Offsetting methane emissions - An alternative to emission equivalence metrics

Title
Offsetting methane emissions - An alternative to emission equivalence metrics
Publication Date
2013
Author(s)
Lauder, A R
Enting, I G
Carter, J O
Clisby, N
Cowie, Annette
Henry, B K
Raupach, M R
Type of document
Journal Article
Language
en
Entity Type
Publication
Publisher
Elsevier Ltd
Place of publication
United Kingdom
DOI
10.1016/j.ijggc.2012.11.028
UNE publication id
une:13318
Abstract
It is widely recognised that defining trade-offs between greenhouse gas emissions using 'emission equivalence' based on global warming potentials (GWPs) referenced to carbon dioxide produces anomalous results when applied to methane. The short atmospheric lifetime of methane, compared to the timescales of CO₂ uptake, leads to the greenhouse warming depending strongly on the temporal pattern of emission substitution. We argue that a more appropriate way to consider the relationship between the warming effects of methane and carbon dioxide is to define a 'mixed metric' that compares ongoing methane emissions (or reductions) to one-off emissions (or reductions) of carbon dioxide. Quantifying this approach, we propose that a one-off sequestration of 1 t of carbon would offset an ongoing methane emission in the range 0.90-1.05 kg CH₄ per year. We present an example of how our approach would apply to rangeland cattle production, and consider the broader context of mitigation of climate change, noting the reverse trade-off would raise significant challenges in managing the risk of non-compliance. Our analysis is consistent with other approaches to addressing the criticisms of GWP-based emission equivalence, but provides a simpler and more robust approach while still achieving close equivalence of climate mitigation outcomes ranging over decadal to multi-century timescales.
Link
Citation
International Journal of Greenhouse Gas Control, v.12, p. 419-429
ISSN
1878-0148
1750-5836
Start page
419
End page
429

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