CO2 measurements

CO2 measurements over the Northern Hemisphere obtained at the Earth’s surface (thin lines) from Envisat’s SCIAMACHY instrument (thick yellow line and two northern hemispheric maps). This figure highlights the natural fluxes of CO2 which, unlike manmade CO2 fluxes, operate in both directions – taking up atmospheric CO2 during spring and summer when plants grow, but releasing most or all of it again later in the year, when the plants decay. This results in higher atmospheric CO2 concentrations in the first half of a year followed by lower CO2 during the second half of a year with a minimum around August.