A brief look at main findings of the Intergovernmental Panel on Climate
THE CAUSE: Global warming is "very likely" caused by man — the strongest
conclusion to date. Concentrations of heat-trapping greenhouse gases in the
planet's atmosphere "have increased markedly as a result of human activities
since 1750," mainly from the use of fossil fuels like oil, gas and coal, and
because of agriculture.
THE OUTLOOK: Now that the world has begun to warm, hotter temperatures and rises
in sea level "would continue for centuries" no matter how much humans control
their pollution. It is "very likely" that heat waves, hot weather, and heavy
rainfalls "will continue to become more frequent." Toward the end of this
century, sea ice in the Arctic may disappear "almost entirely" in summer.
TEMPERATURE CHANGE: Predicted temperature rises of 1.1 to 6.4 C (2-11.5 F) by
the year 2100. That is a wider range than in a 2001 report. The panel said its
best estimate was for temperature rises of 1.8 to 4 C (3.2-7.1 F). Scientists
said they are more sure of temperature increases than ever before and the
difference between the previous report and now should not be interpreted that
global warming will be less of a problem than thought in 2001.
SEA LEVELS: Projects rises of 7-23 inches (18-58 centimeters) by the end of the
century. An additional 3.9-7.8 inches (10-20 centimeters) are possible if
recent, surprising melting of polar ice sheets continues.
HURRICANES: An increase in hurricane and tropical cyclone strength since 1970
"more likely than not" can be attributed to man-made global warming. Scientists
said global warming's connection varies with storms in different parts of the
world, but that the storms that strike the Americas are global
Man-made factors have "likely" contributed to changes in wind patterns. It also
is "likely" that typhoons and hurricanes will become more intense, with stronger
winds and heavier rains.