In the Arctic and Antarctic, the area of sea ice has decreased 10 to 15 percent in about 20 years. A review of scientific literature by one of the international report's lead authors found that 40 percent of the world's ecosystems were already showing previously predicted effects of global warming, MacCracken said. While most scientists agree that global warming is real, human-caused and a threat, the Bush administration is not so sure. There is still disagreement as to the causes and the long-term future. Global warming is not necessarily bad, Paynter added.
Carbon dioxide is a plant nutrient.
It is not a pollutant. Scientists from other countries, particularly Europeans pressing the United States to cut back emissions, say the evidence of a real problem is overwhelming. In Southern Europe, episodic flooding but generally declining rainfall will cause farmland to deteriorate. In Asia, deserts will increase in size and scope while more and more serious monsoons devastate low-lying areas. In Africa, declining rainfall will cause deserts to increase, crops to fail and hydroelectric power production to fall.