Though, the "25 times" takes the limited lifetime into account. The short term effect is much more. For example the so called "20 year global warming potential"

Though, the "25 times" takes the limited lifetime into account. The short term effect is much more. For example the so called "20 year global warming potential" is 72, compared to CO2's 1. More here: http://en.wikipedia.org/wiki/Global-warming_potential http://en.wikipedia.org/wiki/Global-warming_potential