Solving Earth’s Mysteries

Earth recently experienced its largest annual increases in atmospheric carbon dioxide levels in at least 2,000 years. Data from NASA’s Orbiting Carbon Observatory-2 (OCO-2), which launched in 2014, are helping scientists understand why.

Many factors go into improving long-term climate forecasting, including the study of how, how much, and where carbon dioxide (CO₂) is absorbed and emitted by natural processes and human activities at different locations on Earth’s surface. These exchanges vary from year to year, and scientists are using OCO-2 data to uncover the reasons.

Dr. Annmarie Eldering, Deputy Project Scientist for OCO-2 at NASA’s Jet Propulsion Laboratory explains: “We already knew that the global amount of carbon dioxide taken up and released by the land and ocean differs each year, and that often in El Niño years, more CO₂ remains in the atmosphere. But this mission’s high-precision data on atmospheric CO₂ across the globe have shown us, for the first time, how different regions contributed to this phenomenon and exactly what was driving the change.”

OCO-2 data for an El Niño event during 2015-2016 revealed that extra CO₂ in the atmosphere at that time was caused by releases from South America, Africa, and Indonesia.

Eldering says, “We saw that each of these regions released more carbon for slightly different reasons -- different combinations of increased temperatures, less rain, or more fires.”

Not all of the carbon dioxide emitted into Earth’s atmosphere stays there. Some of the CO₂ is absorbed by Earth’s oceans. Natural land sinks also absorb CO₂, but the amounts of CO₂ taken up at different locations on Earth’s surface are not well understood.

Eldering asks: “As carbon dioxide continues to build up, will the land and ocean continue absorbing it? Will natural processes reach a saturation point or will they keep taking up more and more?”

The many and varied uses of OCO-2 data will continue to be essential to understanding the dynamics of carbon dioxide across our planet, and will help contribute to improved long-term climate forecasting.

For more intriguing discoveries about our changing planet, stay tuned to science.nasa.gov.