The Science and Economics of Climate Change
July 10, 1997

This morning, we will receive testimony on one of the most important and challenging environmental, economic and political matters of our time... global climate change. It is a serious issue that requires immediate attention.

To help us better understand some of the fundamental scientific and economic issues which underpin the current policy debate, we have assembled some of the world's leading experts. The full Committee will conduct a follow-up hearing one week from today, on July 17, to receive testimony from the Administration on the upcoming international negotiations over amendments to the 1992 Framework Convention on Climate Change.

The issue of global climate change is politically contentious both here and abroad. Some say that climate science, too, is a matter of great debate . . . great uncertainty.

For years now, we have had one side forecasting a scenario of rising seas, recurrent drought and blistering heat -- all of which, they say, will result in a ravaged economy. On the other side are those who claim that meaningful policies to control emissions of greenhouse gases are premature, unwarranted and unfounded -- and will result in a ravaged economy.

What is going on here? What are the scientists saying? Consider this quotation: "Would it not be possible that the Earth's temperature had decreased during periods of low carbon dioxide and increased when the protective carbon dioxide had been present to a higher degree?"

As our distinguished witnesses are aware, this hypothesis was not culled from the text of some suspect environmental organization's manifesto. It was delivered in an 1896 lecture -- one hundred and one years ago -- before the Stockholm Physics Society by the Nobel Prize-winning Swedish chemist, Svante Arrhenius.

Professor Arrhenius was the first to predict that large increases in carbon dioxide from humans could result in a warming of the globe. What have the world's scientists bold us at different intervals over the last one hundred and one years, since Professor Arrhenius first identified the warming effects of carbon dioxide? Here is just a sampling.

1924 - A U.S. physicist speculated that industrial activity would double atmospheric carbon dioxide within five hundred years, roughly, the year 2424, (Current projections are for a doubling sometime before 2050 - four hundred years earlier than predicted seventy years ago!)

1957 - Scientists from the Scripps Institute of Oceanography reported for the first time that much of the carbon dioxide emitted into the atmosphere is not absorbed by the oceans as some had argued, leaving significant amounts in the atmosphere. They are said to have called carbon dioxide emissions a "large-scale geophysical experiment" with the Earth's climate.

1967 - The first reliable computer simulation calculated that global average temperatures may increase by more than four degrees Fahrenheit when atmospheric carbon dioxide levels are double that of pre-industrial times.

1985 - A conference sponsored by the U.N. Environment Program (UNEP), the World Meteorological Organization (WMO), and the International Council of Scientific Unions forged a consensus of the international community on the issue of climate change. The conference report warned that some future warming appears inevitable due to past emissions, regardless of future actions, and recommended consideration of a global treaty to address climate change.

1987 - An ice core from Antarctica, analyzed by French and Russian scientists, revealed an extremely close correlation between carbon dioxide and temperature going back more than one hundred thousand years.

1990 - An appeal signed by more than forty-nine Nobel Prize winners and seven hundred members of the National Academy of Sciences stated, "There is broad agreement within the scientific community that amplification of the Earth's natural greenhouse effect by the buildup of various gases introduced by human activity has the potential to produce dramatic changes in the climate... Only by taking action now can we ensure that future generations will not be put at risk."

Also in 1990 - seven hundred and forty-seven participants from one hundred sixteen countries took part in the Second World Climate Conference in Geneva, Switzerland. The conference statement reported that, "...if the increase of greenhouse gas concentrations is not limited, the predicted climate change would place stresses on natural and social systems' unprecedented in the past ten thousand years."

1992 - While not a scientific development, it must be noted that this was the year that the United States and one hundred and fifty-three other nations signed the so-called "Framework Convention on Climate Change" at the U.N. Conference on Environment and Development. This U.N. Conference, otherwise known as "the Earth Summit," was of course held in Rio de Janeiro.

The 1992 Framework Convention on Climate Change, which commits signatories' governments to voluntary reduction of greenhouse gases, was viewed at the time as a scientifically-sound first step toward a proactive stabilization of atmospheric greenhouse gas concentrations. The Senate consented to ratification of this landmark environmental treaty on October 7, 1992, with a two-thirds majority division vote.

1995 - The Intergovernmental Panel on Climate Change, representing thousands of climate scientists worldwide, concluded that, "...the balance of evidence suggests that there is a discernible human influence on global climate."

It must be stated that the most recent IPCC conclusion is based on numerous variables. I am eager to learn more about these variables -- and about the certainties from our witnesses.

So we will hear today about this evolution of scientific understanding. I am convinced that the science on this matter has and will continue to evolve. The question is, do we know enough to support legally binding reductions in greenhouse gas emissions -- as is proposed by the United States and numerous other countries? Moreover, are we prepared to accept the risks associated with the decision to postpone further action to address potential climate change?

What is being called for? What might the impacts to our economy be? Some say that we must stabilize carbon dioxide emissions at 1990 levels by the year 2010. At least one economic model forecasts that this sort of action would result in economic losses of about 2.4 percent in GDP in the year 2020. This, of course, would be significant.

Others, using more optimistic models and assumptions, believe that the U.S. economy could withstand significant emissions reductions while prospering as never before. Some twenty-five hundred economists declared in February of this year that cost effective means are available for the United States to address the threat of climate change.

Let me conclude by identifying what I see as the fundamental questions before us today. First, how much warming might occur as a result of human actions? And, how soon might such warming occur? Next, what is the range of impacts and when' might they be conclusively identified? Finally, what do economic modeling and empirical data tell us about various policy responses?"