Towards real-time verification of CO_2 emissions

摘要

Emissions of CO_2 from fossil fuels and industry did not change from 2014 to 2016, yet there was á record increase in CO_2 concentration in the atmosphere. This apparent inconsistency is explained by the response of the natural carbon cycle to the 2015-2016 El Nino event, but it raises important questions about bur ability to detect a sustained change in emissions from the atmospheric record. High-accuracy calibrated atmospheric measurements, diverse satellite data, and integrative modelling approaches could, and ultimately must, provide independent evidence of the effectiveness of collective action to address climate change. This verification will only be possible if we can fully filter out the background variability in atmospheric CO_2 concentrations driven by natural processes, a challenge that still escapes us.