Methane has 23X the impact of carbon dioxide on warming and livestock produces methane - burping cows burp.

But it is a tiny fraction of climate change impact unless you are in the activism business, and then livestock accounts for 12 percent of human-related greenhouse gas emissions, using incredibly false metrics like "it takes a gallon of gas to grow a pound of beef" and adding in estimates based on land use change and deforestation. A much lesser amount comes from manure management and feed production. To activists, driving to the store is better for the environment than walking, if you eat meat.

The people who are against meat and invent false metrics for environmental impact sure are not embracing genetically modified cows that will burp less, but perhaps optimizing livestock diets will escape their notice - and it could also improve food security.

You don't have to give up meat, no matter what groups selling environmental brochures claim. Optimized diets for livestock could cut greenhouse gas emissions by as much as 23 percent by 2030. Credit: International Livestock Research Institute (ILRI)

International Institute for Applied Systems Analysis
researcher Petr Havlík, who led the PNAS study, “but our results show that targeting the production side of agriculture is a much more efficient way to reduce greenhouse gas emissions.”

The paper says that farmers would also find it more profitable in coming years to expand livestock production in mixed systems — where livestock are fed on both grass as well as higher quality feed — rather than in pure grass-based systems. This development, they estimate, would lead to a 23% reduction of emissions from land use change in the next two decades without any explicit climate mitigation policy.






The new study also introduces yet another metric for measuring the costs of climate measures for agricultural systems, the Total Abatement Calorie Cost (TACC), which complements the pure economic metric known as “marginal abatement cost” while also seeking to capture the impacts of mitigation measures on food security.



Published in Proceedings of the National Academy of Sciences.
Source: International Institute for Applied Systems Analysis