Carbon dioxide plays a vital role in our planet’s life, bearing responsibility for the greenhouse effect that makes the Earth temperate and habitable. Of course, it’s possible to have too much of a good thing, in which case CO2 becomes a very bad thing. Excess carbon dioxide produced by humans is indeed starting to affect the Earth's climate, though ambiguities remain. And so NASA is poised to launch its Orbiting Carbon Observatory-2, or OCO-2, a new spacecraft that will create a global picture of the effects of this excess carbon on our atmosphere.The Earth deals with atmospheric carbon dioxide naturally through “sinks”—locations where the gas is pulled from the atmosphere and trapped in oceans and in land. At the moment, less than half of the human-produced carbon dioxide emitted into the atmosphere stays there. Most is absorbed back into the planet. But just where these natural sinks are isn’t well understood, and the excess gas we’re producing coupled with increased deforestation is adding more carbon dioxide into the atmosphere than the Earth can regulate on its own.
Exactly how the Earth, through its own clever mechanisms, is handling the increased levels of carbon dioxide is what the OCO-2 mission is investigating. The spacecraft will collect the data scientists need to provide a more complete global map of Earth's CO2 .The OCO-2 spacecraft’s science payload features three high-resolution spectrometers. Each is optimized to record a specific color absorbed by carbon dioxide and oxygen molecules in the Earth’s atmosphere, and together the three are designed to break reflected sunlight into its component colors to precisely measure the intensity of each. On the whole, less atmospheric carbon dioxide translates to more light detected by the spectrometers. The light absorbed by the spectrometers will then allow scientists to estimate the relative concentrations of atmospheric gases.The science team behind the OCO-2 mission hopes this detailed investigation will reveal the location and properties of these natural sinks and how they pull natural and human-produced carbon dioxide out of the atmosphere. "With the OCO-2 mission, NASA will be contributing an important new source of global observations to the scientific challenge of better understanding our Earth and its future,” said Michael Freilich, director of NASA's Earth Science Division."Knowing what parts of Earth are helping remove carbon from our atmosphere will help us understand whether they will keep doing so in the future," said Michael Gunson, an OCO-2 project scientist at NASA's Jet Propulsion Laboratory. "Understanding the processes controlling carbon dioxide in our atmosphere will help us predict how fast it will build up in the future. Data from this mission will help scientists reduce uncertainties in forecasts of how much carbon dioxide will be in the atmosphere and improve the accuracy of global climate change predictions.”The mission is slated to launch on a United Launch Alliance Delta II rocket on July 1. It will end up in a 438-mile near-polar orbit, becoming the lead in a group of Earth-monitoring satellites that orbit the Earth at a rate of one every 99 minutes. This new data will be added to existing observations scientists have been gathering since 2009 using Japan’s GOSAT satellite as well as data gathered by ground stations, aircraft, and other satellites. Hopefully we’ll learn not only how Earth is handling excess carbon dioxide, but how we can stop the situation from getting worse, maybe with help from the planet itself.