National Geographic Oct 1990

Is Our World Warming?

Under the SUN

For more than four billion years the sun and the earth itself have been the driving forces in our planet's changing climate. Now we puny humans — in all our billions — may have become the decisive force for change in the decades ahead.

By Samuel W. Matthews, Senior Assistant Editor Photographs by JAMES A. SUGAR, Black Star

The power of sunlight captured millions of years ago by plants and animals and buried in huge deposits is now being burned as coal, petroleum, and natural gas. Such burning in power stations, automobiles, and homes releases carbon dioxide (CO2) to the air. Once airborne, CO2 absorbs heat, warming the atmosphere in the so-called greenhouse effect.