NASA Satellite Records Big Increase in Carbon Dioxide
by Ryan Whitwam
NASA’s Orbiting Carbon Observatory (OCO-2) is tasked with scanning the globe to track greenhouse gas emissions, and it recently delivered some troubling news. A dramatic spike in carbon dioxide was detected, and it could be a sign that tropical forest regions are not able to keep absorbing such a large volume of carbon from the atmosphere.
The OCO-2 is one of several carbon-tracking satellites managed by NASA’s Jet Propulsion Laboratory (JPL) in California. NASA researcher Junjie Liu used the advanced spectrographic tools on OCO-2 to determine how carbon levels are changing over time. The OCO is equipped with three high-resolution spectrometers capable of extremely accurate readings of carbon dioxide and molecular oxygen. However, it’s only able to take readings of a narrow 6.2 mile (10 kilometers) swath of Earth under the satellite.
The newly processed data comes from 2015 and 2016, which are important years for climate scientists. These were El Niño years, which are defined by a band of unusually warm water around the equator. This disrupts regular weather patterns, and the 2015 and 2016 El Niño was the most severe in decades.
Under normal circumstances, the concentration of carbon dioxide goes up by two parts per million by volume (ppmv) of air molecules. That works out to four gigatons of added carbon dioxide in the atmosphere. However, the OCO-2 detected a 3 ppmv jump in the recent El Niño years. Climate researchers estimate it’s been around 2,000 years since the Earth has seen such a large increase.
It’s tempting to just chalk this one up to humans burning more fossil fuels, but all the data indicates out activity was unchanged during that period–we certainly didn’t increase our output by 50 percent. The OCO-2 data indicates carbon dioxide sinks like the rainforests were not absorbing as much as they do during other years. In South America, drought slowed plant growth and thus carbon absorption. Warmer weather in Africa accelerated plant decomposition, adding to atmospheric carbon. In Asia, dry conditions and fires also reduced the amount of carbon absorbed by plants.
The team warns that if El Niño frequency increases, so too will greenhouse gas levels. Without carbon sinks working at maximum efficiency, we’ll get ourselves into trouble even faster than predicted. It is hoped that Europe’s upcoming Sentinel-7 carbon dioxide mapping satellites will help scientists study this process in more detail. They could even make it possible to track the carbon output from individual countries to determine who’s doing their part to tackle climate change.
Originally published at www.extremetech.com on October 16, 2017.