This video continues our discussion of “Livestock and Climate Change,” by Robert Goodland and Jeff Anhang. Goodland and Anhang make five points in their article, and this video explains point 3: undercounted methane.
Compassionate Spirit
Simple living and veganism in a world of limits
Speaking of methane, a friend wrote to me and pointed out this study:
“How much do direct livestock emissions actually contribute to global warming?” By Andy Reisinger and Harry Clark. Global Change Biology, Volume 24, Issue 4, April 2018, p. 1749-1761.
The gist of the article is to underscore Goodland and Anhang’s concern over methane. The abstract starts out by saying that “Agriculture directly contributes about 10%–12%” of all emissions but then says that the actual warming is much higher than that. Livestock methane is estimated to cause 19% of ALL warming! Yet Goodland and Anhang seem to estimate the total CO2e of methane emissions (counted + uncounted) is only about 12% of all emissions. So Reisinger and Clark seem to think that the actual warming percentage of methane is greater even than Goodland and Anhang’s estimate.
The abstract says (the original article is behind a paywall): “We find that direct livestock non-CO2 emissions caused about 19% of the total modelled warming of 0.81°C from all anthropogenic sources in 2010. CO2 from pasture conversions contributed at least another 0.03°C, bringing the warming directly attributable to livestock to 23% of the total warming in 2010.” . . . “These estimates constitute a lower bound [emphasis added] since indirect emissions linked to livestock feed production and supply chains were not included.”
Clarification: In the original video, I posted a graphic that quoted Climatewire as saying that “the choice of GWP100 is simply a matter of convention.” Climatewire’s statement is a bit misleading. It makes the choice of time frame sound more arbitrary or controversial than it actually is. I have revised this video and removed this statement from the graphic. It would be more correct to say that the choice of which time frame to choose it is a question of “policy” and to quote the IPCC in support (p. 229).
The IPCC (on p. 229) immediately adds: “If the policy emphasis is to help guard against the possible occurrence of potentially abrupt, non-linear climate responses in the relatively near future, then a choice of a 20-year time horizon would yield an index that is relevant to making such decisions regarding appropriate greenhouse gas abatement strategies.”