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Tuesday, September 21, 2010

Scientists Matthew Huber, Carl Wunsch, Daniel Schrag, Burton Richter, David Keith & Martin Hoffert react to Nobelist Laughlin's climate thoughts

Scientists React to Nobelist Laughlin's Climate Thoughts

Matthew Huber, Purdue University:
It’s pretty clear that his Nobel is not in the Earth Sciences. The crux of his argument is that “Nobody knows why these dramatic climate changes occurred in the ancient past. Ideas that commonly surface include perturbations to the earth’s orbit by other planets, disruptions of ocean currents, the rise and fall of greenhouse gases, heat reflection by snow, continental drift, comet impacts, Genesis floods, volcanoes, and slow changes in the irradiance of the sun. No scientifically solid support has been found for any of these suggestions. ”
In other words he apparently thinks we live in a world of mysterious forces which are utterly incomprehensible and climate has responded like a voodoo doll to invisible hands through time. Perhaps they are incomprehensible to him. He needs to take some courses in paleoclimate — I suggest he start at the undergraduate level. I hear there might be something appropriate being taught on his campus. His know-nothing approach hearkens back to the pre-scientific era of the flat earth, vapors and phlogiston.
Many of the factors he lists are indeed well known to be responsible for the major climate changes in Earth’s history. He is quite incorrect to say that “no solid support has been found for these suggestions”. There are thousands of studies establishing exactly those processes as being important. It is quite certain that orbital influence, greenhouse gas concentrations, and circulation changes, together with internal Earth System feedbacks, have caused climate change. Greenhouse gas concentrations play a large, and perhaps even dominant role in these changes.
High concentrations caused the warmth of the Cretaceous and Eocene worlds, and subsequent decreases (in combination with the other listed factors) initiated the glaciation of Antarctica. At lower concentrations, and in the presence of changes in continental geometry and ocean circulation, glacial-interglacial cycles became possible. This is very well understood within the framework of people like Didier Paillard and David Archer. The same lessons apply for the future — raise greenhouse gases and the climate will warm substantially. There is no great mystery here, other than perhaps why a Nobel prize winner is either ignorant of the major results of the field of paleoclimatology over the past two decades or simply chooses to ignore the science for the sake of some sound bytes.
Our understanding of the climate system is still rudimentary but ultimately we know what the big knobs are that turn up the heat and those are the same knobs we are cranking on right now. We know this absolutely and have known at least since Arrhenius and he got the Nobel (in 1903)!
Carl Wunsch, Massachusetts Institute of Technology:
It is clear that much of the physics community believes it knows much more about climate change than do earth scientists (recall the  bio. of Freeman Dyson in the Sunday Times Magazine). Much of the skepticism by people like Dyson arises from the use of extremely complicated numerical models interpreted as being predictions. Many physicists look at those models and say something like “we know about numerical simulation and you can’t possibly believe those results.” They then infer that the whole subject is garbage. That Arrhenius and others worked out the basic physics 100+ years ago, almost on the back of an envelope, has been completely lost to sight. (And there is no doubt that a lot of rubbish is propagated as climate science.)
Laughlin’s case is different, and suggests willful ignorance. The physics argument seems simply that (1) past climates have been very different from today (true); (2) the changes are large compared to what we see from global warming, or expect to see, anytime soon (true). Ergo (3), there’s nothing to be done. (Physics arrogance is real, as are non sequiturs.)
I’m reminded of the old joke about the man falling off the Empire State Building who as he passes the 30th floor says “so far so good.” Civilization arose and thrives in a rather narrow climate range. And the earth never before had 6+billion people. I wonder if Laughlin has views about proliferation of nuclear weapons? After all, the amount of energy releasable is a tiny fraction of what we get from the sun — so why worry?
 Daniel Schrag, Harvard:
Yes, there can be natural climate changes over thousands or millions of years that are large compared to what we are experiencing now. But in fact, our actions have risen well above the level of any natural variations because of their pace. Without our use of fossil fuels, we should be descending into another glacial maximum – albeit slowly, over tens of thousands of years (the pace of natural global climate change in the Pleistocene). And instead our actions have interfered with this natural cycle and we are in the process of completely deglaciating the planet.
Indeed, if one takes David Archer’s calculations seriously (and we should), roughly 20 percent of the CO2 that comes from burning fossil fuel will be there tens of thousands of years from now, and so if we end up well above 400 parts per million for tens of thousands of years, there is much less doubt that Greenland will melt in its entirety and that Antarctica may well deglaciate as well. The idea that the climate system is so powerful that it is beyond human influence is simply incorrect….
Burton Richter, Stanford University:
Laughlin’s point is obviously true, but is not really relevant in the short (centuries) term. In the 500 million years since oxygen became plentiful in the atmosphere it has been hotter and colder (according to some ice once covered the entire earth). The ancestors of our species seem to have existed for about 4 million years and went through lots of extreme climate changes. There were few of us and we could and did move. The time for a significant temperature change was measured in tens-of-thousands of years and movement was not hard. Now there are 7 billion of us and we will be 9 billion by mid-century. It pays to try to slow the pace of change until the population declines (each forecast of the U.N. population group for 2100 has been smaller) and energy technology give us a chance to slow change while meeting the aspirations of the world’s people. Bob Laughlin may be right in the long term, but it is our responsibility to try to keep things stable during our lifetimes before passing the job on to future generation who may or may not succeed.
David Keith, University of Calgary:
A few comments on physicists as climate skeptics.
I had an interesting experience talking to Dyson and Will Happer at a meeting last year. I was thrilled to talk with Dyson. I have loved his writing since my first mentor in physics handed me Dyson’s  Disturbing The Universealong with the Feynman lectures when I started working in a big laser lab during high school. Later I enjoyed his papers when I got to field theory.
Dyson’s comments on climate were disappointingly shallow. I said, “Are you concerned about the exaggeration of climate impacts or do you have serious concerns about the science?”
“Both,” he replied. But when I pressed him on the science the only thing he said was that CO2 radiative forcing was logarithmic and complained that nobody knows this or talks about it. It was disappointing to hear such a shallow commentary from such a great man. Everyone who needs to knows that CO2 forcing is (roughly) logarithmic. This science is more than half a century old; it is in any textbook; the I.P.C.C. even as an “official” log forcing function that is widely used in simple policy analysis models. This science of building good high-resolution radiative transfer codes was nailed by Gilbert Plass and others at the air force geophysics lab in the 1950’s.
If one is going to attack the climate science this is a very odd place to start.
I also talked to Will Happer who testified in Congress, slamming climate science is nonsense. The conversation was much the same. When asked for some specific critique of the science his only answer concerned the saturation of the CO2 spectral lines, yet he seemed to have little or no familiarity with the content of modern (i.e., the last 30+ years) radiative transfer models which treat such line broadening with high accuracy; and, unlike some other components of climate models, this stuff can be well validated from both first principles and experiment (N.B., I built a high accuracy radiometer that flies on the U-2/ER-2 that does this). This critique is closely tied with Dyson’s comment about logarithmic response to CO2. It is likewise trivially without foundation. From Happer, a very smart and creative experimentalist in the same atomic and molecular physics world that I came from, this is embarrassing and disappointing.
My hunch is that Dyson, Happer and others like them are reacting to the apocalyptic overstatements by some in the climate advocacy world such as Gore.
Folks like Dyson who have thought a lot about nuclear weapons have a much higher threshold for things they call “catastrophic.” If a big nuclear war is you benchmark for catastrophe then climate change looks tame. Moreover, Dyson seems unconcerned about wholesale human manipulation of the natural world, and is convinced the economic impacts of climate change will be slight. These are statements about values and economics. I think they are perfectly reasonable views, even though I don’t wholly share them. If Dyson kept his critiques to this ground I would have no trouble with them, indeed they might sharpen the debate since there is lots of facile exaggeration in the enviro camp.
However, I think it is a misuse of their reputations as physicists to have folks like Dyson, Happer and Laughlin and publicly dismiss the underlying science without offering a technically substantive critique.
If their concern is overhype about the risk of climate change they should critique that overhype directly.
 Martin Hoffert, New York University:
No. No. No to geologists and other “pundits” decoupling the issues of human energy systems from climate change.
Without the possibility of catastrophic climate change radically changing Earth’s environment in decades to a hundred years or so, creating a new global energy system would be a problem for the 22nd Century plausibly tackled in a leisurely way without failure posing an existential threat.
Plenty of coal to run high tech civilization at least another hundred years even with substantial economic growth by burning it in conventional coal-fired electric plants and making liquid hydrocarbon automotive fuels from it. It is planet-transforming climate change — from coal-burning plants now on track to be built by China, India and the U.S. that, de facto, will become the energy infrastructure of the middle and late 21st century — that makes a push to urgently transform of our energy system away from fossil fuels the challenge of the century.
Revelle and Seuss’s “Grand Geophysical Experiment” — they had the luxury in the late ’50s to define it in that geologically detached way — will dump thousands of gigatonnes of carbon from gas, oil and coal into the atmosphere as CO2 as they are burned for energy a million times faster than these fossil fuels were made by nature.
This pulse, and its impact on climate, is precisely the problem. It is what drives the need to research, develop, demonstrate and deploy carbon-neutral and sustainable energy sources to power civilization in the coming decades to the end of the century. Of course, the impacts of human climate change will persist over deep geological time, just as for example, the Paleocene-Eocene Thermal Maximum warming did. But the urgency for energy policy is very near term. Surely geologists should be able to understand how different time scales affect the planetary environment. The human fossil fuel CO2 emissions spike is more like an asteroid impact than the slow degassing of CO2 from metamorphic decarbonization of carbonate rocks at subduction zones by the slow grinding away of plate tectonics.
Those arguing that the fossil fuel greenhouse is unstoppable because of hard-wired human short-term greed, scientific illiteracy and failure of technological imagination may have a point, But think about this: Building seawalls, massively air conditioning new habitats inland and dealing with a flood of environmental refugees as the planet warms with take a huge chunk of additional energy in itself. If that energy comes from burning relatively abundant coal it will only worsen climate change and acidification of the oceans. All the more reason to press for a transformed global energy system. We may not succeed for technical or human behavioral reasons, but as scientists and engineers we ought to at least go down fighting.
If we fail, I can imagine a thousand years from now a small fragment of humankind barely surviving the new planetary climate huddled round a fire in some remote northern latitude observing the night sky, subsisting perhaps as hunter-gatherers on a vastly different and biologically depleted planet listening to a tale vaguely recalled in ancestral memory by the local shaman.
He might yell of humans once walking upon that Moon in the sky. But even little children would know that only gods, not men, not puny men so self-destructively maladapted to technology, could do that.
The geologists are right that Earth will abide. The question is: Will we?

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