Savanna projects currently receive carbon credits according to UN approved global warming potentials for methane and nitrous oxide.
But are projects being shortchanged?
The global warming potentials are based on relative heating of greenhouse gases compared to carbon dioxide over 100 years. The current potentials for methane and nitrous oxide are 25 and 298 (recently updated).
However, a paper by Shindell et al., “Improved Attribution of Climate Forcing to Emissions“, (Science 30 October 2009), and reported on the excellent Food Climate Research Network, argues that methane is more potent than the UN potentials suggest. This is due to the interaction of methane with soot in the atmosphere. The paper gives the more generous potential of 33 over a hundred year period.
Lining up for more credits?
There’s more. There is also debate about whether the reference period ought to be 100 years or something shorter to reflect that, while carbon dioxide is stable and longlived in the atmosphere, other greenhouse gases break down fairly quickly – in methane’s case, usually within about 10 years.
Given this, some argue that 20 years would be a better reference period. The paper calculates a methane potential on this basis would be 105 – four times the current value of 25.
Now given the conservative nature of methodologies under the CFI, when you collect your credit cheque you can be really sure you are having a positive impact on our natural environment. Even if not fully rewarded.