NCPA - National Center for Policy Analysis


March 1, 2005

Global warming disasters may be much ado about nothing. In fact, a team of American climatologists concludes that man-made greenhouse gases may have averted a potential ice age, according to new research.

Scientists traditionally attribute the Earth's climate stability over the past 10,000 years to natural causes. But the climate team's research, published in Quaternary Science Reviews, shows that human intervention may have played a part:

  • Changes in solar radiation and greenhouse gas concentrations should have moved the earth towards glacial conditions over the last few thousand years.
  • However, ancient and modern human activity have produced higher levels of carbon dioxide during the past 8,000 years, delaying the onset of another ice age.
  • Researchers attribute many pre-industrial activities to the increase of greenhouse gas, such as early deforestation in Eurasia, rice farming in Asia, the introduction of livestock, and the burning of wood and plant material.

The team, led by William Ruddiman from the University of Virginia in Charlottesville, modeled what might happen if greenhouse gases remained at their natural levels. They found:

  • Global temperatures would be cooler by 2 degrees Celsius than they are today.
  • The Earth would be about one-third of the way toward full glacial temperatures.

Source: Rhiannon Edward, "Man-made Greenhouse Gases Saved World From Big Freeze," Scotsman, January 24, 2005; and William Ruddiman, et al., "A Test of the Overdue-glaciation Hypothesis," Quaternary Science Reviews, vol. 24, no. 1, January 2005.


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