While Congress balks at ratifying the Kyoto Protocol on Climate Change unless developing countries sign on, and developing countries refuse to participate without the United States, scientists disagree about the severity of the long-range impact of greenhouse gases in the atmosphere.
Three speakers at the 1999 Catherine N. Stratton Lectures on Critical Issues took on the challenge of making sense of the science and policy state of affairs surrounding the protocol. The panel spoke on "Greenhouse Gamble: Responding to the Risk of Climate Change" to a full house in Wong Auditorium on October 6.
Ronald G. Prinn, the TEPCO Professor of Atmospheric Chemistry and chair of the Department of Earth, Atmospheric and Planetary Sciences, set the stage by outlining the latest thinking on climate change. Professor Prinn is also director of the Center for Global Change Science and co-director of the Joint Program on the Science and Policy of Global Change.
While there is no doubt that humans are influencing the climate by depleting the ozone layer, which leads to cooling of the upper part of the atmosphere, the question is whether they are influencing it significantly. Professor Prinn said natural fluctuations in climate change make it hard to tell.
"Climate oscillations occur. It's naturally a highly variable phenomenon," he said. In fact, there was a period in the earth's history when the temperatures were considerably warmer than today.
Yet when scientists look at climate oscillations over the past few hundred years, there's an odd-looking blip that occurs around 1850, where temperatures rise consistently until around 1940, cool until around 1970, then start to rise again. Researchers generally agree that this blip was caused by greenhouse gases tied to the Industrial Revolution.
The tendency for gases in the atmosphere to trap and re-emit heat toward the Earth is called the greenhouse effect. We're lucky it exists. Without it, the Earth would be 30-40ï¿½ï¿½ï¿½C colder.
But greenhouse gases in the atmosphere, which intensify the flow of radiant heat back to the surface, may be too much of a good thing. At the same time, tiny particles of aerosols produced by burning coal cool the Earth as they reflect sunlight back to space.
Experts' predictions range from an increase in global warming of 2 degrees over the next 100 years to an increase of 16 degrees. "If that one's correct, then we are in trouble," Professor Prinn said. "We are placing enormous risks with the natural system if this forecast is correct." Among the things that could occur is the melting of massive polar ice sheets, which would cause ocean levels to rise 5 meters.
Robert N. Stavins, the Albert Pratt Professor of Business and Government and faculty chair of the Environment and Natural Resources Program at Harvard's John F. Kennedy School of Government, noted that the Kyoto protocol -- an agreement negotiated almost two years ago to slow global warming -- attempts to address an exceptionally difficult problem. In essence, it is asking voters in America to protect the next generation in developing countries, while American voters tend to pass our own national problems on to our own next generation.
Kyoto doesn't specify long-term goals and it doesn't have any international institution that would enforce it, but it is a first step, Professor Stavins said.
"We need a greater public understanding of this problem," he said. "It won't cost nothing [to fix] and it also won't cause economic catastrophe. We need to see the real benefits and the real costs. [Kyoto] needs to overcome political obstacles to action."
Providing perspective on some of those political obstacles was Eileen Clausen, executive director of the Pew Center on Global Climate Change. She is also a former assistant secretary of state for oceans and international environmental and scientific affairs and former special assistant to the President and senior director for Global Environmental Affairs at the National Security Council.
Ms. Clausen said that Kyoto is a "political deal that is unlikely to happen in time for the first set of target reductions" in 2008. "The current mood in the United States will not result in ratification of the Kyoto protocol."
In developing countries, she pointed out, climate change is less of a priority than air and water pollution. In addition, developing countries won't want to limit their economic development, and they say that the United States is by far the worst offender.
On a positive note, Ms. Clausen said the American public and corporations are increasingly recognizing the significance of the climate change issue. Some companies have already taken aggressive actions to reduce emissions. DuPont, for example, has promised a 65 percent reduction in emissions before 2010, which is far in excess of the 7 percent reduction required of the United States as a whole.
A version of this article appeared in MIT Tech Talk on October 27, 1999.