President Obama is so convinced about dangerous human-caused global warming that he describes sceptics as ‘flat-earthers’ who think the moon is made of cheese. Actually, sceptics include three astronauts who have walked on the moon — Buzz Aldrin, Charles Duke and Jack Schmidt — and four other Apollo astronauts. But let’s not quibble with the president, who claims to have the weight of the science community behind him.
Or does he? Dr Steven E. Koonin (inset) was Undersecretary for Science in the Energy Department during Obama’s first term. Koonin is sceptical about the alarmist case, so much so that he calls for serious independent reviews of the IPCC’s forecasts and methodology, along with a close look at other scientists’ prognostications.
He says, “A transparent rigor would be a welcome development, especially given the momentous political and policy decisions at stake. That could be supported by regular, independent, ‘red team’ reviews to stress-test and challenge the projections by focusing on their deficiencies and uncertainties; that would certainly be the best practice of the scientific method.”
Koonin’s previous positions include professor of theoretical physics and provost at Caltech, as well as chief scientist of BP, where his work focused on renewable and low-carbon energy technologies.
Writing in Saturday’s Wall Street Journal on Saturday Koonin debunked warmism, saying it would be a long time before science could give validly emphatic advice to the political community. The certitude of the orthodox climate scientist was not only misguided, he continued, but was distorting the debate on energy and CO2 emissions.
Koonin’s arguments are basically a primer of the sceptic position: Yes, climate is always changing. Yes, humans influence climate through CO2 emissions and other activities. Human activity may even have a climate impact comparable to natural climate variability. Koonin continues, “The crucial, unsettled scientific question for policy is, ‘How will the climate change over the next century under both natural and human influences?’
“Even though human influences could have serious consequences for the climate, they are physically small in relation to the climate system as a whole. For example, human additions to carbon dioxide in the atmosphere by the middle of the 21st century are expected to directly shift the atmosphere’s natural greenhouse effect by only 1% to 2%.
“Since the climate system is highly variable on its own, that smallness sets a very high bar for confidently projecting the consequences of human influences.”
Koonin says that a second challenge to “knowing” future climate is today’s poor understanding of the oceans, which strongly influence the atmosphere. Unfortunately, precise and comprehensive observations of the oceans are available only for the past few decades; the reliable record is still far too short to adequately understand how the oceans will change and how that will affect climate.
“A third fundamental challenge arises from feedbacks that can dramatically amplify or mute the climate’s response to human and natural influences. One important feedback, which is thought to approximately double the direct heating effect of carbon dioxide, involves water vapor, clouds and temperature.
“But feedbacks are uncertain. They depend on the details of processes such as evaporation and the flow of radiation through clouds. They cannot be determined confidently from the basic laws of physics and chemistry, so they must be verified by precise, detailed observations that are, in many cases, not yet available,” Koonin says.
A further fundamental problem with climate science involves the complex computer models used to project future climate. “While some parts of the models rely on well-tested physical laws, other parts involve technically informed estimation. Computer modeling of complex systems is as much an art as a science,” he observed. The models require many assumptions to be inputted to ‘tune’ the models to reality, such as assumptions about cloud cover and past historical changes. “We often hear that there is a ‘scientific consensus’ about climate change. But as far as the computer models go, there isn’t a useful consensus at the level of detail relevant to assessing human influences.”
The latest 2013 IPCC report uses an ensemble of 55 tuned models. Konin points out that “the marked differences in their details and projections reflect all of the limitations”. For example,
“The models differ in their descriptions of the past century’s global average surface temperature by more than three times the entire warming recorded during that time. Such mismatches are also present in many other basic climate factors, including rainfall, which is fundamental to the atmosphere’s energy balance. As a result, the models give widely varying descriptions of the climate’s inner workings. Since they disagree so markedly, no more than one of them can be right.”
On the halt in warming this century, Koonin says that although the Earth’s average surface temperature rose sharply, by 0.9 degree Fahrenheit, during the last quarter of the 20th century, it has increased much more slowly for the past 16 years, even as the human contribution to atmospheric carbon dioxide has risen by some 25%. “This surprising fact demonstrates directly that natural influences and variability are powerful enough to counteract the present warming influence exerted by human activity.
“Yet the models famously fail to capture this slowing in the temperature rise. Several dozen different explanations for this failure have been offered, with ocean variability most likely playing a major role. But the whole episode continues to highlight the limits of our modeling.
“The models roughly describe the shrinking extent of Arctic sea ice observed over the past two decades, but they fail to describe the comparable growth of Antarctic sea ice, which is now at a record high.
“The models predict that the lower atmosphere in the tropics will absorb much of the heat of the warming atmosphere. But that ‘hot spot’ has not been confidently observed, casting doubt on our understanding of the crucial feedback of water vapor on temperature.
“Even though the human influence on climate was much smaller in the past, the models do not account for the fact that the rate of global sea-level rise 70 years ago was as large as what we observe today—about one foot per century.
“A crucial measure of our knowledge of feedbacks is climate sensitivity—that is, the warming induced by a hypothetical doubling of carbon-dioxide concentration. Today’s best estimate of the sensitivity (between 2.7 degrees Fahrenheit and 8.1 degrees Fahrenheit) is no different, and no more certain, than it was 30 years ago. And this is despite an heroic research effort costing billions of dollars.”
Koonin says that these and many other open questions are in fact described in the IPCC research reports, although a detailed and knowledgeable reading is sometimes required to discern them. They are not ‘minor’ issues to be ‘cleaned up’ by further research. Rather, they are deficiencies that erode confidence in the computer projections. Work to resolve these shortcomings in climate models should be among the top priorities for climate research.
“Yet a public official reading only the IPCC’s ‘Summary for Policy Makers’ would gain little sense of the extent or implications of these deficiencies. These are fundamental challenges to our understanding of human impacts on the climate, and they should not be dismissed with the mantra that ‘climate science is settled.”
While the past two decades have seen progress in climate science, the field is not yet mature enough to usefully answer the difficult and important questions being asked of it. This decidedly unsettled state highlights what should be obvious: Understanding climate, at the level of detail relevant to human influences, is a very, very difficult problem, he says.
Koonin says that we can and should take steps to make climate projections more useful over time. An international commitment to a sustained global climate observation system would generate an ever-lengthening record of more precise observations. The science is urgent, since we could be caught flat-footed if our understanding does not improve more rapidly than the climate itself changes.
Because the natural climate changes over decades, it will take many years to get the data needed to confidently isolate and quantify the effects of human influences.
“Rigidly promulgating the idea that climate science is ‘settled’ (or is a ‘hoax’) demeans and chills the scientific enterprise, retarding its progress in these important matters. Uncertainty is a prime mover and motivator of science and must be faced head-on. It should not be confined to hushed sidebar conversations at academic conferences.
“Society’s choices in the years ahead will necessarily be based on uncertain knowledge of future climates. That uncertainty need not be an excuse for inaction. There is well-justified prudence in accelerating the development of low-emissions technologies and in cost-effective energy-efficiency measures.
“But climate strategies beyond such ‘no regrets’ efforts carry costs, risks and questions of effectiveness, so nonscientific factors inevitably enter the decision. These include our tolerance for risk and the priorities that we assign to economic development, poverty reduction, environmental quality, and intergenerational and geographical equity.
“Despite the statements of numerous scientific societies, the scientific community cannot claim any special expertise in addressing issues related to humanity’s deepest goals and values. The political and diplomatic spheres are best suited to debating and resolving such questions, and misrepresenting the current state of climate science does nothing to advance that effort.
“Any serious discussion of the changing climate must begin by acknowledging not only the scientific certainties but also the uncertainties, especially in projecting the future. Recognizing those limits, rather than ignoring them, will lead to a more sober and ultimately more productive discussion of climate change and climate policies. To do otherwise is a great disservice to climate science itself.”
Tony Thomas blogs at tthomas061.wordpress.com