“{...}
. . . (what) I found in examining the views of climate skeptics is that they are scattered widely in blogs, talks, and pamphlets.
Then, I saw an opinion piece in The Wall Street Journal of January 27, 2012, by a group of sixteen scientists, entitled “No Need to Panic About Global Warming.” . . .
The basic message of the article is that the globe is not warming, that dissident voices are being suppressed, and that delaying policies to slow climate change for fifty years will have no serious economic or environment consequences.
My response is primarily designed to correct their misleading description of my own research; but it also is directed more broadly at their attempt to discredit scientists and scientific research on climate change. [.1]
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Professor Nordhaus identified six key issues that are raised in the article, and provides commentary about their substance and accuracy.
They are:
• Is the planet in fact warming?
• Are human influences an important contributor to warming?
• Is carbon dioxide a pollutant?
• Are we seeing a regime of fear for skeptical climate scientists?
• Are the views of mainstream climate scientists driven primarily by the desire for financial gain?
• Is it true that more carbon dioxide and additional warming will be beneficial?
{He goes on to explain. }
"... of these questions, the sixteen scientists provide incorrect or misleading answers. At a time when we need to clarify public confusions about the science and economics of climate change, they have muddied the waters. I will describe their mistakes and explain the findings of current climate science and economics.{...}
written by Dr. William D. Nordhaus
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# 6.
A final point concerns economic analysis. The sixteen scientists argue, citing my research, that economics does not support policies to slow climate change in the next half-century:
“A recent study of a wide variety of policy options by Yale economist William Nordhaus showed that nearly the highest benefit-to-cost ratio is achieved for a policy that allows 50 more years of economic growth unimpeded by greenhouse gas controls. This would be especially beneficial to the less-developed parts of the world that would like to share some of the same advantages of material well-being, health and life expectancy that the fully developed parts of the world enjoy now. Many other policy responses would have a negative return on investment. And it is likely that more CO2 and the modest warming that may come with it will be an overall benefit to the planet.”
On this point, I do not need to reconstruct how climate scientists made their projections, or review the persecution of Soviet geneticists. I did the research and wrote the book on which they base their statement. The skeptics’ summary is based on poor analysis and on an incorrect reading of the results.
The first problem is an elementary mistake in economic analysis. The authors cite the “benefit-to-cost ratio” to support their argument. Elementary cost-benefit and business economics teach that this is an incorrect criterion for selecting investments or policies. The appropriate criterion for decisions in this context is net benefits (that is, the difference between, and not the ratio of, benefits and costs).
This point can be seen in a simple example, which would apply in the case of investments to slow climate change. Suppose we were thinking about two policies. Policy A has a small investment in abatement of CO2 emissions. It costs relatively little (say $1 billion) but has substantial benefits (say $10 billion), for a net benefit of $9 billion. Now compare this with a very effective and larger investment, Policy B. This second investment costs more (say $10 billion) but has substantial benefits (say $50 billion), for a net benefit of $40 billion. B is preferable because it has higher net benefits ($40 billion for B as compared with $9 for A), but A has a higher benefit-cost ratio (a ratio of 10 for A as compared with 5 for B). This example shows why we should, in designing the most effective policies, look at benefits minus costs, not benefits divided by costs.
This leads to the second point, which is that the authors summarize my results incorrectly. My research shows that there are indeed substantial net benefits from acting now rather than waiting fifty years. A look at Table 5-1 in my study A Question of Balance (2008) shows that the cost of waiting fifty years to begin reducing CO2 emissions is $2.3 trillion in 2005 prices. If we bring that number to today’s economy and prices, the loss from waiting is $4.1 trillion. Wars have been started over smaller sums, [.10]
My study is just one of many economic studies showing that economic efficiency would point to the need to reduce CO2 and other greenhouse gas emissions right now, and not to wait for a half-century. Waiting is not only economically costly, but will also make the transition much more costly when it eventually takes place. Current economic studies also suggest that the most efficient policy is to raise the cost of CO2 emissions substantially, either through cap-and-trade or carbon taxes, to provide appropriate incentives for businesses and households to move to low-carbon activities.
One might argue that there are many uncertainties here, and we should wait until the uncertainties are resolved. Yes, there are many uncertainties. That does not imply that action should be delayed. Indeed, my experience in studying this subject for many years is that we have discovered more puzzles and greater uncertainties as researchers dig deeper into the field. There are continuing major questions about the future of the great ice sheets of Greenland and West Antarctica; the thawing of vast deposits of frozen methane; changes in the circulation patterns of the North Atlantic; the potential for runaway warming; and the impacts of ocean carbonization and acidification.
Moreover, our economic models have great difficulties incorporating these major geophysical changes and their impacts in a reliable manner. Policies implemented today serve as a hedge against unsuspected future dangers that suddenly emerge to threaten our economies or environment. So, if anything, the uncertainties would point to a more rather than less forceful policy—and one starting sooner rather than later—to slow climate change.
The group of sixteen scientists argues that we should avoid alarm about climate change. I am equally concerned by those who allege that we will incur economic catastrophes if we take steps to slow climate change. The claim that cap-and-trade legislation or carbon taxes would be ruinous or disastrous to our societies does not stand up to serious economic analysis. We need to approach the issues with a cool head and a warm heart. And with respect for sound logic and good science.
—February 22, 2012
http://nordhaus.econ.yale.edu/biosketch1.htm
William D. Nordhaus is Sterling Professor of Economics at Yale University, New Haven, Connecticut, USA.
Completed his undergraduate work at Yale University in 1963 and received his Ph.D. in Economics in 1967 from the Massachusetts Institute of Technology, Cambridge, USA.
Has been on the faculty of Yale University since 1967 and has been Full Professor of Economics since 1973.
Is also Professor in Yale’s School of Forestry and Environmental Studies.
