NASA Satellite To Track Carbon Dioxide Globally
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NASA, the space agency, plans to launch a research satellite tomorrow. It's designed to answer some of the most puzzling questions about global warming. It is called the Orbiting Carbon Observatory, or OCO. And in that word carbon, you get a sense of its mission. It's a gold mechanism, weighs about a thousand pounds, sports a pair of blue solar panels, and it's designed to help scientists understand how carbon dioxide flows into and out of our atmosphere.
NPR's Richard Harris reports.
RICHARD HARRIS: We all know carbon dioxide is building up rapidly in the atmosphere, and scientists generally have a pretty good idea about where it's coming from - tailpipes, chimneys, smokestacks, burning forests. But there's something not even scientists fully understand.
Dr. DAVID CRISP (NASA's Jet Propulsion Laboratory): One of the big mysteries is that almost 60 percent of the carbon dioxide we've been emitting into the atmosphere since the beginning of the industrial age has been disappearing somewhere.
HARRIS: David Crisp at NASA's Jet Propulsion Laboratory is the lead scientist on a space mission to track down all that carbon. Scientists figure that a lot of the carbon goes into the ocean, and they think most of the rest is gobbled up by terrestrial plants. They figured that out using just a handful of monitoring stations scattered around the globe.
Crisp says, as you can imagine, a handful doesn't give you a very sharp picture. That's why he wants the bird's-eye view from space.
Dr. CRISP: And so, instead of making a few hundred measurements every month from the surface of the Earth, we're planning to make about seven million measurements from space every two weeks.
HARRIS: The OCO satellite will circle the globe more than a dozen times a day, and it will complement the data from a similar Japanese satellite that has just started its operations. It'll measure infrared light bouncing off the Earth. From that, scientists can calculate carbon dioxide concentrations across the entire globe.
When they see slightly higher levels of carbon dioxide, they know they are looking at sources of the gas. When they see slightly lower levels, that's where some carbon dioxide must be leaving the air.
Dr. CRISP: We don't understand the processes that are absorbing over 60 percent of the CO2 that we're putting out today. We don't know whether those processes will continue into the future, actually become more efficient or actually maybe become much less efficient as time goes on and as the climate changes. Because of that, we can't accurately predict how much CO2 will be in our atmosphere, say, 50 years from now.
HARRIS: And since carbon dioxide is the single-most important greenhouse gas, that makes it harder to predict the speed and intensity of climate change. Of course, another big unknown is how well we do in our own efforts to cut back on carbon dioxide emissions. Countries have made various promises to cut back, and it would be great to be able to monitor that from space. But Crisp says OCO won't be able to police international agreements.
Dr. CRISP: You probably wouldn't want to rely on a science experiment to tell you whether or not some country is complying with some treaty that it signed.
HARRIS: For one thing, OCO's results are only reliable over a fairly wide area, something like the size of Colorado.
Steven Wofsy at Harvard University says that's because carbon dioxide quickly disperses in the atmosphere and literally blows around the world.
Dr. STEVEN WOFSY (Harvard University): There's no way to look at a measurement, let's say, in central United States and determine how the variations that you see are caused by what farmers are doing right underneath where you're making the observations, what's happening in Washington State or in China or Russia.
HARRIS: But Wofsy says you can build up a detailed picture of emissions from any given point on Earth if you not only look at the satellite measurements, but add in ones taken from the ground and others that he takes from periodic airplane flights.
So in the not-too-distant future, we could have a better picture of how carbon dioxide enters and ultimately exits our atmosphere.
Richard Harris, NPR News.