Of the various long-lived greenhouse gases (LLGHG), the atmospheric concentration of carbon dioxide
alone is responsible for approximately 84% of the increase in the radiative forcing observed over
the past decade and deemed to be at the root of the heating phenomenon (WMO, 2014). Fig. 1 shows
a very simplified global carbon cycle, with four sinks represented: atmosphere, terrestrial biosphere,
oceans and lithosphere. For each sink, the current estimated carbon storage and the current flows with
the other sinks are reported..