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Pandemic lockdowns reduced greenhouse gas levels in some areas, satellite views show

This NASA supercomputer model shows how greenhouse gases like carbon dioxide fluctuate in Earth’s atmosphere throughout the year. Higher concentrations are shown in red.
This NASA supercomputer model shows how greenhouse gases like carbon dioxide fluctuate in Earth’s atmosphere throughout the year. Higher concentrations are shown in red. (Image credit: NASA’s Scientific Visualization Studio / NASA’s Global Modeling and Assimilation Office)

Satellite data shows small but highly specific decreases in atmospheric carbon dioxide due to pandemic-related lockdowns, a new study shows.

While climate scientists warn the temporary lockdowns were not nearly enough to make a dent in the growing threat of global climate change, satellite tech did show drops of 0.14 to 0.62 parts per million in specific zones between February and May 2020. (Most jurisdictions entered some form of lockdown that March.)

The measurements were a welcome sign to scientists that satellites are up to the task of monitoring atmospheric carbon dioxide levels, which are notoriously difficult to measure. Since carbon dioxide is a key greenhouse gas, though, monitoring its levels in the atmosphere accurately will be key to adjusting our response to global warming, study authors say.

Related: Dropped emissions during COVID-19 lockdown will do 'nothing' for climate change  

"Current space-based technologies are approaching levels of accuracy and precision needed to support international climate mitigation strategies, signaling progress toward a long-sought goal," the team said in a statement released on Wednesday (Nov. 3). 

"Atmospheric carbon dioxide is difficult to monitor because it forms a major, well-mixed and globally distributed component of the atmosphere," the statement continued. "In contrast, nitrogen dioxide, for example, appears in distinct, concentrated plumes directly above emissions sources."

The team developed a new model using data from the NASA Goddard Space Flight Center's Earth Observing System (GEOS). This is an agency Earth science model that monitors levels of global atmospheric carbon dioxide every three hours, using "statistically processed data" from the Orbiting Carbon Observatory-2 (OCO-2) satellite that launched in 2014.

At launch time, OCO-2 was advertised as being able to measure carbon dioxide levels in the atmosphere up to 24 times a second, which would allow scientists to see where the gas originated and where it is removed from the air (more officially known as "sources" and "sinks.")

The study team paid tribute to the help of OCO-2 in helping to develop their model. "This strategy has improved coverage, accuracy, and precision over existing techniques, accounts for year-to-year carbon dioxide variability that results from shifts in atmospheric circulation, and produces regular updates in near real time," the team said in their statement.

A paper based on the research was published in Science Advances, led by Brad Weir, a research scientist at NASA Goddard Space Flight Center and Universities Space Research Association. 

The research was released during the United Nations Climate Change Conference (COP26) in Glasgow, which ends Nov. 12. During the conference Tuesday (Nov. 2), Europe pledged to build a new satellite constellation to track human-made greenhouse gas emissions, including carbon dioxide.

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Elizabeth Howell

Elizabeth Howell is a contributing writer for Space.com who is one of the few Canadian journalists to report regularly on space exploration. She is the author or co-author of several books on space exploration. Elizabeth holds a Ph.D. from the University of North Dakota in Space Studies, and an M.Sc. from the same department. She also holds a bachelor of journalism degree from Carleton University in Canada, where she began her space-writing career in 2004. Besides writing, Elizabeth teaches communications at the university and community college level, and for government training schools. To see her latest projects, follow Elizabeth on Twitter at @howellspace.