Ocean Warming Studies Bolster Evidence of Human Hand in Climate Change.

• Author: Runyan, Curtis
• Position: Update

Two new independent studies on the warming of the Earth's oceans add some of the most convincing evidence yet that human actions are playing a significant role in the Earth's rising temperatures. The studies, published in the April, 13 2001 issue of Science, compared different computer projections of climate change with new records showing the Earth's oceans have warmed 0.06 degrees C (0.11 degrees F) in the past 40 years, and found the computer simulations and the actual rate of ocean warming closely match up.

"Our results support climate modeling predictions that show increasing atmospheric greenhouse gases will have a relatively large warming influence on the earth's atmosphere," said the lead author of one study, Sydney Levitus of the U.S. National Oceanic and Atmospheric Administration. Until now, oceans have been a sort of missing link in our understanding about climate change. Computer models have predicted more warming of the atmosphere than has actually occurred, leading scientists to speculate that the "missing warming" is being absorbed by the oceans. The new studies strongly support this explanation.

"What we found is that the signal is so bold and big that you don't have to do any fancy statistics to beat it out of the data," said the lead author of the second study, Tim Barnett of the Scripps Institute of Oceanography in California. "It's just there, bang." Barnett said that the warming in his model so closely matched the rates and location of the actual warming that the "results are certainly compatible at the 95 percent confidence level with the hypothesis that the warming observed in the global oceans has been caused by [human] sources."

The research bolsters the growing body of research finding that human activities have been the dominant influence in the recent rise of the Earth's global temperature, including a new report by the Intergovernmental Panel on Climate Change (IPCC), a group of more than 100 of the world's top climate scientists. The IPCC report projects the Earth's average temperature will increase by 1.4 to 5.8 degrees C by 2100 (see "Climate change report released," March/April 2001).

The ocean temperature increase of 0.06 degrees C may seem small, but spread throughout the oceans, which cover more than...