Standard ratios

Standard ratios are used to convert the various greenhouse gases into equivalent amounts of CO2. These ratios are based on the so-called global warming potential (GWP) of each gas, which describes its total warming impact relative to CO2 over a set period – usually 100 years. Over this time frame, methane scores 25 (meaning that one tonne of methane will cause the same amount of warming as 25 tonnes of CO2), nitrous oxide comes in at 298 and some of the super-potent fluorinated gases score more than 10,000.