NASA to track Carbon Emissions of each country using data from orbiting observatory

Researchers have tracked carbon dioxide emissions of more than 100 nations worldwide with the aid of a NASA Earth-observing satellite. The pilot research provides a compelling new look at the amount of carbon dioxide emitted in these nations and how much of it is absorbed by forests and other "sinks" of carbon within their borders. The results show how space-based tools might help with Earth-related insights as countries try to meet climate goals.

The international study, carried out by more than 60 researchers, quantified rises and declines in atmospheric carbon dioxide concentrations from 2015 to 2020 using data from NASA's Orbiting Carbon Observatory-2 (OCO-2) spacecraft and a network of surface-based observations. The researchers were thus able to determine the balance of how much carbon dioxide was emitted and removed using this measurement-based (or "top-down") method.

Despite the fact that the OCO-2 mission was not explicitly created to estimate emissions from specific countries, the results from the more than 100 countries are timely. In accordance with the terms of the 2015 Paris Agreement, the first Global Stocktake, which evaluates worldwide progress towards limiting global warming, will take place in 2023.

“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,” said Karen St. Germain, director of NASA’s Earth Science Division at NASA Headquarters in Washington. She further said, "This is one example of how NASA is developing and enhancing efforts to measure carbon emissions in a way that meets user needs.”

Tracking Carbon

Calculating and estimating the amount of carbon dioxide being released across all economic sectors, such as transportation and agriculture, is the foundation of traditional activity-based (or "bottom-up") approaches to carbon assessment. Bottom-up carbon inventories are essential for gauging the success of emission-reduction initiatives, but creating them takes a large investment in time, talent, and understanding of the scope of the pertinent activities.

According to the study's authors, building a database of emissions and removals through a top-down strategy could be especially beneficial for governments without conventional resources for inventory development. In reality, data from more than 50 nations that haven't recorded emissions in at least ten years are included in the scientists' results.

By monitoring both fossil fuel emissions and changes in the global "stock" of carbon in ecosystems, such as trees, shrubs, and soil, the study offers a fresh viewpoint. The information is especially helpful for detecting variations in carbon dioxide levels associated with shifting land cover. The Global South, which includes parts of Latin America, Asia, Africa, and Oceania, produces an excessive amount of carbon emissions alone from deforestation. The results point to some reductions in atmospheric carbon concentrations through better land stewardship and reforestation in other parts of the planet.

According to the authors, it is crucial to use bottom-up techniques for calculating ecosystem carbon dioxide emissions and removals. Yet, when data is scarce or the overall consequences of particular activities, like logging, aren't well understood, those methods are susceptible to uncertainty.

“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,” said Philippe Ciais, a study author and research director at the Laboratoire des Sciences du Climat et de l’Environnement in France.

The study provides a detailed picture of how carbon is transported through the land, oceans, and atmosphere of Earth. Unmanaged ecosystems like some tropical and boreal forests, where humans have a small impact, can trap carbon from the atmosphere, preventing potential global warming, in addition to the direct human impacts taken into consideration by national inventories.

“National inventories are intended to track how management policies impact emissions and removals of CO2,” said study author Noel Cressie, a professor at the University of Wollongong in Australia. “However, the atmosphere doesn’t care whether CO2 is being emitted from deforestation in the Amazon or wildfires in the Canadian Arctic. Both processes will increase the concentration of atmospheric CO2 and drive climate change. Therefore, it is critical to monitor the carbon balance of unmanaged ecosystems and identify any changes in carbon uptake.”

The researchers claimed their pilot experiment can be improved in the future to learn more about how emissions from various countries are altering. 

“Sustained, high-quality observations are critical for these top-down estimates,” said lead author Brendan Byrne, a scientist at NASA’s Jet Propulsion Laboratory in Southern California. “Continued observations from OCO-2 and surface sites will allow us to track how these emissions and removals change as the Paris Agreement is implemented. Future international missions that provide expanded mapping of CO2 concentrations across the globe will allow us to refine these top-down estimates and give more precise estimates of countries’ emissions and removals.”

The 2014-launched OCO-2 satellite uses three spectrometers that resemble cameras to map the amounts of both naturally occurring and artificially produced carbon dioxide. These tools are calibrated to pick up the distinct carbon dioxide spectrum, or light signature. They gauge the gas indirectly by observing how much reflected light a specific air column absorbs.