Three minutes of stupidity: Al Gore unveils his "single most powerful bit of evidence about how the Earth is warming"--the fact that after a carefully chosen cool base period of 1951-1980, the Earth warmed

Finale with Al Gore | Climate Reality

At the 12:00 mark, Gore says "This is in my opinion the single most powerful bit of evidence about how the Earth is warming. There is no climate science involved."

Gore says "I wish I had a better command of it [statistics] honestly."

Global cooling - Wikipedia, the free encyclopedia

In the 1970s, there was increasing awareness that estimates of global temperatures showed cooling since 1945.

Time Mag Flashback: 1974 Issue Warns of Man-Made 'Global Cooling' | NewsBusters.org

From the Jun 24, 1974, Time Magazine, entitled: "Another Ice Age?"

As they review the bizarre and unpredictable weather pattern of the past several years, a growing number of scientists are beginning to suspect that many seemingly contradictory meteorological fluctuations are actually part of a global climatic upheaval. However widely the weather varies from place to place and time to time, when meteorologists take an average of temperatures around the globe they find that the atmosphere has been growing gradually cooler for the past three decades. The trend shows no indication of reversing. Climatological Cassandras are becoming increasingly apprehensive, for the weather aberrations they are studying may be the harbinger of another ice age.

Telltale signs are everywhere —from the unexpected persistence and thickness of pack ice in the waters around Iceland to the southward migration of a warmth-loving creature like the armadillo from the Midwest.Since the 1940s the mean global temperature has dropped about 2.7° F. Although that figure is at best an estimate, it is supported by other convincing data. When Climatologist George J. Kukla of Columbia University's Lamont-Doherty Geological Observatory and his wife Helena analyzed satellite weather data for the Northern Hemisphere, they found that the area of the ice and snow cover had suddenly increased by 12% in 1971 and the increase has persisted ever since. Areas of Baffin Island in the Canadian Arctic, for example, were once totally free of any snow in summer; now they are covered year round.