Besides carbon dioxide there are various types of gas which contribute to the greenhouse effect and have different effects on global warming depending on their heat absorbing capacity. These include:
 

• Methane gas (CH4) has a global warming potential about 25 times greater than carbon dioxide over a 100-year period;
   

• Nitrous oxide (N2O) has a global warming potential about 300 times that of carbon dioxide over a 100-year period.

 

Global Warming Potential (GWP) is used to measure (in CO2e) the climate impact of each greenhouse gas, expressing how long it is capable of trapping heat in the atmosphere compared with carbon dioxide over a specific period of time (radiative forcing).

 

Let’s take for example methane (CH4) which has a GWP of about 25 over 100 years. This means that during this period, methane gas has a global warming potential 25 times that of CO2 per unit of mass emitted. Thus, if we want to assess the overall climate impact of an activity that emits both methane and CO2, we can convert the methane emissions into "CO2 equivalent" by multiplying the amount of the methane emissions by its GWP.

 

The GWP of greenhouse gases are periodically published and updated by the IPCC.