Researchers Measure Global Carbon Dioxide Levels

Using data generated by planes that traveled between the North and South Poles, Harvard researchers generated the first set of highly detailed measurements of greenhouse gas levels across the globe. This comprehensive data set is now available to the public.

The researchers were part of the HIAPER Pole-to-Pole Observations team, comprised of scientists from Harvard University, University of Miami, Princeton University, the National Center for Atmospheric Research, the National Oceanic and Atmospheric Administration, Scripps Research Institute, and Scripps Institution of Oceanography.

“We were filling in some important new pieces of information about what controls the climate system,” said atmospheric and environmental studies professor and lead principle investigator Steven C. Wofsy.

He said that, while satellites have long gathered data on carbon dioxide and other trace atmospheric gases, distance prevented them from measuring at a more refined level.

The HIPPO project utilized manned flights to investigate the seasonal factors which have a significant effect on the distribution of greenhouse gases in the atmosphere, said team member Gregory Santoni, a graduate student in the department of earth and planetary sciences.

Data collection took place between 2009 and 2011 in five missions, each comprised of roughly 10 to 12 flights and each of which lasted three-week flights.

The flights traveled across the Pacific Basin, maneuvering through different altitudes to obtain data from a large cross section of the atmosphere.

In all, the team obtained 785 vertical profiles and 4,000 flask samples from the atmosphere in over 600 hours of flight.

The data set contains a number of new insights regarding atmospheric gas concentration. For instance, researchers found evidence that Southeast Asia is a vigorous source of the greenhouse gas nitrous oxide, a fact that was previously unnoticed. According to Santoni, the data set also suggests that current models used to predict the removal of black carbon—a substance considered to significantly contribute to global warming—are inaccurate.

Additionally, researchers found evidence that, as human activity has caused the ice cover over the Arctic Ocean to recede, significant amounts of methane are being produced by previously submerged biological processes occurring on the ocean’s surface.

“You wouldn’t necessarily think of human impact as being something that has a chain of events,” Wofsky said.

The team is hopeful that the data set can be applied to research involving climatological issues in a number of different fields.

—Staff writer Alyza Sebenius can be reached at asebenius@college.harvard.edu. Follow her on Twitter @asebenius.

This article has been revised to reflect the following correction:

CORRECTION: April 9, 2013

An earlier version of this article incorrectly stated the number of flask samples that a team of Harvard researchers obtained from the atmosphere. In fact, they collected 4,000 samples, not 400. The story also incorrectly stated that they collected these and other measurements in under 600 hours of airplane flight, while in fact they obtained their data in over 600 hours of flight.

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