Temperatures rising

Everywhere you look, and now in PAW, contrarian scientists get easy and respectful media coverage. Mark Bernstein ’83 gave Professors Happer and Austin a bully pulpit, and seems to have been taken in by them (feature, March 17).

The article starts by subtly framing the whole issue in pejorative terms, calling the effort to acquaint the general public with the climate-change crisis a secular religion. Later it calls Happer’s rejection of a professional consensus ”an act of apostasy.” Surely the two responded to widespread criticism, likening it to the Nazi persecution of Jews, in predictably emotional and ideological ways. A better journalist should have been cued by their outrageous statements that they, quite understandably, react to such general rejection of their views by feelings of hurt and persecution that verge on the paranoid. 

No, I am not calling them psychotic, nor am I presuming to diagnose at a distance.  Normal people do react in potentially pathological ways under stress. My main aim is to give the case they make a dispassionate hearing despite its emotional wording.

The first statement about data puts on equal footing the undeniable fact that glaciers are shrinking ”at the edges” and the hypothesis that “they may be getting thicker at the middle.” That speculation contrasts with many observations about the formation and then disappearance of surface lakes on the interior surface of the Greenland ice cap as they drain into fissures and lubricate the glaciers’ movement, an unprecedented and widely reported fact. Bernstein follows with a later statement that “glaciers, at least in some areas of the world, are shrinking”; would a lay reader think that “at least some” is actually the vast majority? 

Second, “20th- and 21st-century climate changes are neither exceptional nor persistent.” True, by an irrelevant reading of the facts. Some changes are indeed similar to others in the reconstructed record of the past million years, both periods of warming and of cooling. No climatologist denies that elementary observation. Part of the problem is that these two men, who may be distinguished in their own fields, write and speak as if colleagues whose work is much more directly relevant than theirs are ignorant of or don’t give adequate consideration to phenomena that are old hat to the real experts. Sure, “ocean cycles and solar variability also might account for rising temperature” – they explicitly are included in most climatological models, so why talk about them as if they had been overlooked?

Third, Happer’s claim that “climate-change advocates ignore the fact that there have been several periods, including the past 10 years, in which there has been no warming.”  No doubt it is true that many lay journalists have not noticed that the long, slow, upward trend of warming since the Industrial Revolution has had periods of temporary fluctuation, but deniers generally lack the perspective to see the long-term trend in a highly variable record. One would think that two distinguished Princeton professors would keep up with a topic in which they are interested by a regular reading of the AAAP’s journal Science, but it is hard to see how they could make many of their assertions if they did so. Even by last July, the exaggeratedly emphasized statement in the letter to Congress by the “skeptics” concerning evidence “to prove global warming,” that “THERE IS NO SUCH EVIDENCE; IT DOESN’T EXIST” could not have been made by a conscientious reader of just this one journal.

Fourth error: Dyson and Happer are simply wrong that rising levels of CO2 will benefit mankind “by increasing crop yields and making more parts of the globe available for cultivation.”  Well-designed research, recently published in peer-reviewed journals, shows that the beneficial effects of added CO2 are limited and reverse quickly just above current levels, while agronomists and climatologists alike are alarmed by the great increases in desertification, erosion, salination from over-irrigation, and other trends rapidly making far fewer “parts of the globe available for cultivation” while growth of populations and incomes create greatly increased demand for food.

Then there is the big fuss in the popular press about “Climategate” and “Glaciergate.” It does Professors Austin and Hopper little credit as skeptics that they credulously swallowed the charges that the stolen East Anglia e-mails were a tremendous exposure of flimsiness in the evidential basis of the climate-change crisis, amounting to the worst scientific fraud in memory! Their letter to the members of the American Physics Society showed them to have little better ability to counsel the public about global warming than most Tea Partiers, and should be an intense embarrassment following the careful examination of the facts and circumstances by impartial colleagues, which have shown both “Gates” to have been trivial errors.

Mark Bernstein ’83’s article (feature, March 17), and indeed much of what Professor Happer says, is really beside the point. Carbon dioxide is heavily absorbent between 10 and 20 microns wavelength. This is the range in which the ice crystals that form the fluffy white tops of clouds and the snow and ice of glaciers and polar caps radiate at night to lose the heat energy they received during the day. Changing this small but key piece of the planet’s heat balance clearly is going to do something. If a great deal of melt water enters the polar oceans, the driving force of the north-south currents will diminish, and it is possible that this diminution will actually make some parts of the planet colder. The minor change in the infrared opacity of the atmosphere will have little direct effect on the equatorial and temperate regions where most people live, other than producing changes in cloud formation and coverage, so the term “global warming” is just an immense red herring. Changes in weather patterns and polar ice caps, however, are quite another matter.

I am appalled at the lack of depth in the position taken by Professors Austin and Happer in the debate on climate change (feature, March 17). Surely, as physicists they must be aware of and should have given consideration to the well-established principles that (1) a complex non-linear system can produce unexpected short-run oscillations in the variables that define its state-space, especially when such systems enter state-space domains characterized by criticality where systems’ stability and predictability can deteriorate into chaos; and (2) that major meteorological systems are prime examples of such complex non-linearity – as demonstrated mathematically by Edward Lorenz, the “father of chaos theory” and meteorologist – and exemplified historically by the 1,000-year deep freeze of the Younger Dryas, which occurred during the period of great global warming following the end of the last ice age.

Principle (1) entails that yearlong and decadelong examples of ambient cooling or glacial thickening have little if any bearing on the overall longer-term trends and, in fact, the oscillations can serve as a warning that our global meteorological system may well have entered the potentially unstable domain of criticality. If the system under consideration is defined over a geometric space, this principle also means that one can expect the distribution of values for any system variable can at any one time vary widely geographically and individual measurements can be contradictory. The validity of virtually every empirical example supposedly supporting the climate-change skeptics is rendered questionable by the above considerations. It also means that, in principle, within the domain of criticality, no mathematical model can ever predict accurately future (or relevant past) conditions. Paraphrasing Lorenz’s conclusion, the flutter of a butterfly’s wings in California can result in a hurricane in the Caribbean.

The crucial issue in considering the threat facing mankind today from climate change is the possibility that our global meteorological system is approaching or is entering the domain of criticality (similar to the period that initiated the Younger Dryas). Evidence supporting such a hypothesis would be an increase in the incidence of extreme (“all-time record”) events of any kind around the globe – whether or not they seem to fit or refute the apparent long-term trends.   

And it should be noted that whether or not human activity has “caused” or “is causing” the long-term trend supporting “global warming” is irrelevant – the hypothesis is dubious at best if taken seriously. What is crucial is whether human activity is contributing in any way to the system variables – and hence to its increasing instability – in a way analogous to the butterfly flapping its wings. That is, our contribution does not have to be primary or major – if our activity in any way is pushing the system into the domain of criticality, we should examine how best to reduce or modify our contribution.

As for the pathetic argument that humanity thrived when temperatures were warmer and hence we can expect to benefit from global warming, the homo sapiens population that supposedly “thrived” numbered less than a million over the surface of the Earth and as hunter-gatherers were socioeconomically free to move quickly to more favorable geographical locations (which they did). It also might be noted that by the end of the Younger Dryas – which created extreme conditions – according to recent estimations, the total population of homo sapiens fell to less than 100,000. But more to the point, the current socioeconomic constraints on the current world population of 7 billion human beings would make impossible any geographical adaptations to cope with the most likely consequences. Rather, the most likely outcome of continued global warming would be a demographic apocalypse around the world – and with it, severe economic collapse – as the most densely populated areas are very close to major ocean systems – or depend upon predictable water flows from what would become greatly diminished or no longer extant glacial systems.

One more crucial observation is that rising sea levels are almost certainly not the most immediate threat implied by the current dynamics within the world meteorological system. Much more devastating would be more frequent and violent weather events, severe multiyear shifts in rainfall patterns producing destructive floods or droughts, collapse of ecosystems upon which human populations depend, and the interruption of the flow of major ocean currents due to buildup of fresh water on the surface of the oceans. Any or all of the above could occur without any major shift in the mean values of any “key variable” such as CO2 emissions.

I strongly suggest that Professors Happer and Austin stop trying to win specious arguments and instead do some revision in the fundamentals of complex system theory – after which they then could make much better use of their energies by considering how our institutions can best organize to meet the possible consequences of the looming instability in the world meteorological system.

As I read the article on the role of professors Happer and Austin as climate-change skeptics, two thoughts came to mind. First, it pleases me that the Princeton physics department has been supportive in spite of their dissenting scientific positions. Second, although they are correct that the Earth has survived large temperature increases in the past, human civilization has not been similarly tested. Optimistically, human­kind would respond cooperatively to inundation of coastal population centers and displacement of water supplies and agricultural zones by sharing resources and land. However, I fear history tells us the more likely outcome is war, famine, and social upheaval.

In his article on global-warming skeptics (feature, March 17), Mark Bernstein ’83 presents a nicely balanced discussion of some of the controversies surrounding this issue. However, a more nuanced discussion of the “dire consequences” of global warming might have been helpful. It is clear that increasing levels of carbon dioxide eventually will have a catastrophic effect on equatorial regions, in particular on the African continent. But such an increase in greenhouse gases could also prove to be a boon to subarctic regions such as Canada, Siberia, and Patagonia. When the Arizona desert expands into Kansas, and cornfields flourish along Hudson’s Bay, people will move. So it appears quite possible that global warming will result in a vast redistribution of human populations over the surface of the Earth during the 22nd century.

We are dismayed by PAW’s article covering two Princeton physics professors’ opinions concerning climate change. Professors William Happer and Robert Austin reportedly criticize climate scientists for “group think” and claim that “only a few have looked at the raw data.”  

This is false. Climate scientists have been testing hypotheses concerning the causes of climate change for decades and subjecting these findings to review and further testing. The 4th Assessment Report (AR4) of the Intergovernmental Panel on Climate Change (IPCC), for example, cites numerous published scientific studies that examine “raw data.” Professors Happer and Austin provide neither data, nor analyses, nor references to peer-reviewed literature to support their contentions.  

Moreover, many of the factual claims reported in this article are demonstrably incorrect. For example, the assertion that human emissions are not causing atmospheric carbon-dioxide concentrations to rise contradicts numerous studies (enumerated in AR4 chapter 1.3). The statement that “there is no evidence that the rate (of contemporary sea-level rise) is increasing” similarly contradicts abundant research (summarized in AR4 chapter 5.5, plus more recent references). And it is blatantly wrong to claim that climate scientists have “ignored the fact that there are several periods ... where no warming has occurred.” The ability (or inability) of climate models to reproduce successfully the 20th-century observational record is one of the primary measures used to evaluate our understanding of Earth’s climate (e.g., AR4 chapter 3.2, 9.3, 9.4).

It is unfortunate that both the tone and content of this article contributed to the very sort of polarized, groundless advocacy that Professor Austin claims to wish to avoid.

Dr. William Happer *64’s comments have the same character as the rhetoric he attributes to anthropogenic climate-change “believers.” He does not refute the climate-change evidence that he is most qualified to refute, concerning the radiative properties of gases, but focuses on other issues. This gives the impression of arguing from a weak position and justifying a preconceived conclusion, which does not merit a response, but his dismissal of the precautionary principle does. His assertion that limiting our carbon emissions would impair America’s economic competitiveness is only plausible in the short term and only if we take unilateral action. It can’t be unilateral because some countries already are leading us. These countries surely would like us to yield the next low- and no-carbon energy technologies to them. Much of the rest of the world is waiting for us to lead.

There’s no better antidote to our economic woes than to rebuild our energy infrastructure based on technologies we create here, creating jobs that can’t be outsourced, paying domestic energy producers, removing the need to defend “our” resources in other countries, and a host of other benefits. Imagine if the unemployed were put to work producing clean energy capacity, which would benefit us for decades.

Our energy sources have trended toward less carbon and more hydrogen, starting with wood (C:H = 8:1), then coal (1:1), crude oil (1:2), and now natural gas (1:4). We can use our fossil-fuel wealth either to gracefully transition to a better future, or purely for current comfort and hope that we like the future created by others (e.g., the fossil-fuel industry).

I urge Princetonians, all of whom are leaders and opinion makers at some level, to take the precautionary principle to heart and take actions that are available to us now, will help reduce our climate-change impact, and make sense regardless of their impact on climate change.

Climate change is not a debate; it's a value – indeed, a responsive sensitivity to the environment that can only make the world a better place, spurring energy independence as a bonus, against which any fanatical objection undermines dreaming, loving, and a universal quest for global identity. Imprisoning these visions, in turn, paralyzes the greater good of imagination (shoring our shores, if you will).

For William Happer *64 to question “Temperatures Rising” (feature, March 17), how is game theory any less presumptuous than what Al Gore had invoked back when An Inconvenient Truth hadn’t yet upgraded a charged situation into something more inspiringly sustainable? Had it not been for Gore’s brave new bitter division, Mr. Happer’s alleged “scientific breakthrough” is nothing more than an unenlightened remand for the status quo of “settled assumptions” accepted over the millennia.

“Temperatures rising” is a disappointing example of the poor coverage climate science gets from journalists. The evasion “Professor Happer says X” is used to avoid discussing the merits of X — often, as in this case, leaving the impression that X is true. If PAW is incapable of determining the truth of X, then it ought to find the necessary expertise, readily available at Princeton. Just two examples:

1) “According to Happer, computer models developed by the IPCC ... fail to account for recent periods of global cooling.”

First, the IPCC is not in the business of developing models; its models are from the peer-reviewed literature. Is it plausible that the scientific community accepted them without testing on past data? If Happer can show that something’s wrong, why hasn’t he published a journal article, rather than arguing with Sen. Boxer? It’s absurd that these questions didn’t occur to PAW.

The earth cooled slightly from 1940–1970. This was a period of high sulfite aerosol pollution, which produces cooling, outweighing the warming from CO2.

Far from being ignored by scientists, this was IPCC report chapter 9. Lay readers can see “Attribution of recent climate change” on Wikipedia.

2) “[Stolen] e-mails ... seemed to suggest that researchers have modified data to support global warming theories ... ”

“Seemed to suggest” are weasel words — none of the accusations here stands up to scrutiny. No results were faked; no results have been called into question. The real scandal of “Climategate” was the media frenzy of lazy reporters repeating baseless charges, as PAW does here.

Our grandchildren will wonder why we failed to take action when the science of climate was clear. Poor journalism will get much of the blame. PAW has done some great reporting on climate science at Princeton. It is a shame that it failed here.

“Temperatures rising” (feature, March 17) outlines views about climate and climate change from four Princeton faculty members who are global-warming skeptics. The information in many quotes and paraphrased statements from these scientists is wrong. This letter corrects the most serious errors.

Perhaps the most egregious error is the statement that “human activity has little to do with rising CO2 levels.” There is redundant and overwhelming scientific evidence, from our work and that of many other scientists, that the ongoing increase in the CO2 concentration of air is essentially all anthropogenic, and mostly due to burning of fossil fuels (some is from deforestation).   The atmospheric CO2 concentration, known from ice-core studies to be roughly constant at 270 ppm (parts per million) from 10,000 years ago to 1800 A.D., has since risen to 385 ppm. Isotopic studies, which fingerprint the CO2 source, show that the rise is due mainly to burning fossil fuels.   The geographic pattern of CO2 concentration changes in air shows the same.  

Second, the idea that “plants and early humans … evolved when CO2 levels were about 1,000 parts per million” goes beyond what can be supported by observations and is partly inconsistent with the data where we do have them. We have only the vaguest idea of CO2 concentrations as plants evolved hundreds of millions or billions of years ago. Ironically, the best evidence for high CO2 is that we simply cannot explain what kept the Earth from freezing over during much of this time, when the sun shone less brightly than today, unless we assert the existence of a powerful greenhouse effect. When Homo sapiens evolved, about 200,000 years ago or later, CO2 was between 180 to 290 ppm. This we know definitively from studies of fossil air in ice cores. If we go back to the time of the last common ancestor of humans and chimpanzees, perhaps 7 million years ago, indirect evidence suggests that CO2 was 250 to 400 ppm. There is no evidence for levels around 1,000 ppm then, or at any intervening time.  

Third, contrary to a skeptic’s view, climate-change scientists hardly “ignore the fact … that temperatures in fact cooled during the period from roughly 1940 to 1970.” This cooling, of about 0.2˚F, has received extensive attention from climate scientists around the world, including some of us. The dominant cause is still uncertain, but natural fluctuations of the climate system probably played a role. These natural fluctuations are likely to be large enough to occasionally mask a decade or two of warming due to increasing levels of CO2, but not to negate the long-term trend. Such fluctuations are also seen in climate-model projections.

Fourth, it is not correct to say that “(sea levels) have been rising since the end of the last Ice Age, and there is no evidence that the rate is increasing.” Nearly all of the sea-level rise from the demise of the great ice sheets had occurred by 8,000 years ago. We know, from measurements, that sea level is now rising at the rate of more than 20 cm/century (8 inches/century), at least five times higher than the average rise (if any) of the past 4,000 years.  

Fifth, the IPCC does not “develop” climate models, as was stated incorrectly. The most elaborate climate models are developed by about 20 laboratories around the world. This effort is anything but monolithic, and there is a wide range of projections about how much warming we can expect from a given CO2 increase. Hundreds of other researchers collect and analyze data, or work on climate models or theories that focus on specific aspects of the climate system. The role of the IPCC is to review the relevant literature and assemble information from climate models and many other ways of studying the climate system, to provide the best explanations for climate changes in the recent past, and to make the best estimates of the consequences of different emissions scenarios for the future.

Sixth, the idea that “CO2 levels have been much higher in the past, but this did not induce a tipping point …” has no basis in the available evidence. According to our best indirect estimates, CO2 was about 1,000 ppm (with a large uncertainty) from about 170 million until 30 to 35 million years ago, when it fell near-present levels. This high-CO2 world at times had polar temperatures about 20˚F warmer than present, equatorial temperatures 10˚F warmer than present, and sea level about 200 feet higher than present (for reference, Princeton is 215 feet above sea level). Recent research has determined that, during an extraordinary high-CO2 event about 55 million years ago, seawater temperatures on the Jersey Shore reached nearly 90˚F (about 18˚F warmer than now). Clearly, the high-CO2 world of past times was very different from today’s.

The list above is by no means a complete summary of climate skeptics’ statements in the article with which we disagree.

Two things should give the Princeton community concern about the judgment of the climate skeptics described in PAW. The first is the many errors in what they present as facts. The second is the loss of objectivity exemplified by Dr. Happer’s quote about climate scientists who believe that carbon dioxide causes global warming : “This is George Orwell. This is the ‘Germans are the master race. The Jews are the scum of the earth.’ It’s that kind of propaganda.”

Editor’s note: A condensed version of this letter was published in the April 28, 2010, issue of PAW. Isaac Held is a climate scientist who is senior scientist at the NOAA Geophysical Fluid Dynamics Laboratory and lecturer with rank of professor in the Atmospheric and Oceanic Sciences Program. The other signers are climate scientists and carbon cycle scientists who are senior Princeton faculty members in the Atmospheric and Oceanic Sciences Program, Woodrow Wilson School, and the departments of civil and environmental engineering, ecology and evolutionary biology, and geosciences.