Climate cycle

A climate cycle is a natural variation in the earth's surface temperature, as indicated by temperature proxies found in glacier ice and sea bed sediment.

1,500-year climate cycle

• Human activities have little to do with the Earth's current warming trend, according to a study published by the National Center for Policy Analysis (NCPA). In fact, S. Fred Singer (University of Virginia) and Dennis Avery (Hudson Institute) conclude that global warming and cooling seem to be part of a 1,500-year cycle of moderate temperature swings.
• Scientists got the first unequivocal evidence of a continuing moderate natural climate cycle in the 1980s, when Willi Dansgaard of Denmark and Hans Oeschger of Switzerland first saw two mile-long ice cores from Greenland representing 250,000 years of Earth's frozen, layered climate history. From their initial examination, Dansgaard and Oeschger estimated the smaller temperature cycles at 2,550 years. Subsequent research shortened the estimated length of the cycles to 1,500 years (plus or minus 500 years).
• Independent data in a seabed sediment core from the Atlantic Ocean west of Ireland, reported in 1997, showed nine of the 1,500-year cycles in the last 12,000 years. [1]

Climate cycles and global warming

There is considerable scientific disagreement over how much influence these cycles have had (or will have) on the period of global warming which weather stations have recorded since around 1880 (see Scientific opinion on climate change and global warming controversy).

See also

• Dansgaard-Oeschger events
• ice age
• El Niño
• North Atlantic oscillation
• Milankovich cycles - Periodic variations in earth’s orbit

External links

• The physical evidence of earth's unstoppable 1,500-year climate cycle - National Center for Policy Analysis

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