Livestock Methane Emissions: An Opportunity to Slow Global Warming?
The world is experiencing unprecedented extreme weather events due to climate change, caused by accumulation of greenhouse gases (GHG). Methane is a GHG with global warming potential of 28 times that of carbon dioxide over a 100-year period and much more effective in trapping heat during the time it is in the atmosphere. The largest source of methane is from agriculture and waste and particularly ruminants such as cattle. Globally, livestock are responsible for about 14.5% of GHG emissions. According to the Food and Agriculture Organization of the United Nations (FAO), demand for animal products is increasing and resulted more than 50% increase in emissions over the last 60 years.
Enteric methane represents more than 4% of annual global GHG emissions and contributes to 70% of GHG emissions from livestock in the US. Therefore, it is key to mitigating such emissions. A number of strategies have been developed to reduce enteric methane emissions. The mitigation strategies can be classified into (1) feed manipulation, (2) rumen modifiers, and (3) increasing animal production through genetics and management. One of the most effective ways to reduce methane is using seaweed (Aspragopsis) that has over 80% effectiveness. Recent research at UC Davis consistently showed that this technology not only reduces emission but also improves feed efficiency, which is important if it is going to be adopted by farmers world-wide. The race is on to produce the seaweed in a sustainable manner and make it available to hundreds of millions of cattle and mitigate their emissions. Just over 0.3% annual reduction of methane is expected to slow down or even reverse global warming in the short term giving us time to deploy CO2 reducing technologies and switch to carbon neutral economies.
Ermias Kebreab is Associate Dean of Global Engagement and Director of World Food Center at University of California, Davis. He holds the Sesnon Endowed Chair in Sustainable Agriculture. He conducts research in animal nutrition, mathematical modeling of biological systems and impact of livestock on the environment. He is contributing author to 2019 IPCC update on enteric methane emissions. He co-chaired the feed additive and methane committees of the Food and Agriculture Organization of the United Nations. He has authored over 250 peer-reviewed articles and received several awards including Excellence in Ruminant Nutrition and International Agriculture from American Society of Animal Science. He served on two committees of The National Academies of Sciences, Engineering and Medicine on methane and nutrition of dairy cattle. He is regularly an invited speaker including TED and TEDx talks. His research was in the top 10 of all research conducted at the University of California system in 2021. He holds a B.S. degree from the University of Asmara, Eritrea and an M.S. and Ph.D. from the University of Reading, U.K.
Watch recorded lecture below.