Scientist says CO2 not main cause of warming

Published February 1, 2001

A leading Canadian researcher recently published a study in the British science journal Nature that found carbon dioxide (CO2) is not the prime cause of global warming. The study was authored by Jan Veizer, a geologist selected by the Canadian government to examine CO2.

In the article, Veizer asserts that other natural factors, such as fluctuations in the intensity of the sun, are most likely the main cause of global warming incidents during the Earth’s history. Many scientists said Veizer’s findings pose a “serious challenge to some basic assumptions in climate change.”

The five-year, $700,000 study tracked global temperatures and greenhouse gas emissions back 500 million years. Veizer identified long periods in the Earth’s history when high levels of CO2 were accompanied by a drop in average temperature.

“Sure we have a greenhouse effect, but it’s much more complex than just carbon dioxide,” said Veizer.

Veizer said international officials should still continue efforts to reduce global CO2 emissions, but should not hold the hope that limiting CO2 emissions will end global warming. Veizer believes CO2 and greenhouse gas (GHG) emissions most likely amplify climate change trends triggered by another factor.

Reprinted from the December 7, 2000 issue of the Toronto Star.