Global Warming

Variations in the energy output of the sun, changes in the relative positions of the sun and Earth, shifting locations of the continents, volcanic eruptions, and other alterations of atmospheric composition all combine to cause climate change. The long term changes in Earth's temperatures are encompassed within a range of natural variability. However, global warming refers to the relatively rapid, recent changes that are outside this range of natural variability. The mean global temperature of Earth has not deviated more than 1 degree Celsius from the average since the beginning of civilization. By 2100, Earth's temperature is forecast to increase from 1.5 to 4 degrees Celsius if present rates of warming continue. This rate of temperature increase is unequivocal in that it has no equal ...