Unless emissions of greenhouse gases from the burning of fossil fuels are sharply curtailed, the latest computer models of climate change show that by 2100 or so, the United States could be a hotter and wetter place. As a result, most of the country could face a dramatic decrease in vegetation, as shown in the large map below, produced by Ron Neilson of Oregon State University. Brown areas reflect a decrease of 50 percent or more in the quantity of growing plants in a given area, compared with the present. As shown in the smaller map, above, some areas may first experience an increase in vegetation in the middle of the century, followed by a sharp decline. 2100 or later .
Scenarios vary widely.
However, large amounts of dry land could be lost by 2100 with a 20-inch rise in sea level, considered likely by that date. This assumes that no protective meas- ures such as sea walls are created. Climate at the end of the 21st century Rainfall patterns may increase in some parts of the world and decrease in others, but most climate models predict that virtually all of the United States will see wetter conditions. While temperatures are expected to rise almost everywhere, some places and some seasons will experience greater increases than others.