Satellite measurements of greenhouse gases in the atmosphere can be used to track changes in carbon sources and sinks. This top-down approach can help countries improve checks and consistency of their national greenhouse gas inventories so that they more accurately reflect global emissions.

ESA’s Regional Carbon Cycle Analysis and Processes project has developed new methodologies that combine satellite and in situ observations and biophysical computer models to deduce carbon fluxes at Earth’s surface. Significant discrepancies between this approach and the corresponding national reports were found.

Methane emissions were found to be higher using the inversion method when compared to most national reports; more carbon dioxide was absorbed by managed forest and agricultural land, while observed increases in emissions from natural ecosystems were not reflected in national reporting.

If regularly applied, this new approach will not only improve transparency in the accounting process, but will also improve the effectiveness of mitigation policy and progress by individual countries to meet their pledges as part of the Paris Agreement.