A figure shows the whole-atmospheric CO2 concentrations monitored by GOSAT, which measured more than 400 ppm for the first time in the satellite's history. (Credit: JAXA)
A recent analysis of data from the Greenhouse gases Observing SATellite IBUKI (GOSAT) shows that the global atmospheric monthly mean CO2 concentration observed vertically through the whole atmosphere exceeded 400 ppm in December 2015 for the first time since GOSAT was launched in 2009 by the Ministry of the Environment, Japan; National Institute for Environmental Studies; and Japan Aerospace Exploration Agency (JAXA).
Several meteorological agencies have reported data at surface-level monitoring sites that exceeded 400 ppm, but this is the first time the whole-atmospheric CO2 mean exceeded 400 ppm monitored by GOSAT, which can observe CO2 concentrations from the surface to the top of the atmosphere (about 70 kilometers). It means that CO2 concentrations are increasing not only at the global surface but also in the global atmosphere.
