We hear a lot about humanity's "carbon footprint" in the news. Some politicians and activists appear to like the term, but many use it without a complete understanding of the genuine technical issues behind its coining. Thus, the term can spark some some pretty heated exchanges on talk shows and even at town meetings right here in Vermont.
Be that as it may, by the time you read this column-if all goes well-NASA's Orbiting Carbon Observatory (OCO) will have been launched from Vandenberg Air Force Base in California (the launch was set for Feb. 24). This unusual space mission will help scientists, back on Earth, better predict changes in our weather and climate; it will also improve our understanding about how natural hazards affect weather and long-term climate.
While OCO probably won't settle the public debate regarding climate change, it will go a long way in helping scientists gain more precise measurements of carbon dioxide (CO2) in our atmosphere.
OCO data should also improve our understanding of both natural processes and human activities that produce so-called greenhouse gases-who knows, we may learn definitively (within a year or two) whether fossil-fuel burning is causing climate change as many now claim.
NASA's Jet Propulsion Laboratory is leading the OCO effort. The lab's expertise in spacecraft design and manufacture has made OCO one of the most sophisticated environmental satellites launched to date.
"OCO will be making one of the most challenging measurements of any atmospheric trace gas that has ever been made," said Charles Miller, OCO deputy principle investigator at JPL in Pasadena Calif.
Hamilton Sundstrand Sensor Systems of Pomona, Calif., provided a high-tech instrument that will measure carbon dioxide and oxygen molecules in the Earth's atmosphere; this instrument will study how the molecules of the two gases absorb sunlight.
With future data in hand, researchers should then be able to see where, and how, natural and man-made sources add carbon dioxide to the atmosphere.
"The enormous challenges inherent in the mission are due to the small variations in the amounts of atmospheric carbon dioxide. Those levels range from a maximum of 362 carbon dioxide molecules in 1 million molecules of air, to a minimum of 351 carbon dioxide molecules in 1 million air molecules - a 0.3 percent difference," said David Crisp, principle investigator for the OCO at JPL.
Right now, the Carbon Dioxide Information Analysis Center of the U. S. Department of Energy tracks and monitors CO2 emissions as part of a worldwide network of ground-based stations. Unfortunately, the DOE network can't "see" the a part of the distribution of CO2 sources, at least on the continent-size scale; so getting into outer space and looking down on the Earth will provide better measurements.
"These measurements will be combined with data from the ground-based network to provide us with the information that we will need to better understand the processes that regulate atmospheric CO2 and its role in the carbon cycle. This enhanced understanding is essential to improve predictions of future atmospheric CO2 increases and their impact on the climate. This information could help policy makers and business leaders make better decisions to ensure climate stability and, at the same time, retain our quality of life," said Crisp.
Lou Varricchio, M.Sc., is a former NASA science writer. He is currently part of the NASA/JPL Solar System Ambassador program team in Vermont.