Forest pests also might create disturbances. Some insects are already expanding their ranges. Camille Parmesan of the University of Texas at Austin and her colleagues studied 35 species of nonmigratory butterflies in Europe, and found that more than half shifted their range north during the last century. More movement among animals surely lies ahead. For birds and for mammals, the prediction was that in southern portions of the U.S. the richness would drop fairly substantially, due to the heat exceeding current tolerances.
Scientists also see signs of climate-induced changes in forests.
One compelling example comes from Ranga Myneni's laboratory at Boston University. Using satellite images, he found the growing season for trees in the northern United States increased by nearly two weeks from 1981-1991. Foremost, conserving energy and buying more fuel-efficient devices will reduce the use of fossil fuel. Planting trees also helps. According to the Heat Island Group, strategically planted trees in cities can reduce heating and cooling costs by 10 to 20 percent.