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Research Affirms Gases’ Effects Studies: Greenhouse Substances Causing Warming of Oceans

By Eric Pianin
THE WASHINGTON POST -- Two new studies released Thursday provide the strongest evidence yet that greenhouse gases are causing the Earth’s oceans to warm, further strengthening the case that global warming is real and is being caused at least in part by air pollution, researchers said.

Previous research had shown that the Atlantic, Pacific and Indian oceans -- covering 72 percent of the Earth’s surface -- have collectively warmed, on average, about one-tenth of a degree Fahrenheit since 1955. But whether that was caused by global warming has been far from clear.

The new studies, based on parallel computer climate models, show a direct connection between rising ocean temperatures and emissions of carbon dioxide and other gases that can trap heat within the atmosphere. The models showed that the warming of the ocean that has been measured over the last half-century is exactly what would be expected from the amount of greenhouse gases that have been emitted into the atmosphere.

“I believe our results represent the strongest evidence to date that the Earth’s climate system is responding to human-induced forcing,” said Sydney Levitus of the Commerce Department’s National Oceanographic Data Center, lead author of one of the studies.

“This will make it much harder for naysayers to dismiss predictions from climate models,” added Tim Barnett of the Scripps Institution of Oceanography. He is the lead author of the other study, funded by the National Science Foundation.

The two studies, published in Thursday’s issue of the journal Science, come amid an ongoing international debate prompted by President Bush’s recent decision to abandon the global warming treaty negotiated in 1997 in Kyoto, Japan.

Although administration officials have repeatedly described global warming as a real and serious problem, Bush contends the treaty is unfair because it would seriously damage the U.S. economy if implemented and because it exempts China, India and developing countries from the tough strictures on industrial emissions.

Bush has ordered a Cabinet-level panel to draft proposals for combating global warming. They will be presented to U.S. allies later this summer. But his unilateral decision to pull out of the treaty has infuriated European, Japanese and Canadian leaders who fear Bush may have torpedoed an international negotiation process that has spanned the better part of a decade.

Underscoring the issue’s sensitivity, government scientists involved in the new global warming studies have been cautioned by a Commerce Department spokesperson to “stick with the science rather than delve into policy” in discussing their findings with reporters.

The two studies add to the wealth of recent data on global warming, which, scientists say may be causing changes in weather patterns and shrinking glaciers and permafrost. That, they added, could eventually touch off catastrophic climate changes.

A United Nations panel of scientists concluded earlier this year that the Earth’s temperature could rise by as much as 10.4 degrees over the next 100 years -- the most rapid change in 10 millennia and more than 60 percent higher than what the group predicted less than six years ago.

William Patzert, a scientist with the NASA Jet Propulsion Laboratory in Pasadena, Calif., cautioned that although there’s no doubt the oceans are warming, “there is a lot of natural variability in the oceans.”

“The trick is to extract the small warming or sea-level rise over the last 50 years and relate that directly to the greenhouse emissions, which have been significant,” he added.