Lukewarm response from scientists to US-China climate change deal

Don't expect the landmark US-China climate change agreement to nudge the world's rising thermostat downward much on its own, scientists say.

While they hail it as a start, experts who study heat-trapping carbon dioxide don't see the deal, announced on Wednesday in Beijing, making significant progress without other countries joining in. The maths shows that even with the agreement, the globe is still rushing toward another 2 degrees Celsius temperature rise - a level that world leaders have pledged to avoid as too dangerous.

China, the world's No1 polluter, will still increase its emissions until 2030 or so, under the agreement. The US, which ranks second, promised to cut pollution from the burning of coal, oil and gas to levels that haven't been seen since 1969. But whatever cuts the US makes will be swamped by the Chinese growth in pollution over the next 15 years.

"It doesn't change things much," said Glen Peters, a Norwegian scientist who was part of the Global Carbon Project, an international team of researchers that tracks and calculates global emissions every year. "This is not far off the business as usual" scenario the world is already on, he said.

In 2009, countries across the globe set a goal of limiting global warming to about 1 degree above current levels. Peters' team has calculated that the world would hit that mark around 2040 and the US-China accord doesn't change that, he said. The numbers are just too big, especially out of China.

Professor John Sterman, of the Massachusetts Institute Technology, who runs computer simulations of global emissions, compared the numbers to a driver with his foot all the way down on the accelerator in the fog heading toward a cliff. While this agreement helps, it's only letting up on the pedal, not slowing the car.