As Oceans Get Warmer, Congress Is Facing Heat

by David Perlman, Chronicle Science Editor

http://www.sfgate.com/cgi-bin/article.cgi?f=/c/a/2010/05/19/MNPS1DGRNN.DTL

On the same day that climate researchers reported strong new evidence that the temperatures of the world's oceans are on the rise, teams of America's leading scientists Wednesday called on Congress to face the urgent problem of global warming by raising the cost of greenhouse gas emissions to U.S. industry.

View of the Sindipumba Glaciar in Ecuador. The academy scientists warned that "business as usual" is no longer possible for American industry and called on Congress to quickly enact a "carbon pricing system" to curb the rise in greenhouse gas emissions. (AFP/File/Jorge Vinueza)

The reality of the planet's changing climate was underscored by a new report on ocean temperatures that combined years of conflicting data into what researchers say is a realistic picture of ocean warming and the National Academy of Sciences, which released three major reports on the science behind the climate problem and the urgency with which it must be faced.

There is no longer any doubt that global warming is real, said Pamela A. Matson, dean of the School of Earth Sciences at Stanford, who led one of five panels organized at Congress' request to assess the reality and urgency of global warming and propose measures to cope with it.

"Climate change is occurring," Matson said. "The Earth is warming, concentrations of carbon dioxide are increasing, and there are clear fingerprints that link these warming effects to human activity."

End business as usual

The three academy reports issued Wednesday totaled more than 860 pages and represent a dramatic shift from the organization's cautious approach to climate change in the past. The academy scientists warned that "business as usual" is no longer possible for American industry and called on Congress to quickly enact a "carbon pricing system" to curb the rise in greenhouse gas emissions.

In 2008, American industries emitted the equivalent of 7 billion tons of carbon dioxide, the academy experts noted. They suggested that the nation adopt a "greenhouse budget" of permitted carbon emissions that would range from 170 billion to 200 billion tons of carbon dioxide for the period from 2012 to 2050, saying it is a "reasonable goal." If greenhouse gas emissions continue at the 2008 level, the scientists warned, the budget would be exceeded well before 2050.

"We focused primarily on carbon dioxide because it is responsible for so much of the problem," said Robert W. Fri, an energy expert and academy member from the nonprofit, nonpartisan Resources for the Future.

To reach even part of the goal recommended by the academy, either a "cap-and-trade" system or a tax on carbon emissions or a combination of both are needed, the scientists said.

They gave a special nod to the cap-and-trade concept. That system would set limits on how much carbon-containing gases could be emitted by industries as a whole, and then allow companies that emit little or none of the gases to sell "carbon credits" to the big polluters.

The issue of cap-and-trade is a thorny political one; the Obama administration supports such a system and Congress is wrestling with it. The House passed a bill last year, but it stalled in the Senate, which deferred it while the health care bill was debated.

Rising sea levels

In a separate report published today, but released Wednesday, in the journal Nature, scientists from the United States, Britain, Germany and Japan said they have found "robust" evidence that sea levels have risen over the past 16 years as the upper layers of the world's oceans have warmed and caused water expansion. They looked to the ocean for signals of climate change because the oceans absorb up to 90 percent of the heat that reaches Earth from the sun.

The oceans have warmed by at least three-tenths of a degree Fahrenheit since 1993, and where sea levels were rising by only 1 millimeter a year 100 years ago, the rate is now 3 millimeters a year, said John Lyman, an oceanographer with the National Oceanographic and Atmospheric Administration. The effects may seem small, but they are highly significant, he said.

The scientists in the Nature study deployed a global network of more than 3,200 free-floating sensors across all the oceans, and the sensors broadcast their readings on temperature, salinity and currents to satellites overhead.

More accuracy

The results, they said, are far more accurate than earlier ocean studies, which resulted in a wide range of estimates because temperatures were recorded by ships towing instruments called XBTs - for expendable bathythermographs - and they covered only part of the world.

"If you want to know how the world has warmed, you've got to look at the upper layers of the ocean," Lyman said. "And it continues to warm."