NASA eyes Carbon-dioxide..

A NASA satellite being prepared for launch early on Tuesday is expected to reveal details about where carbon dioxide, a greenhouse gas tied to climate change, is being released into Earth's atmosphere on a global scale.

The two-year, $465 million project, known as the Orbiting Carbon Observatory, or OCO, also will be able to pinpoint where the planet's forests and ocean are re-absorbing atmospheric carbon, a cycle that is key to Earth's temperature.





More than 50 years of measurements show that about half the amount of carbon dioxide put into the atmosphere - by natural processes and human activities - end up being reabsorbed. The proportion has remained fairly constant even as the total amount of atmospheric carbon has climbed from concentrations of 315 parts per million in the 1950s to 400 parts per million today, studies by the US National Oceanic and Atmospheric Administration and the Scripps Institution of Oceanography show.

The observatory will be positioned 438 miles (705 km) above the planet and inclined so that it passes over the same point on Earth at the same time every 16 days, giving scientists insight into how levels of carbon dioxide change over weeks, months and years. Because the observatory's target areas will be small - about 1 square mile (3 square km) - scientists expect to be able to pinpoint top carbon emitters, though monitoring is not among the mission's goals.