The research comes at a key time for nations seeking to calculate their emissions and plan their reductions. PHOTO/UGC
By PATRICK MAYOYO
Until recently, the question about which countries emit the most net carbon dioxide was answered by calculating the emissions of each sector in a nation’s economy via a “bottom up” approach.
However, a new paper published in Earth System Science Data March 7 pilots a “top down” approach by using NASA satellite data to calculate how much carbon dioxide more than 100 nations emit, and how much their natural carbon sinks suck back up again.
“Our top-down estimates provide an independent estimate of these emissions and removals, so although they cannot replace the detailed process understanding of traditional bottom-up methods, we can check both approaches for consistency,” study co-author and Laboratoire des Sciences du Climat et de l’Environnement in France research director Philippe Ciais said in a NASA press release.
The paper, which was the work of more than 60 scholars from around the world, used carbon dioxide data from NASA’s Orbiting Carbon Observatory-2 (OCO-2) mission as well as ground level data. It covered the years between 2015 and 2020.
The satellite data revealed that the top emitting countries were, as The Weather Channel reported:
- The U.S.
The commonly used “bottom up” method of carbon accounting is extremely useful but also demands expertise and accurate data, making it harder for nations with fewer resources. The “top down” method can therefore fill in the gaps, providing data for more than 50 countries that had not reported their emissions in the past decade.
Other high emitters were the UK, the rest of the western EU, Australia, Kazakhstan, much of North Africa, South Africa, Chile, Thailand and the Philippines. In the Global South, deforestation was a major driver of emissions, according to NASA.
EcoWatch says overall, the findings are similar to other lists of top emitting countries, with China, the U.S. and India leading the way in Climate Watch’s data set. However, Russia, Canada and Saudi Arabia were on the top 10 according to Climate Watch but not according to the satellite data, with Canada and Russia emerging as net carbon dioxide sponges. This is likely because national emissions data typically only includes greenhouse gas emissions and removals from managed land, while the satellite data accounts for unmanaged land as well, the study authors noted.
The research comes at a key time for nations seeking to calculate their emissions and plan their reductions. That’s because 2023 marks the first global stocktake, in which signatories of the Paris agreement must evaluate their progress towards limiting global warming to well below two degrees Celsius above pre-industrial levels. The study is one example of how data from space can help improve life on Earth.
“NASA is focused on delivering Earth science data that addresses real-world climate challenges – like helping governments around the world measure the impact of their carbon mitigation efforts,” NASA’s Earth Science Division at NASA Headquarters in Washington Director Karen St. Germain said in the press release. “This is one example of how NASA is developing and enhancing efforts to measure carbon emissions in a way that meets user needs.”