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. 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.
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.