Global Warming, Global Warning.

• Author: HOWELL, LLEWELLYN D.

SHOULD GLOBAL WARMING be of concern to Americans? Here's one indication. A Yahoo! search on the Internet results in more than 150,000 citations of websites with something to say about the issue. Points of view range from alarm to complete dismissal. Most are nearer to the alarm end of the spectrum, but, apart from the balance of advocates and opponents, whom should be believed?

Greenhouse gases are at the source of the atmospheric impenetrability that keeps heat inside the Earth's envelope. Carbon dioxide ([CO.sub.2]) from automobiles and power plants is the primary source of gases that create the greenhouse effect. Rising temperatures and melting ice will alter the climate in such a way that it will negatively affect many forms of life, especially human. If this is so, isn't it necessary to take action to cut back on travel by automobile and industrial pollution (and therefore some production) in order to protect future generations? If so, whose emissions should be cut--the U.S.'s or those of developing countries like China that are trying to increase domestic production rapidly? Shouldn't population growth be limited to slow the rise in the number of contributing polluters?

What are the agreed-on manifestations of the problem? A major one is that Arctic ice is diminishing and has been doing so for the last several decades. A University of Washington study, with data from U.S. nuclear submarines plying the Arctic Ocean, shows that Arctic ice is 40% thinner than it was in the 1950s and appears to be thinning at a rate of about four inches per year. While there can be some thinning as a result of natural atmospheric behavior, this development looks to be facilitated by human-generated global warming.

This conclusion is supported by computer modeling at the NASA Goddard Center for Space Studies in New York. The models indicate that a buildup of heat-trapping greenhouse gases is largely responsible for the melting ice. This melting ice can change ocean currents, which can alter the climate anywhere or everywhere on the planet. Because of melting ice, especially that above the surface, oceans are projected to rise seven to 37 inches in the next century, and the higher water is already washing away beaches along U.S. coasts.

Meanwhile, increasing global temperatures are contributing to melting ice and being affected by it. The average surface temperature of the Earth rose about one degree Fahrenheit in the 20th century, and mainstream scientists...