Earth's last gasp?

• Author: Lashof, Daniel A.

". . . Entrenched special interests,, such as the coal and oil industries, can be expected to use every tool at their disposal to fight sensible climate policies, regardless of the broad-scale benefits for the economy and the environment."

When coal, oil, and natural gas are burned to generate electricity, drive automobiles, run factories, and heat homes, the atmosphere is polluted with carbon dioxide, a gas that traps heat like the glass panes of a greenhouse. Scientists have been observing the buildup of carbon dioxide and other so-called greenhouse gases in the atmosphere for decades with increasing interest and concern. Net, the problem of human-induced global climate change, or global warming, didn't emerge onto the public agenda until 1988. When a string of unusually hot weather. coupled with the Congressional testimony of NASA scientist Jim Hansen proclaiming a high degree of confidence" that humans already were changing the Earth's climate, garnered headlines around the country.

During the following four years, a string of record temperatures and high-profile reports kept global warming in the headlines. This intense period of publicity and diplomatic activity culminated in the Earth Summit at Rio de Janeiro in June, 1992, where 150 nations signed the Rio Climate Treaty, committing themselves to preventing "dangerous" interference with the climate system.

A combination of factors conspired to move global warming off the front pages following the Earth Summit. Media coverage and Congressional concern seem to be driven more by how hot it was last summer in the eastern U.S. (less than one percent of the planet's surface) than by long-term global warming trends and considered scientific opinion. When particles injected into the stratosphere by the Mt. Pinatubo volcanic eruption in the Philippines in June, 1991, temporarily cooled global temperatures by about 0.5 [degrees]C, this apparently took the heat off policymakers as well.

Recently, though, the climate issue has made a comeback. By the end of 1994, the Pinatubo plume almost completely had settled, and global temperatures returned to record levels in 1995, just as climate models had predicted at the time of the eruption. Meanwhile, an international panel involving around 2,500 scientists from 130 countries quietly had been preparing an updated assessment of climate change. When the Intergovernmental Panel on Climate Change (IPCC) adopted its final report in the fall of 1995, it made headlines around the world for the conclusion that "the balance of evidence suggests a discernible human influence on global climate." Thus, the consensus of the international scientific community confirms Hansen's testimony, which had helped to launch climate change as a public issue seven years earlier. The panel report also included the following:

Rapid climate change. The average rate of warming over the next century probably will be greater than any seen in the last 10,000 years if global warming pollution is not controlled. Extrapolating from a wide range of scenarios for future pollutant emissions and the scientists" range of uncertainty about how the climate will respond to a given change in greenhouse gas concentrations, global mean temperature is projected to rise by 1.8 to 6.3 [degrees]F between 1990 and 2100.

Death and disease. More than 500 deaths were...