NASA Releases New Map of Human-Made Carbon Dioxide Emissions

A team of scientists has released the first satellite-based global maps of human carbon dioxide (CO2) emissions.

The maps are based on data from NASA's Orbiting Carbon Observatory 2 (OCO-2) satellite, which are generated with a new data-processing technique and are in line with known carbon dioxide emission inventories, NASA said.

While earlier maps incorporate estimates from economic data and modeling results to gather more information, OCO-2 is capable of measuring carbon dioxide emissions in fine enough detail to allow scientists to create maps of human-caused emissions using satellite data alone.

"OCO-2 can even detect smaller, isolated emitting areas like individual cities," Jane Hakkarainen, a research scientist at the Finnish Meteorological Institute in Helsinki, Finland who led the study, said in a statement. "It's a very powerful tool that gives new insight."

The group created three main maps from OCO-2 data, each focusing on one of Earth's highest-emitting regions: the eastern United States, central Europe, and East Asia.

Carbon dioxide emissions remain in the atmosphere for 100 years and more, which means that recent human output is only a small portion of the total carbon dioxide that OCO-2 records. In 2015, carbon dioxide levels have already surged past the climate change benchmark for the first time.

"Currently, the background level of carbon dioxide in the atmosphere is about 400 parts per million, and human emissions within the past year may add only something like three parts per million to that total," Hakkarainen said, adding that the data-processing challenge was isolating the signature of the recent emissions from the total amount.

The researchers developed a new data-processing technique that accounts seasonal changes in carbon dioxide, the result of plant growth and dormancy, and background carbon dioxide level. The results were compared with nitrogen dioxide measurements from the Ozone Monitoring Instrument (OMI) - a Dutch-Finnish instrument on NASA's Aura satellite that covers the same area of the Earth as OCO-2.

The researchers found that the two measurements correlated well, which means the technique produced reliable results.

"The research demonstrates the possibility of analyzing joint satellite observations of carbon dioxide and other gases related to combustion processes to draw out information about the emissions sources," Johanna Tamminen, co-author of the study, said in the same statement.

The results of the study were published Nov. 1 in the journal Geophysical Research Letters.