Now that another Earth Day has come and gone, let's look at some environmentalist predictions that they would prefer we forget.

At the first Earth Day celebration, in 1969, environmentalist Nigel Calder warned, "The threat of a new ice age must now stand alongside nuclear war as a likely source of wholesale death and misery for mankind." C.C. Wallen of the World Meteorological Organization said, "The cooling since 1940 has been large enough and consistent enough that it will not soon be reversed." In 1968, Professor Paul Ehrlich, Vice President Gore's hero and mentor, predicted there would be a major food shortage in the U.S. and "in the 1970s ... hundreds of millions of people are going to starve to death." Ehrlich forecasted that 65 million Americans would die of starvation between 1980 and 1989, and by 1999 the U.S. population would have declined to 22.6 million. Ehrlich's predictions about England were gloomier: "If I were a gambler, I would take even money that England will not exist in the year 2000."

In 1972, a report was written for the Club of Rome warning the world would run out of gold by 1981, mercury and silver by 1985, tin by 1987 and petroleum, copper, lead and natural gas by 1992. Gordon Taylor, in his 1970 book "The Doomsday Book," said Americans were using 50 percent of the world's resources and "by 2000 they [Americans] will, if permitted, be using all of them." In 1975, the Environmental Fund took out full-page ads warning, "The World as we know it will likely be ruined by the year 2000."

Harvard University biologist George Wald in 1970 warned, "... civilization will end within 15 or 30 years unless immediate action is taken against problems facing mankind." That was the same year that Sen. Gaylord Nelson warned, in Look Magazine, that by 1995 "... somewhere between 75 and 85 percent of all the species of living animals will be extinct."

It's not just latter-day doomsayers who have been wrong; doomsayers have always been wrong. In 1885, the U.S. Geological Survey announced there was "little or no chance" of oil being discovered in California, and a few years later they said the same about Kansas and Texas. In 1939, the U.S. Department of the Interior said American oil supplies would last only another 13 years. In 1949, the Secretary of the Interior said the end of U.S. oil supplies was in sight. Having learned nothing from its earlier erroneous claims, in 1974 the U.S. Geological Survey advised us that the U.S. had only a 10-year supply of natural gas. The fact of the matter, according to the American Gas Association, there's a 1,000 to 2,500 year supply.

Here are my questions: In 1970, when environmentalists were making predictions of manmade global cooling and the threat of an ice age and millions of Americans starving to death, what kind of government policy should we have undertaken to prevent such a calamity? When Ehrlich predicted that England would not exist in the year 2000, what steps should the British Parliament have taken in 1970 to prevent such a dire outcome? In 1939, when the U.S. Department of the Interior warned that we only had oil supplies for another 13 years, what actions should President Roosevelt have taken? Finally, what makes us think that environmental alarmism is any more correct now that they have switched their tune to manmade global warming?

Here are a few facts: Over 95 percent of the greenhouse effect is the result of water vapor in Earth's atmosphere. Without the greenhouse effect, Earth's average temperature would be zero degrees Fahrenheit. Most climate change is a result of the orbital eccentricities of Earth and variations in the sun's output. On top of that, natural wetlands produce more greenhouse gas contributions annually than all human sources combined.