Abstract
For mote than a decade, scientists around the world have expressed concern over observed changes in the Earth's environment that suggest fum global environmental problems. They have documented increased levels of air pollutants such as ozone nd acid I as well as in- in carbon dioxide and other greenhouse gases. Scientists also have noted a 0.5°F to l.0°F rise in mean surface airtempem over the past 100 years, with the five warmest years on record occuring in the 1980s and `90s. And they have recorded a 4- to 8-inch rise in mean sea level over the same period. The changes in the chemical clirnate--the increases in catbon dioxide and air pollutants--can be linked to human activities such as fossil fuel combustion. There is concern that chemical climate changes ate causing, or will cause, changes in the physical climate. Uncertainties exist about the extent to which human activities can be linked to the recent warning trend. Some members of the scientitic community argue that the changes in tempemture and sea level am simply natural variations. Long periods of unusually warm weather have been mrded in the past; however it is known that the socalled gnmhouse gases contribute to a warming of the Earth and the atmospheric concentrations of these gases are inming. Pdictions ftom global-scale geneml circulation models suggest that over the next century the planet's physical climate will change at an unprecedented rate. The gmving consensus among scientists is that, because of human activities, global conditions are changing in ways, and at rates, that will have profound effects on humans and on natural ecosystems.
Citation
Southeastern Forest Experiment Station 1992. The southern global change program. Gen. Tech. Rep. SE-79. Asheville, NC: U.S. Department of Agriculture, Forest Service, Southeastern Forest Experiment Station. 32 p.
