Methane and its global warming potential
This article in the New Scientist entitled 'Methane controls before risky geoengineering, please' by Prof. Kirk Smith, makes the following points:
This article in the New Scientist entitled 'Methane controls before risky geoengineering, please' by Prof. Kirk Smith, makes the following points: 'Methane is a much more powerful greenhouse gas than CO2. A tonne of methane is responsible for nearly 100 times more warming over the first five years of its lifetime in the atmosphere than a tonne of CO2. Methane is removed from the atmosphere much more rapidly than CO2, with a half-life of 8.5 years compared with many decades for CO2, but a tonne of methane eventually turns to 2.75 extra tonnes of CO2 in the atmosphere. Even without taking this into consideration, a tonne of methane emitted today will exert more annual warming than a tonne of CO2 emitted today until 2075. Not until the year 7300 will the cumulative warming exerted by the two become equal.' The article criticises the conventional IPCC weighting system that gives a tonne of methane a global warming potential 21 times that of CO2 over a 100-year period, given the short time scale we face. It points out that this weighting gives equal importance to measures that will reduce warming in 2109 and warming next year. You can read the article here.