Readings from NASA’s Orbiting Carbon Observatory-2 have confirmed that the El Niño weather pattern of 2015-2016 was behind the biggest annual increase in atmospheric carbon dioxide levels in millennia.
The OCO-2 satellite, launched in 2014, is designed to provide a detailed picture of how carbon is exchanged between air, land and sea.
OCO-2 data showed that 2015’s El Niño weather, created by warmer waters in the central and eastern Pacific Ocean, led to hotter conditions in tropical regions of South America, Africa and Indonesia.
In South America, drought stressed out vegetation so much that less carbon dioxide was converted through photosynthesis into oxygen, researchers reported today in the journal Science.
In Africa, hotter-than-normal temperatures led to faster decomposition of dead trees and plants, releasing more carbon into the atmosphere. And in Indonesia, dry conditions led to increased fires, which also released more carbon.
“These three tropical regions released 2.5 gigatons more carbon into the atmosphere than they did in 2011,” lead study author Junjie Liu of NASA’s Jet Propulsion Laboratory said in a news release.
The findings suggest that, at least in some cases, higher levels of atmospheric carbon dioxide result from the interplay of natural conditions and human activity.
“Understanding how the carbon cycle in these regions responded to El Niño will enable scientists to improve carbon cycle models, which should lead to improved predictions of how our planet may respond to similar conditions in the future,” said JPL’s Annmarie Eldering, deputy project scientist for the OCO-2 mission. “The team’s findings imply that if future climate brings more or longer droughts, as the last El Niño did, more carbon dioxide may remain in the atmosphere, leading to a tendency to further warm Earth.”
Liu and Eldering are among 16 authors of the Science study, “Contrasting Carbon Cycle Responses of the Tropical Continents to the 2015-2016 El Niño.” The study is one of several research papers in Science reporting results from the OCO-2 mission.