AR5_SYR_Figure_1.3.png

But carbon dioxide is not the only greenhouse gas whose concentration has increased.

As shown in this figure created by the IPCC (Intergovernmental Panel on Climate Change), the concentration of methane (produced in particular by rice paddies and cattle farming) and nitrous oxide (mainly produced by fertilizers) is also on the rise.

As these gases occupy only a very small percentage of atmospheric volume, their concentrations are measured in parts per million "ppm" (number of molecules per million atmospheric molecules) and parts per billion "ppb".

[Source : rapport du GIEC (2013), The physical science basis]