Carbon Market Science Updates Add Value to Digester Projects

Sheldon Zakreski, The Climate Trust
Weekly Policy and Finance Update – May 29, 2018

THE BOTTOM LINE.

For all too long, the carbon market has relied on science from 1995 to compare the equivalencies of greenhouse gases – under-crediting projects that reduce potent but short-lived climate pollutants like methane. Emissions of greenhouse gases other than carbon dioxide are converted to carbon dioxide “equivalents” by applying a global warming potential. Carbon offset protocols have relied upon the global warming potential values produced by the Intergovernmental Panel on Climate Change’s Second Assessment Report from 1995. Under this old science, methane is considered 21 times more potent than carbon dioxide over a 100-year time period. The more recent value published in the IPCC’s Fifth Assessment Report, for comparison, is 34. Simply by using old science, livestock anaerobic digester projects have only been receiving 62% of the offset credits they should be generating.

Luckily, carbon markets are evolving. For compliance offset projects, starting in 2021, the global warming potential for methane will be updated to 25 (the value from the 2007 Fourth Assessment Report). And in May, the Climate Action Reserve also determined all voluntary projects going through new verification will also use this updated value from the Fourth Assessment Report. Livestock projects should therefore be expecting a 20% boost in the value of their greenhouse gas reduction simply by this intermediate update to the science behind the protocol.

Old global warming potential values are yet another example of the conservative calculations behind offset projects. And remember, all these global warming potentials compare the warming caused by different greenhouse gases over a 100-year period. As the effects of climate change are increasingly felt and action is demanded, there is a focus on “short lived climate pollutants” and scientists and policy makers, including the Air Resources Board, are beginning to look at 20-year global warming potentials as well – where methane is 84 times as potent as carbon dioxide. The IPCC writes, “there is no scientific argument for selecting 100 years compared with other choices,” and California is intelligently beginning to question this paradigm. It’s becoming clearer and clearer that mitigating potent greenhouse gas emissions is an essential first step; the offset mechanism is clearly an efficient way of targeting these gases. Let’s use the latest science to ensure projects are properly incented.

Research and Resources

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Image credit: Flickr/Mark Jensen