Carbon dioxide is the villain in global warming scenarios, and Tuesday's space launch is all about measuring carbon around the world to see how well it's behaving — or misbehaving.

The Orbiting Carbon Observatory launches into space from Vandenburg Air Force Base in California on Tuesday, armed with a computer program designed by Colorado State University researchers.

The mission essentially "tracks the Earth's breathing," said Scott Denning atmospheric science professor at CSU.

It employs a spectrograph, a handy scientific tool that can identify elements as they drift through light, forming a prism-like bar code of what's out there.

CSU's algorithm works with the spectrograph to detect the ratio of oxygen to carbon in different spots around the world. Because oxygen exists almost perfectly uniformly everywhere on the planet, the varying ratios can pinpoint where there is extra carbon or an absence of it.

Healthy forests and cool oceans "breathe in" carbon by the ton, including about half of the carbon emitted by coal plants, automobiles and other icons of the modern age.

That's hugely important because the carbon that isn't absorbed by plants and oceans gets into the atmosphere where it acts as a barrier, preventing sunlight from bouncing back into the upper atmosphere, hence warming the planet.

But decaying forests lose the capacity to absorb carbon, as do forests that have been razed for farming or development.

Planet-wide, "plants are growing faster than they are dying, which is remarkable," Denning said.

The big question is how long that will last, how long will the Earth's own living system keep some $400 billion worth of carbon from getting stuck in the atmosphere each year.

The satellite will orbit pole to pole about every 90 minutes, and by shifting its crossings slightly everyday, will get a good even coverage of the globe and its carbon, said David Baker, a postdoctoral fellow at CSU.

It's a great improvement from the system that employs 100 people around the planet to grab a jar full of air each day and ship it to a lab for testing.

The OCO satellite data could influence policy down the road.

In a few years, the satellite data can state with certainty that, say, the melting permafrost in Canada and Siberia is sending much bigger amounts of carbon into the atmosphere than it did 20 years ago, Baker said. "That could give more impetus to control global warming."

Or, the data could find that the Amazonian rain forest is doing a yeoman's task of absorbing fossil fuels from millions of cars, fireplaces and coal plants.

"That finding would make it all the more important not to cut down the forests," Baker said.

The satellite data also could quantify the plumes of carbon rising above major cities.

The OCO instrument will measure sunlight that passes through the atmosphere twice — once on the way down to the surface, and again after it bounces off the Earth and gets back into the atmosphere, said Randy Pollock, a systems engineer for NASA's Jet Propulsion Laboratory, which is working with CSU on the project.

The spectrograph splits the gas molecules into bar codes, letting scientists calculate how many molecules of carbon dioxide the sunlight saw as it passed through the atmosphere.

The instrument will find "sources," which are places that are losing their ability to absorb carbon — deforested farmland, warmer seas, areas devastated by forest fires or pine beetles.

And the instrument will find "sinks," spots on the globe that absorb immense amounts of carbon dioxide, keeping it from causing trouble — healthy forests, icy stretches of polar oceans.

Many scientists worry that the carbon sinks will lose their capacity to take up carbon in the coming years.

"We have to understand how the sinks work so we can anticipate when the climate might start changing much faster than it's already changing," Denning said. "OCO is going to let us do that."

scanlon@RockyMountainNews.com or 303-954-2897