Signatory nations to the Paris Agreement, which targets a mean global temperature increase of up to 1.5° C, report annual greenhouse gas emissions data to the UN. The conventionally applied bottom-up approach to delineating the global carbon budget compares these emissions trends with estimates of the amount of carbon absorbed by natural sinks.

The European Space Agency (ESA) augments these analyses with a top-down approach based on measurements from space. In addition to monitoring atmospheric carbon, ESA’s Climate Change Initiative uses satellite observations to track other carbon stocks on land and sea. The resulting data are combined with atmospheric and biophysical computer models to deduce carbon fluxes at the surface in an effort to Image from the Copernicus Sentinel-2 mission. Source: ESAimprove the precision of each greenhouse gas budget and help separate natural fluxes from agricultural and fossil fuel emissions.

Researchers in China have also started to collect satellite data on global greenhouse gas emissions. Measurements made by the Chinese Global Carbon Dioxide Monitoring Scientific Experimental Satellite (TanSat) from May 2017 to April 2018 indicate that about six gigatons of carbon appear to be emitted over land every year.

The data published in Advances in Atmospheric Sciences were used to prepare the first global carbon flux dataset and map depicting how greenhouse gases are exchanged among Earth's atmosphere, land, water and living organisms. Such data can be used to independently verify national emission inventories.