No doubt you’ve heard that raising cattle (for beef or any other purpose) contributes to global warming because the critters have the nasty habit of emitting methane by belching and—well, what they do from the other end.
A new paper by our friends Will Happer and W.A. van Wyngaarden at the CO2 Coalition quantifies global methane emissions’ warming effect and finds it negligible.
Each methane atom has about 30 times the heat (infrared) absorption capacity of each molecule of CO2, causing many people to think it’s a potentially far greater contributor to global warming. But we emit about 300 times as much CO2 as methane, meaning methane’s total heat absorption effect is only about a tenth of CO2’s.
They calculate the combined warming effect of our global methane and CO2 emissions at 0.012 degree C per year. Methane’s is about a tenth of that, 0.0012 degree C per year (0.12 per century). CO2’s is the other nine tenths, 0.0108 degree C per year (1.08 per century).
Those amounts of warming aren’t significantly dangerous—and, the authors point out:
Given the huge benefits of more CO2 to agriculture, to forestry, and to primary photosynthetic productivity in general, more CO2 is almost certainly benefitting the world. And radiative effects of CH4 and N2O, another greenhouse gas produced by human activities, are so small that they are irrelevant to climate.
So go ahead, eat your beef (or for that matter any other livestock that produces methane).
Featured image by adapted from a photo by Marino Bobetic on Unsplash.
