U.S. global warming satellite seeks missing carbon

SAN FRANCISCO, Jan 29 (Reuters) - The United States will launch a satellite next month to measure carbon dioxide in the atmosphere and to determine what happens to the climate-changing pollutant, NASA said on Thursday.

Carbon dioxide is the main cause of global warming. Burning fossil fuels and deforestation has raised carbon dioxide concentrations to levels that are causing global alarm about a changing climate. Measurement of the gas outside Europe and the United States is spotty, NASA researchers said.

After vehicles and factories release carbon dioxide into the air, the world's oceans and land absorb much of it. But scientists cannot figure out where the remaining carbon dioxide goes, a detail critical to forecasting the speed and reach of pollution's effect on climate.

"While we understand approximately how much carbon dioxide is released into the atmosphere each year due to human influences, we can only account for about half of the carbon dioxide that doesn't remain in the atmosphere," Eric Ianson, National Aeronautics and Space Administration program director for the Orbiting Carbon Observatory, told a news conference.

The $278 million program launches its satellite on Feb. 23. For two years, the satellite will cover all of the Earth every 16 days. During each 16-day cycle, the satellite will take 8 million measurements of carbon dioxide.

Japan this month launched a satellite to measure carbon dioxide and methane, another greenhouse gas. [ID:nT440] Both launches come as about 190 nations try to agree on a successor climate change treaty to the Kyoto Protocol, which binds wealthy nations -- not including the United States -- to emissions targets through 2012.

NASA said the Japanese and U.S. satellites use different technology, fly in different orbits, and have slightly different missions. The Japanese satellite is focused on monitoring sources of carbon dioxide for treaties, while the U.S. effort focuses on what happens to the gas.

The U.S. technology measures light bounced off the planet. Carbon dioxide absorbs light in some frequencies, so the less light detected, the higher the concentration of carbon.

In certain areas around the world, plants and the ocean remove carbon dioxide from the air. NASA wants to know why, how and where these natural areas, known as "carbon sinks," exist, mission scientist Anna Michalak said at the news conference.

"The reason we want to know this is we want to be able to better predict how these sinks or these outtakes will evolve in the future," Michalak said.

Reporting by Peter Henderson