2. Global warming

2.1 Greenhouse gases

International awareness of the risks posed by global warming due to greenhouse gas (GHG) emissions dates back some thirty years. Given the scale of the transformations required, the measures needed to limit these risks are only gradually being put in place.

The carbon dioxide emitted when fossil fuels are burned acts as a greenhouse gas, according to the mechanism shown in figure 3 , by reflecting back to earth part of the infrared radiation reflected at the ground surface. The resulting additional heat flux, expressed in W/m ² , is referred to as radiative forcing....