June 20, 2019
CO2, the gas that has the greatest global warming effect, is used as a benchmark, and we compute a “global warming potential” (GWP) for other greenhouse gases for a given period of time that represents its greenhouse effect.
This unit is calculated on a horizon based on a 100-year period, to take into account the time spent in the atmosphere by each GHG. For example, the GWP for one ton of methane is 28 times higher than one ton of CO2 over a 100-year scale. Thus, each ton of methane is equivalent to 28 tons of CO2 in the GHG emission balances.
The six greenhouse gases covered by the Kyoto Protocol (CO2, methane, nitrous oxide, and three fluorinated gases) amounted to 54 Gt eq CO2 in 2013 (over 100 years). The IPCC suggests that a reduction in these emissions by at least 40% by 2050 (compared to the 2010 level) and a nearly "carbon-neutral" economy during the second half of the 21st century would help us limit global warming and help us stay under the 2°C goal from the COP21 agreement.