A closer look at the issue reveals a surprising lack of evidence for a global crisis. It is true that CO2 and methane levels have increased slightly, and that this increase may be due to man's efforts, but predictions of global warming are based on theory alone, and most of these theories predict mild increases in average temperature. All of the scientific evidence gathered indicated that there is no danger of a global warming disaster.
Earth's average temperatures tend to fluctuate over long term cycles. Earth has been considerably warmer in the past than it is now. For example, from AD 900 to AD 1100, a period scientists refer to as the "Medieval Climate Optimum," global temperatures were warmer on average than at present. The weather was so mild that the Vikings established colonies and farms in Greenland (in regions that were, in fact, green). In the 1300s, however, global temperatures began to drop, plunging the world into the Little Ice Age. The Vikings' crops and livestock in Greenland began to fail, the Vikings left, and Greenland was covered with ice. About 1850, Earth's climate began to gradually warm ending the Little Ice Age; this warming lasted until about 1940. Beginning in 1940, temperatures leveled off and began to drop slightly once again.
Another fact to keep in mind is that the most pronounced increase in temperature in the 20th century occurred before 1940, when human production of greenhouse gases was at a much lower level than it is today. The climate actually cooled somewhat between 1940-1980, although the amount of greenhouse gases produced by man increased. This fact casts doubt on the relationship of man's production of greenhouse gases and the global climate.
Finally, man's contribution of CO2 and other green house gases is considerably less than nature's. Man contributes about 7 billion tons of carbon dioxide to the atmosphere per year, compared to nature's own contribution of 200 billion tons.
