08/22/2017
How much does methane - from agriculture, landfills, wastewater treatment, and natural gas leaks - contribute to global warming, compared to carbon dioxide?
This is one of my most frequently asked questions here on Facebook.
The answer is: carbon dioxide - primarily from burning coal, gas and oil, but also some from deforestation, land use change, and cement manufacturing - is responsible for about two-thirds. Methane, about a fifth. Other gases make up the remainder (see graphic below).
This information comes from the NOAA Annual Greenhouse Gas Index, that measures the radiative forcing (the amount of extra heat being trapped inside the earth's climate system) due to each gas.
Read more here: https://www.esrl.noaa.gov/gmd/aggi/aggi.html
Wondering about Cowspiracy, the movie that claimed agriculture was responsible for the majority of human-induced warming? It's true that eating lower down the food chain is one of the most important ways we as individuals can reduce our carbon footprint. But in extrapolating this to the global scale, they got a few of their numbers wrong. Here's the details: http://blog.ucsusa.org/doug-boucher/cowspiracy-movie-review
