. Gas is the same and coal is anyones guess. This is the whole idea of why war and famine and world affairs will overtake climate changes importance come 2015 to 2020, well without big new finds in oil fields which is extremely unlikely.

    Oil allows us to get at oil and coal and it is the first to peak.

  5. 155
    Ray Ladbury says:

    Walt, Let’s look at it another way: Are we going to insist that China and India destroy their environment trying to raise the living standards of 3 billion people with outdated, dirty technology? Refusing to assist them to find a “cleaner” way is more than a little condescending–not to mention foolhardy. Given that China and india are still building infrastructure there is a golden opportunity to make sure that infrastructure is as efficient as possible. That pays dividends down the line for a long while–both for China and India and for the global environment.

    We have to start looking at this as something other than a zero-sum game.

  6. 156
    Steve Reynolds says:

    Ray Ladbury> Steve Reynolds, have you been to China or India? Yes, a small elite are emerging from poverty, but at an environmental cost that is utterly unsustainable.

    Ray, yes, I have visited China 3 times over the last ten years, and have toured various factories making toys, batteries, and high tech LCD displays. The battery factory was literally a very dirty sweatshop, in contrast to the LCD facility containing modern cleanrooms.

    My impression from those visits was that your ‘small elite’ emerged from poverty several years ago, and now drive the most expensive BMWs made. A very large number of people have made it to middle class status, and a huge number are working very hard to get there. They are not letting some very disgusting pollution stop them. I think they will clean up the most unhealthy pollution as they become wealthy, just as western people did.

    I do not think anything short of war will convince them to stay poor any longer than necessary just to prevent AGW.

    Barton> Despite the constant refrain to the contrary from denialists, it is possible to deal with global warming and still have billions emerge from poverty in China and India.

    I think that it is possible, only that it will take 20 to 40 years longer. I doubt that the people there will be willing to wait. That is why I favor working on long lead technology now to reduce CO2 drastically later when it will be more affordable.

    Hank> You’re not the Steve Reynolds who’s chairman of Pacific Sound Energy, are you?

    No, I am not.

  7. 157
    Philippe Chantreau says:

    A friend of mine was recently in Shanghai. His hotel’s elevator happened to be the external type, with a view. On a day without significant weather, he could no longer see the ground past the 16th floor. He says it does get worse.

  8. 158
    Walt Bennett says:

    I know I already have a requested post “in the queue” :-)

    But to add one more, can we at some point circle back to geo-engineering? This will soon be a necessary component of climate science, because we will be in the position of asking the question: “Can we engineer a way to reduce atmospheric CO2 levels?” This has the potential to circumvent the entire question of emissions reductions, and I consider it at least a coin flip as to whether or not such measures will eventually be necessary under any conceivable scenario.

    Thus, before it can become a business question or a social policy question, it must become a science question. Feasibility is certainly an avenue that climate science must explore, because each ‘solution’ to a perceived ‘problem’ might itself impact climate.

    I consider climate science to be the proper arena for this area of study, and I would love to see a post which explores the issue further.

  9. 159
    Bryan S says:

    Stuart, when I was studying stratigraphy about 20 years ago, it was tenaceously argued by many academic geologists that the Exxon curves were simply local curves, driven by local tectonic conditions, basin subsidence, and sedimentation rates. This argument is still ongoing, but in terms of what has gained wide acceptance in the larger geology community, the glacio-eustatic control of large, relatively rapid sea level changes in really not argued much anymore. There are virtual mountains of seismic data supporting the case for eustacy! As Ken Miller rightly pointed out, the more intense debate centers around the relative magnitude of these eustatic events, not whether the larger events are global in nature. I understand that you may have strong opinions to the contrary, but your side has not won the argument. There are people in the field of sequence stratigraphy (in and out of the petroleum industry) who have spent their careers looking exclusively at this. To geologists who get an opportunity to examine a bunch of this data, the predictive power afforded by sequence stratigraphy has stood the test of time, and yielded remarkably robust results. Virtually no geologist studying passive margins can hold a job in the petroleum industry without a strong working knowledge of sequence stratigraphy.

  10. 160
    pete best says:

    A video over at youtube entitled “the end of oil” explains anoxic seas and CO2 levels of around 4x pre industrial due to fossilised remains of plants that existed over 200 million year ago and still do today. Examining their stomata gives Co2 levels of the time. Apparantly there was a lot of volcanicity at the two times when Oil was formed by deadly anoxic seas.

  11. 161
    David B. Benson says:

    wayne davidson (139) — The continental locations at the time depth which is the main trust of this thread appear to show that Antarctica and Australia had already separated, with Antarctica headed for the south pole.

  12. 162
    Lynn Vincentnathan says:

    RE #126

    Or, “maintaining the rapid emergence from poverty of billions of people in China and India” v. “saving Himalayan glaciers from GW-induced melting and billions of lives in China and India”

  13. 163
    CobblyWorlds says:

    Dodo #116,

    Have you seen the Hadley Centre’s DePreSys (Decadal Prediction System) forecast?
    See point B of my post here: http://www.realclimate.org/index.php?p=498#comment-73163 It’s a work-in-progress, but a promising one, and may (I think) help to understand this apparent abatement.

    I’m not a scientist, just an interested amateur, but I think there probably is an abatement of warming in the Southern Ocean and Pacific. And this does manifest itself in CRU/GHCN’s global averages. However as you note Gavin is quite right to point out that it’s weather, not climate.

    If you check out GISS http://data.giss.nasa.gov/gistemp/maps/
    Set it up as follows:
    Land: GISS Analysis
    Ocean: Hadl/Reyn_v2
    Map type: Anomaly
    Mean Period: Annual(Jan-Dec)
    Time interval: 2000-2007
    Base Period: 1951-1980
    Smoothing Radius: 1200km
    Projection: Regular

    You can see lack of temperature change of the southern oceans and Pacific, and below on that page there is a graph of the lattitudinal distributions of anomaly. Try different periods, you can see that these areas are generally shown as no/little warming (even coolings) but against the current N.H. trend it may now having a greater apparent global impact on global average.

    You can also see that the abatement appears to dominate in the Southern Hemisphere (which is predominatly ocean), as implied by the Hadley Centre model (DePreSys).
    GISS http://data.giss.nasa.gov/gistemp/graphs/Fig.B.lrg.gif
    CRU http://www.cru.uea.ac.uk/cru/data/temperature/
    GHCN http://lwf.ncdc.noaa.gov/oa/climate/research/trends.html

    Raypierre,
    Thanks for the essay, sorry but I don’t know enough to say anything on topic.

    Kenneth G Miller,
    Thanks for that illuminating comment.

  14. 164
    Ray Ladbury says:

    Steve Reynolds,
    You seem to view sustaining the environment as some sort of expensive luxury. However, the agriculture to sustain those billions, the water they drink and the air they breathe is under threat. If we emphasize development without regard to the environment, we will fail. If we try to suppress development to save the environment, we will fail. It is not Either-Or. It is not a zero-sum game, and if we play it as such, we will all lose.

  15. 165
    stuart says:

    Bryan,

    I am not opposed to the global synchrony of the transgressions and regressions.

    However transgressions and regressions can be caused quite easily by internal sedimentary feedbacks alone without strong eustatic sea level changes and synchrony is often a property of weakly coupled oscillating systems.

    To say however that “glacio-eustatic control” during the Cretaceous “ … is not really argued much anymore …” is really going too far, as witnessed by the many issues raised in this very real climate discussion.

    Let’s find all this ice during the Cretaceous because it’s going to have to be a pretty persistent pheonomena, including over the entire Phanerozoic, judging by the Exxon cycles. If it is shown to be there, fine I’ll yield.

    But if it is not then we have to ask what the alternative is and I believe internal cyclicity (or autocyclicity as some refer to it) is the best bet

    [Response: This is a very informative exchange on sea level. I have encountered many geologists who found fault with the Exxon/Haack sea level reconstructions, but had been wondering about the extent to which the new isotopic data might cause a reconsideration. The interpretation of the Exxon stuff in terms of sea level is tricky, and I'm not enough of a geologist to know whose side to come down on. As somebody said, the Cretaceous is a very long time interval, and there's plenty of time for things to happen. So, I'd throw a reconsideration of the sea level reconstructions into the wild rumpus. --raypierre]

  16. 166

    Steve Reynolds posts:

    [[Barton> Despite the constant refrain to the contrary from denialists, it is possible to deal with global warming and still have billions emerge from poverty in China and India.

    I think that it is possible, only that it will take 20 to 40 years longer. I doubt that the people there will be willing to wait. That is why I favor working on long lead technology now to reduce CO2 drastically later when it will be more affordable.]]

    And if it turns out that global warming could really make the planet uninhabitable, or will kill, say, one billion people, should we still wait?

  17. 167
    Walt Bennett says:

    It is almost laughable to witness the turn this discussion has taken. In fact, it is a representation of the achilles heel of the AGW “movement” (as separated from the science). That is: “We know what’s best for you” where “you” is defined as “all those who come after us.”

    Steve raised a point which deserves more than the high-handed dismissiveness with which it has been so far met. Why would China, India or any other country abide by rules which will slow their growth, rules which did not encumber the west during its growth phase?

    Simply, and despite all of your egalitarian intentions, they will not.

    The sooner that “solution central” realizes that vast swaths of humanity see the issue through their own lenses, the sooner we can get to discussing solutions which might have a chance to actually succeed.

    [Response: Don't be so patronising. There are plenty of ways to engage India and China - not least because of the environmental degradation in their own countries. Talk about the solutions then, and stop setting up strawman 'realist' vs 'idealist' dichotomies that take no one any further - gavin]

  18. 168
    Walt Bennett says:

    Re: #167

    Gavin,

    My comment was directed not at scientists but at those, many in this thread, who have not thought through the implications of the policies being discussed. In my opinion the “talk about solutions” has been incredibly monotonic – “reduce emissions”.

    a) I give such a policy between no chance and very slim chance to actually succeed in preventing catastrophic warming;

    b) the effort to attempt to achieve that goal will raise the cost of fuel. Many people, myself included, pay more than we can afford for fuel already. Consider the implications for the many millions who are even worse off than I am.

    c) “emissions reduction” has begun to resemble a movement, which is fine if not for the first two problems. The very real risk we run is to impoverish millions while solving nothing; in other words, the worst of both worlds.

    In a separate post I requested that we do exactly what you suggest – discuss solutions. It’s a strong concern of mine that we are not doing that. I can’t find any climate change forum where alternatives to emissions reduction are discussed at all.

    I’m just one man, but I’m trying.

    [Response: Fair enough - apologies. However, this site might not be the best place for that since we are not policy people. Have you tried http://www.climatepolicy.org/ ? - gavin]

  19. 169
    Ray Ladbury says:

    Walt, I think you could do worse in discussions of human motivation than to follow George Washington’s philosophy–that people act in accord with their interests. Might I suggest that the Chinese and Indians would be sufficiently wise to adopt a view of their interests being favored by long-term sustainable growth rather than a more rapid growth spurt followed by ecological collapse? By all means, realism requires recognizing the laws of economics, but it also involves accepting the laws of physics.
    Physics tells us that there are tipping points in the climate–points where positive feedbacks kick in and change becomes irreversible. It also tells us that we don’t know exactly where those kick in. Given these uncertainties adn the potential consequences, I would contend that prudence is strongly favored.

  20. 170
    Steve Reynolds says:

    Lynn Vincentnathan> Or, “maintaining the rapid emergence from poverty of billions of people in China and India” v. “saving Himalayan glaciers from GW-induced melting and billions of lives in China and India”

    I think China and India are fully capable of building dams to control water flow from snow and glacier melt.

  21. 171
    Dodo says:

    Re 163. Yes I am familiar with the Hadley prediction. I am waiting till 2015 before I make up my mind, so I am not interested in 2009. And thanks for the links. Here’s one to boot:
    http://data.giss.nasa.gov/gistemp/graphs/Fig.C.lrg.gif

    For some reason, a trend line has not been drawn for this data. Maybe it is because it kind of looks like warming stopped in late 2001. (Sorry, Gavin, for the ad nauseam, but I was provoked.)

    [Response: No trend lines are drawn in any of the pictures on that page. But for this data the trend is 0.24 degC/dec and 0.19 degC/dec for the two indices. Both highly significant and that is still true even if you start in Jan 1998. Your point? - gavin]

  22. 172
    Steve Reynolds says:

    Barton Paul Levenson> And if it turns out that global warming could really make the planet uninhabitable, or will kill, say, one billion people, should we still wait?

    Obviously, if that is shown to be a realistic possibility without quick action, we should not wait. Rigorously examining that possibility (both by scientists in general and here at RC) is something I would like to see more of.

    As gavin says, this site might not be the best place for policy discussions, but the risk of catastrophic AGW effects is a scientific issue worthy of rational discussion.

  23. 173
    Nick Gotts says:

    Re #156 (Steve Reynolds) #167 (Walt Bennett)

    How about bringing some empirical evidence to bear on the question of the views of people in China, India and elsewhere? From
    http://www.worldpublicopinion.org/pipa/articles/btenvironmentra/427.php?lb=bte&pnt=427&nid=&id=
    you can retrieve the full results of a large-scale poll (22000 people in 21 countries) on attitudes to climate change and measures to mitigate it. I haven’t studied this in detail yet, but a strong majority in China and substantial numbers in India say they are prepared to make sacrifices (higher fuel costs and/or taxes) to mitigate it. Urban China shows among the highest figures anywhere. Of course, saying you are prepared to make sacrifices is not the same as making them, but the survey does at least call into question your certainty that India and China will never agree to reduce emissions. In any case, we won’t know unless we explore the issue in detail – in the context of international negotiations where rich countries make clear they will make their share of cuts, which need to be very substantial, and transfer efficient technology. Or we could just rely on being saved by your vapourtech for sucking greenhouse gases out of the atmosphere.

  24. 174
    Bryan S says:

    Re: #165, Stuart, I did not mean to imply that glacio-eustacy (during the Cretaceous**) was not still argued (and it should be), only that many large, fairly rapid (geologically speaking) events are correlative globally between basins. Certainly, many geologists in the petroleum industry have long suspected (maybe partially through indoctrination) that the Matthews hypothesis may have been at least partially correct, and that there was more ice during the Cretaceous than many researchers in academia have suspected. Unfortunately as I mentioned, there are very few Cretaceous rocks exposed on the Antarctic continent, so not much can be said from the available rock record. A potential serious problem with the Matthews et al. hypothesis was their methodology in deriving their conclusions. In looking at the d18O record, they made some questionable assumptions about ocean temperatures (surface and bottomwater) in the tropics. If the ocean temperatures are relatively constant, then much of the d18O variation must be from ice sheet changes, whereas if one lets the tropical temperatures change significantly, most of the proxy changes are due to ocean temperature change. In my opinion, much more can actually be said about ice sheets during the Eocene. There are *substantial* geological (real rocks) data to suggest that ice sheets extended much further back in time than the often quoted 34 million year mark, and closer to the peak of the Eocene warmth. As more people become familiar with the rock record, I predict this date will be moved further back in time.

    One of the problems in resolving these issues is that the petroleum industry has a great deal of subsurface data to look at to augment the proxy record, but cannot publish (another problem is that major companies have cut way back or demolished their research divisions, so there are really no people to synthesis all the data and write it up), and in academia, there is much less data, but more publication. It has always seemed to me that there is bound to be a niche for university researchers who wish to make proposals to the big companies to look at a bunch of this data, with the agreement that there may be some type of waiting period to publish (there is a bunch of money potentially available). Many university researchers seem somewhat intimidated by these companies, and lack contacts with the right management personel to make this connection. Maybe if some weren’t so darn politically open with their views, it might help. There is a huge gap in the political persuasion of academic vs industry scientists. Let’s not kid ourselves about that. So if the perception is that one is tainted in academia with money from Exxon, they suddenly become a scourge among fellow faculty.

  25. 175
    Jim Eager says:

    Re Walt @ 168: “a) I give such a policy between no chance and very slim chance to actually succeed in preventing catastrophic warming”

    So, then we’re all toast and just pissing into the wind?

    Walt: “b) the effort to attempt to achieve that goal will raise the cost of fuel. Many people, myself included, pay more than we can afford for fuel already.”

    Cry us a river. Increasing cost of extraction and peaking world wide production will insure continued increasing oil costs, not to mention future armed conflicts over known and potential reserves. Cheap, plentiful energy with little or no incentive to use it efficiently and without the attached costs of its harmful “external” effects is exactly what got us into our current problem. Add in those costs and it’s clear it never really was “cheap.”

    Walt: “c) “emissions reduction” has begun to resemble a movement, which is fine if not for the first two problems. The very real risk we run is to impoverish millions while solving nothing; in other words, the worst of both worlds.”

    That, plus massive disruption of the ability to feed those millions, impoverished or not, due to decreased water reserves, decreased or unreliable precipitation, increased soil salinization, inundation of low-lying fertile areas, average temperatures too high to grow rice, collapsed fisheries, and other possible effects of not reducing emissions. Your concern for the world’s impoverished masses is touching, but it rings hollow.

  26. 176
    Walt Bennett says:

    Re: #169

    Ray,

    Here’s the thing: I read your post and agree with your general stance; then I try to interpret the specifics, and find myself right where I started.

    Example: you say “people act in accord with their interests”. You then go on to surmise that the people of China and India can “adopt a view of their interests being favored by long-term sustainable growth rather than a more rapid growth spurt followed by ecological collapse”…you see those two statements as complementary, and I see tham as in conflict.

    The people of China and India have a lot in common with the people of the U.S., Canada, Australia and Europe: they want to feed their families, be gainfully employed, and so forth. Their day-to-day concerns almost certainly closely resemble ours.

    Have you noticed a growth of conscience in the country you live in, which I assume is among the wealthy nations? Are people volunteering to reduce their carbon footprint at the expense of their economic security? I didn’t think so. Now, why would the people of China and India, who can rightly feel that they desever their turn at growth, choose differently than those who have already received that benefit?

    My point is simply that they will not. And if anybody thinks they will, then it’s time to start talking numbers. What will be the impact on individual families? AGW is one huge climate experiment, with the planet as the lab. “AGW Soultions” (at this point: emissions reduction and setting aside forest) is one huge social experiment, with the population of the planet as the guinea pigs. We are a long way, in my view, from any reason to believe that this experiment, as currently constructed, will achieve the intended result.

    What this discussion lacks is realism; fatalism, if you will. What is the plan if the plan to alter the behavior of millions and millions of people fails? What is the backup? What is the failsafe?

    You write “Given these uncertainties and the potential consequences, I would contend that prudence is strongly favored.”

    I could not agree more. I consider the prudent path to avoid reliance on such a shaky “solution” (again, where are the details?) of “emissions reduction.” If we aren’t careful, this conscientious objective could devolve quickly into a vicious scam.

    Gavin,

    You wrote “However, this site might not be the best place for that since we are not policy people.” Fair enough. However, I wrote in #158 that there are important science questions to be answered before we can discuss social policy. I see no area of science better suited to this analysis than climatology. I see scientists as being in the position of providing the data necessary to inform policy. We can’t assume that this work is done; it has in fact only just begun.

    It is my sincere hope that RC will reflect this reality in its postings, and that climate science in general will start seriously asking these questions.

  27. 177
    Jim Eager says:

    Re Steve Renolds @ 170: “I think China and India are fully capable of building dams to control water flow from snow and glacier melt.”

    You’re not getting it, Steve. These dams will do what when the glaciers have melted? Have you seen what has happened to the level of Lake Mead after several years of drought and reduced snowpack in the Rockies? (Hint: there are no glaciers in the Colorado Rockies.)

  28. 178
    Jim Eager says:

    Re Walt Bennett @ 176: “What this discussion lacks is realism; fatalism, if you will. What is the plan if the plan to alter the behavior of millions and millions of people fails? What is the backup? What is the failsafe?”

    That’s just it, there is no backup, there is no failsafe, there is no control group.
    We’re living within the experiment no matter what we do, even if we do nothing.

    What, exactly, are you advocating?

  29. 179
    Daniel C. Goodwin says:

    Re: 172 “the risk of catastrophic AGW effects is a scientific issue worthy of rational discussion”

    Hear here!

    From my lay (albeit extensive) perusal of information available to me, I am struck by the wide range of informed opinions bearing specifically on how large a catastrophe AGW will turn out to be. Also, most popular science articles (i.e. in the corporate media) strike me as way off on this question of scale… as if the real worry here is whether the polar bear will go extinct.

    An almost exact analog, in terms of denial of scale, can be seen in most popular discussions of our current economic condition. I don’t seek to broaden the discussion by this comment, only to point out that we are apparently very talented at kidding ourselves, in all kinds of ways. This is the principle problem behind the problem of AGW, in my most humble opinion.

  30. 180
    Walt Bennett says:

    Re: #175

    Jim,

    You missed my point completely. Please re-read all of my posts on this issue, and it will become clearer.

    Your stance embodies everything I am concerned about.

  31. 181
    CobblyWorlds says:

    #171 Dodo,

    I can’t see where you were “provoked” in my #163. ;)

    Re the graph you linked to, as it says on the owning page:
    http://data.giss.nasa.gov/gistemp/graphs/
    “Line plot of monthly mean global surface tmperature anomaly.”sic.
    Given the noise of intra-annual temperature excursions, I would suggest that’s a good reason not to give a trend line or apply a multi-annual smoothing. For long term trends, surely individual months (whatever that would mean given the opposing hemispheric seasons) or annual average would be a better place to use trend lines or smoothing (e.g. 5 year averages). Not a bad plot for studying something like ENSO impact on Global Average Temperature (GAT) though.

    What both the hemispheric averages and the DePreSys data suggests to me is that something else (non-AGW) is afoot in the apparent recent abatement of warming. Given that anthropogenic climate impacts are not the only climatic factor (although they are becoming the predominant factor decadally), this does not surprise me. I posted that link because you seemed to be unaware of this, mea culpa.

    2015 – you’ll be seeing how GAT is, I’ll be seeing if the Arctic is ice free in September…

    Bye bye
    Cobbly.

  32. 182
    Mark A. York says:

    I’ve been asked if there is a debunking to this political hit piece by CBC? Of course everything here debunks the assertions that we are just naturaly coming out of the LIA and Mike’s graph is screwed up. Sigh. They use the ad nauseam fallacy effectivel for their audience because this is what politics does. Legates, Chrisy et al.

    Global Warming – Doomsday Called Off (1/5)
    http://www.youtube.com/watch?v=fr5O1HsTVgA&mode=related&search=

  33. 183

    RE #168, since reducing emissions (in the U.S. especially) can be done in ways that save money without lowering living standards, at least to a 75% reduction or more, this could only help the economy, not hurt it. My husband and I were able to do so. It just takes a bit of effort.

    Hunter Lovins ( http://www.rmi.org ) has even said the poor cannot afford to be inefficient. But they are. I remember reading out one poor woman in a 1 BR apartment in Chicago who had a gas bill of $400 one month (while ours in a 3-BR house in the Chicago suburbs was $100 that month. Our friend in a nearby Chicago burb had a gas bill of less than $20 dollars that same month in his passive solar home.

    Lovins said, “The national energy policy comes down to the cracks around your windows.” Also check out http://www.natcap.org , which claims we can reduce 90% cost-effectively, by “tunneling through,” among other measures.

    Ben Franklin is the one to follow here — “A penny saved is a penny earned.”

    Or, it’s not very wise to take your money and burn it out on your front lawn like so many fall leaves. At least think of all those GHGs that would emit.

    In economic terms we are operating well within “the production possibilities frontier.” (We are highly inefficient and profligate.)

  34. 184

    RE #170, it’s not just the floods in their more immediate future (and if we can’t keep water out of N Orleans or areas here in the U.S. that get flooded, why should we have so much confidence India and China will be able to do so).

    It’s the demise of the glacial cycle, where fresh snow pack in winter builds up the glacier, which then slowly releases meltwater during the dry summers that irrigates their crops. When the glaciers are all melted in a GW world, and there’s no snowpack build up, then there will be floods in the winter and no water in the summers — for irrigation or drinking. We are looking at potentially massive famine in India and China.

    And that is only one negative aspect of GW and other pollution related to GHG emisions. Add in heat deaths and disease spread, and crops withering in the heat, and many other such effects, and it may amount to a very big disaster.

    The potential for avoiding this in cost-effective ways is very good. For instance, villages can collect livestock and human manure, turn it into biogas for generating electricity and cooking. The remainder substance ends up being an even better fertilizer than applying manure directly to crops. There are a few model villages doing this right now. Sure beats burning wood, filthy kerosene, or cow paddies, which are the major current cooking fuels in India. And why shouldn’t Indian villagers have electricity so they can have a tube light so their kids can study and go to college, like our kids? Or a fan to blow off the mosquitos at night. This is a way villages can have these.

  35. 185
    B Buckner says:

    Jim #177

    I don’t understand your point. The Hoover dam essentially functioned as a glacier would, storing water and getting the southwest through several years of drought without a supply disruption.

  36. 186
    Walt Bennett says:

    Re: #178

    Jim,

    You have arrived at the pertinent question? Far be it from me, a simple layman in these matters, to suggest what ought to be done.

    However, I have two broad proposals:

    1. Realistically assess the feasibility of “emissions reduction” as a viable standalone solution to rising CO2 levels. What, specifically, must happen for this to work? We need real numbers and we need them very soon.

    2. Open climate science to all questions with regard to atmospheric composition. Man has ALREADY altered that composition; the solution to AGW requires that we continue to do so. Method 1: let nature take over, may not suit man. The planet does not have a preference for one state over another; conditions determine that. I highly suspect that the planet will happily morph into a warmer state, and the law of inertia says that it will require great force to alter that state once it has been achieved. In other words, letting nature take over may produce a planet we really aren’t well adapted to. And I mean this: even if we achieve our emissions reduction goals, the planet may still shift to a warmer state. So, we need to be scientifically open to engineered alterations of atmospheric composition. We need to dedicate monetary and human resources to this branch of the climate science tree.

    And we need to hurry up.

  37. 187
    Hank Roberts says:

    > Lake Mead
    http://www.arachnoid.com/NaturalResources/image.php?mead

    “there seems not to be a convenient monthly water level database for Lake Powell, as there is for Lake Mead.”

    Lake Powell is upstream from Lake Mead: http://earthobservatory.nasa.gov/Newsroom/NewImages/Images/powell_ast_2000142.jpg

  38. 188
    Ray Ladbury says:

    Walt,
    OK, so how is opting for policies that ensure that your grandchildren have gainful employment and food on the table idealistic? If anything, the Chinese and Indians have shown greater propensity for this than have Americans. And yes, even in the US, I am seeing more and more people fed up with government inaction and taking actions to reduce their consumption. It is not universal, nor is it sufficient, but it is a start.
    Ever read Albert Camus’ The Plague? Excellent book–and it is the most mature statement of Camus’ philosophy. The gist of it is that initially, people react selfishly, but when it becomes clear that the way to survival is to cooperate, they do so, even if the cooperation involves increased hardship or even risk to the the individual.
    Walt, there are few who would accuse me of idealism. However, I do know that the only strategy we have that will work right now is to decrease emissions. Geoengineering solutions that involve aerosols, etc. involve unanticipated effects that we don’t know how to model at present. Carbon capture and storage is unproved on a large scale. I also know that we are not far away from various tipping points–loss of arctic sea ice, increased natural sources of CO2 and CH4, depletion of the oceans ability to absorb CO2, ocean acidification. We want to stay away from these.

    I think it would be very interesting if RC took a look at worst-case outcomes of climate change in terms of what models and paleoclimate suggest. I think there is quite a disconnect between what the impressions of different posters.

  39. 189
    Jim Eager says:

    Re B Buckner @185: “I don’t understand your point. The Hoover dam essentially functioned as a glacier would, storing water and getting the southwest through several years of drought without a supply disruption.”

    Look at the marked falling level of Lake Mead and tell us that with a straight face. And then tell it to those dependent on over-allocated Colorado River water for municipal drinking and agricultural use.

  40. 190
    Walt Bennett says:

    Open Question:

    Do you agree or disagree with the following:

    “Man is now responsible for managing the climate of the planet.”

  41. 191

    #161, Thanks David. Would be good to have an “official” map of the said periods of glaciation.

  42. 192
    SecularAnimist says:

    Walt Bennett asked: “Can we engineer a way to reduce atmospheric CO2 levels?”

    Yes, we can draw down atmospheric CO2 levels using natural processes, through (1) large-scale reforestation and (2) organic agriculture techniques that return carbon to the soil.

    But there is no hope of “reducing” atmospheric CO2 levels while we continue increasing them with accelerating growth in emissions.

    Walt Bennett wrote: “Steve [Reynolds] raised a point which deserves more than the high-handed dismissiveness with which it has been so far met.”

    With all due respect, Steve Reynolds raised a scripted talking point — the assertion that taking necessary steps to reduce CO2 emissions will condemn millions of people in the developing world to poverty — that is entirely deserving of “high-handed dismissiveness” because it is demonstrably bogus, and has repeatedly been aired-out and shown to be without merit in discussion threads on this very site.

    Every national and international agency that deals with overcoming poverty in the third world has said that the effects of global warming are already hindering and setting back their efforts, and that unmitigated global warming will have particularly catastrophic effects on the world’s poor, and completely overwhelm and destroy any hopes of reducing poverty and human suffering, such as those embodied in the UN Millennium Development Goals. On the other hand, a rapid conversion from fossil fuel energy to clean, renewable, distributed, democratically-owned and controlled energy generation from wind, solar and sustainably-produced biofuels — a “second industrial revolution” could stimulate economic growth worldwide, both in the developing world and the industrialized west.

    Mitigating global warming by migrating from fossil fuel energy to clean renewable energy, by large-scale reforestation projects, and by moving to sustainable organic agriculture and a plant-based diet, is not an obstacle to reducing the poverty of the developing world — it is in fact the only way to lift hundreds of millions of people out of poverty and into sustainable economic well-being.

    Walt Bennett wrote: “Are people volunteering to reduce their carbon footprint at the expense of their economic security? I didn’t think so.”

    In fact many people, and indeed corporations, are volunteering to reduce their carbon footprints by implementing efficiency and new energy technologies and thereby improving their economic security. The dependence of the US economy on fossil fuels is a source of economic insecurity, and reducing that reliance through efficiencey and clean renewable energy technologies would enhance the country’s economic security. Your implied assertion that reducing one’s CO2 emissions necessarily requires reducing one’s economic security is baseless.

    Walt Bennet asked: “Now, why would the people of China and India, who can rightly feel that they deserve their turn at growth, choose differently than those who have already received that benefit?”

    First of all, because they will benefit by choosing differently; second, because there are plenty of available options for choosing differently; and third, because the option to follow the same growth path that this industrialized West did — one based on ample supplies of cheap fossil fuels, and an atmosphere, hydrosphere and biosphere with the capacity to absorb gigatons of excess carbon and other pollution before all hell breaks loose — simply doesn’t exist. If China and India attempt to follow that path, it will lead to the collapse of their societies and the deaths of hundreds of millions of people in those countries from famine, disease, pestilence and war.

  43. 193
    Walt Bennett says:

    Re: #188

    Ray,

    You and I do not fundamentally disagree on the need to avert catastrophic warming. If anything, I believe that current Climate Science orthodoxy is much too conservative. Whether or not global temperatures skyrocket in the next decade (as I believe they will), we are seeing more and more signs that the climate is shifting in permanent ways. The signs could be wrong, or they could be the early warning that we will one day come to recognize as the start of the shift to a warmer planet.

    Of course I am in favor of a zero carbon emissions planet. I am in favor of clean energy. I am in favor of social policies which encourage this shift.

    I am stuck with this concern: what if it is later than we think? And, what if we completely miss our targets for emissions reduction? And, what if the reduction in soot has a sudden impact on warming? And, what if it turns out to be incredibly difficult to reverse some of the processes which are underway?

    What I am struggling to communicate is: we really need a lot more science on the above questions, and on all possible alternatives to avoid the worst consequences. And we simply must do all of this without placing an extra economic burden on those who already cannot afford basic energy.

    To whoever it was who scoffed at my concern over energy costs, based on the idea that scarcity will raise the price anyway, my concern is that the Big Plan is to increase that cost even further. This will create a much broader and deeper class of impoverished people, whose only real problem is their inability to afford or access basic energy at a decent cost.

    I don’t know how else to say it: we run the risk of ruining millions of lives without actually solving the problem. We really need to expand our ability to question the strategies we have been asked to accept. We need numbers and we need them soon.

    I assume we’re all on the same side here. We have one chance to get this right.

  44. 194

    #182 Mark, Don’t know if it was a CBC produced documentary per se, judging by the narrator’s accent its either British or Australian… Segment 1/5 shows that it was much warmer for many of the past 10,000 years. How interesting, perhaps Bowhead whales of the Eastern Arctic didn’t like the Bowheads from the Western Arctic, so they kept to themselves in their own migratory courses dictated by a time when it was colder, despite all that wide open water to enjoy… As with Antarctic dinosaurs, one strong rebuttal may be found in biology. But then again past glacial rebound of the last 10,000 years have made it so that you can find
    an ancient Bowhead skull or complete skeleton many hundreds of meters above sea level, many can be found even today, rebound means that it was colder then and much warmer now, but I guess that the producer wasn’t interested in these facts.

  45. 195
    SecularAnimist says:

    Walt Bennett wrote: “Do you agree or disagree with the following: ‘Man is now responsible for managing the climate of the planet.’”

    The only thing we are responsible for “managing” is ourselves. There’s nothing wrong with “the climate”, and “the climate” is perfectly capable of “managing” itself. What’s wrong is us, the pollution that we are creating, and the impossible demands we are placing on the Earth’s biosphere, atmosphere and oceans. That’s what needs to be “managed”.

    Talking about “managing the climate” while the entire Earth’s biosphere is rapidly sickening from the pollution that we have produced, and our degradation of ecosystems, sounds to me like an alcoholic diagnosed with cirrhosis who decides that the solution is not to stop drinking, but to “manage” his liver, since he is obviously much smarter than some dumb old liver, and under his “management” the liver will be able to process all of the alcohol he cares to drink.

  46. 196
    B Buckner says:

    #189 Jim
    The only function a glacier serves in water supply is to provide a buffer during drought years, otherwise you are dependent on that years rainfall or snow melt. Of course lake levels have fallen dramatically in Lake Mead, there has been seven years of drought and withdrawals continue at regular rates. But because of the dam, there has been no supply disruption.

  47. 197
    Hank Roberts says:

    Walt wrote:

    > “Man is now responsible for managing the climate of the planet.”

    I would say “We’re now changing the climate, and managing that change would be responsible.”

    Or as Stewart Brand wrote, on your grandparents’ Whole Earth Catalog:
    “We are as gods and might as well get good at it.”

    We are acting like gods — petty, venal, shortsighted, selfish. We ought to improve on it.

  48. 198
    Tim McDermott says:

    Walt Bennett:

    So you agree or disagree with the following:

    “Man is now capable of managing the climate of the planet.”

    I suspect your answer is yes. My answer is no. Hippocrates admonition to physicians comes to mind, “First, do no harm.” I doubt that any of our host climatologists would feel inclined to certify that any particular geoengineering scheme would do no harm, and if I’m wrong I hope they correct me.

    The history of engineering is a collection of disasters; exploding boilers, burning buildings, and collapsing bridges. Engineering is very good at perfecting things. It has a much spottier record at being right the (very) first time.

    I would much rather that we put our energy into engineering solutions that are in reach, and that show immediate personal savings and global relief: better solar, better wind, better conservation. They may not be perfect. They may not be enough (but then they may). But they are steps in the right direction. The geoengineering grand slam strikes me as just another excuse to not do anything while waiting for some deus-ex-machina salvation.

  49. 199
    Ray Ladbury says:

    Walt Bennett said:

    “Open Question:

    Do you agree or disagree with the following:

    “Man is now responsible for managing the climate of the planet.””

    Your question is irrelevant. We are already mismanaging the climate of the planet.

  50. 200
    David B. Benson says:

    wayne davidson (191) — I provided a link to a map for the Cretaceous much earlier on this thread.


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