La surveillance des émissions anthropiques de CO2 depuis l’espace : un enjeu géopolitique émergent
Abstract
The Paris climate agreement in 2015, and more generally policies to combat climate change, are based on knowledge of greenhouse gas emissions, in particular carbon dioxide (CO2) emissions, from human activity, established by inventories combining data on these activities and corresponding emission coefficients. This approach currently presents limitations, with varying levels of uncertainty depending on the countries and sectors of activity, and in terms of latency and spatial and temporal resolution, which penalize the transparency and reliability sought by the Paris agreement. However, the acquisition and processing of observations, particularly satellite observations, of atmospheric CO2 concentrations could enable rapid and reliable estimates of CO2 emissions at different spatial scales, and the evaluation or even the improvement of the quality of inventories. This article thus shows that this atmospheric approach, long limited to scientific research, is now emerging as a means of responding to the political need for new capacities for monitoring CO2 emissions. Europe has great ambitions in this area, with the Copernicus Anthropogenic Carbon Dioxide Monitoring (CO2M) space mission and the preparation of an operational service for atmospheric monitoring of anthropogenic CO2 emissions, which would feed into official declarations of European emissions. However, the current maturity of the processing chains does not yet make it possible to qualify such a system. Using its CO2 emissions estimates in an international framework poses many technical and policy challenges, which this article discusses, giving them general context and perspective. To do this, it relies on a review of scientific articles and of reports for political decision-makers, and on knowledge of international exchanges on the subject.
