Specieswatch: Wild deer release millions of tonnes of methane a year
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- Theresia Yazbeck and colleagues at the Max Planck Institute for Biogeochemistry in Jena, Germany, calculated that wild ruminants release around 3 million tonnes of methane per year.
- Six species of deer account for more than half of all wild ruminant methane emissions, making deer the single largest wild contributor.
- Published in the Journal of Geophysical Research: Biogeosciences, the study combined global wild animal population estimates with methane emission rates based on body mass and diet.
- Wild ruminant methane output is approximately 38 times smaller than emissions from domesticated livestock.
- Total global methane emissions exceed 600 million tonnes annually, putting wild ruminants at a small but persistent fraction of the total.
- Like cows, deer, moose, and llamas rely on gut bacteria to break down fibrous plants, releasing methane as a byproduct of digestion.
Why it matters: Methane is a potent greenhouse gas climbing rapidly, but the study confirms that policymakers targeting emissions can safely focus on domesticated livestock—responsible for 38 times more methane than all wild ruminants combined. Wild deer, despite topping the wild-ruminant list at over half the total, are a rounding error in a global methane budget exceeding 600 million tonnes per year.
