Freeman Dyson on Global Warming

In the past here, I have written of many widespread criticisms of global warming by non-scientists, which I view as largely unhelpful and illegitimate. While I maintain that the uninformed opinions of so many pundits and politically-motivated, self-styled "experts" do not contribute to the debate over global warming, I do not want to give the impression that I do not take reasoned, useful criticisms seriously.

In this spirit, here are some well-thought, reasonable, and scientifically sound criticisms of the prevailing conception of global warming, by renowned physicist and mathematician Freeman Dyson. While Dyson is not primarily a climatologist, his extensive knowledge of physics and other scientific disciplines that contribute to climatology make his thoughts particularly relevant (from Wikipedia):

Dyson has questioned the predictive value of current computational models of climate change, urging instead more extensive use of local observations. He considers this view to be "heretical", along with his views on the PhD system.

The good news is that we are at last putting serious effort and money into local observations. Local observations are laborious and slow, but they are essential if we are ever to have an accurate picture of climate. The bad news is that the climate models on which so much effort is expended are unreliable because they still use fudge-factors rather than physics to represent important things like evaporation and convection, clouds and rainfall. Besides the general prevalence of fudge-factors, the latest and biggest climate models have other defects that make them unreliable. With one exception, they do not predict the existence of El Niño. Since El Niño is a major feature of the observed climate, any model that fails to predict it is clearly deficient. The bad news does not mean that climate models are worthless. They are, as Manabe said thirty years ago, essential tools for understanding climate. They are not yet adequate tools for predicting climate.^[14]

While he acknowledges climate change may be in part due to anthropogenic causes, such as the burning of fossil fuels, he regards the term "global warming" as a misnomer:

As a result of the burning of coal and oil, the driving of cars, and other human activities, the carbon dioxide in the atmosphere is increasing at a rate of about half a percent per year. … The physical effects of carbon dioxide are seen in changes of rainfall, cloudiness, wind strength, and temperature, which are customarily lumped together in the misleading phrase "global warming." This phrase is misleading because the warming caused by the greenhouse effect of increased carbon dioxide is not evenly distributed. In humid air, the effect of carbon dioxide on the transport of heat by radiation is less important, because it is outweighed by the much larger greenhouse effect of water vapor. The effect of carbon dioxide is more important where the air is dry, and air is usually dry only where it is cold. The warming mainly occurs where air is cold and dry, mainly in the arctic rather than in the tropics, mainly in winter rather than in summer, and mainly at night rather than in daytime. The warming is real, but it is mostly making cold places warmer rather than making hot places hotter. To represent this local warming by a global average is misleading, because the global average is only a fraction of a degree while the local warming at high latitudes is much larger.^[15]

Regarding political efforts to reduce the causes of climate change, Dyson argues that other global problems should take priority.

I'm not saying the warming doesn't cause problems, obviously it does. Obviously we should be trying to understand it. I'm saying that the problems are being grossly exaggerated. They take away money and attention from other problems that are much more urgent and important. Poverty, infectious diseases, public education and public health. Not to mention the preservation of living creatures on land and in the oceans.^[16]

These thoughts, especially those regarding the distribution of the the effects of global warming and the limitations of our climate modeling capabilities, are very relevant to our efforts to understand our world. Furthermore, Dyson's points show that global warming is, like all scientific predictions and possibly to a greater extent than most, far from being a well-established and definite phenomenon.

Dyson does not close-mindedly deny that climate changes are occurring within our world, and that these changes could have widespread effects. What he does do, however, is approach the task of understanding of these changes with a healthy regard for both the strengths and limitations of our current knowledge. Let Dyson serve as a model for those who seek to approach this issue fairly, rationally, and with regard for the truth rather than political convenience.