Food waste is a big problem in the U.S. and (presumably) many other parts of the world as well. From Scientific American:

According to the U.S. Department of Agriculture’s Food Loss Project, we throw away more than 25 percent—some 25.9 million tons—of all the food we produce for domestic sale and consumption. A 2004 University of Arizona study pegs the figure at closer to 50 percent [...]

In the U.S., the Environmental Protection Agency has requirements in place for landfills to monitor methane emissions, and capture these emissions at higher concentrations. Again, I presume similar regulations are in place for many countries around the world.

First, is it safe to assume that methane emissions from landfills come predominantly from food waste? The only other significant source I can think of is pet waste, but I doubt the quantity would compare to food waste.

If this is true, how much of the energy stored in food waste is ultimately captured? This could be by incineration and/or conversion to biogas. Ultimately I'm interested in a global figure, but values for specific countries around the world would also be interesting.


Inspired by the question I throw compostable food into trash — how much harm do I cause?

Any organic material decomposing in a anaerobic or near anaerobic situation will produce methane.

I question your assumption that the source in landfills is mostly food in origin from individuals. Other sources:

  • Processing waste -- All those corn husks, apple pulp from making applejuice.
  • Grocery store waste -- imperfect veggies, old food.
  • Yard waste. Grass clippings, pruning
  • Wood waste. Construction, wood chips from arborists.
  • Agricultural waste. Probably not a big component. Most ag waste is used on the farm in one way or another.

Example: One of the scariest methane sources in our future is likely the thawing of the Arctic permafrost, and the warming of the Arctic continental shelves. google 'arctic methane sources climate change'

  • 1
    I would tend to include your first two bullet points -- processing waste and grocery store waste -- as a subset of food waste. I hadn't thought of yard waste however -- given that grass is the biggest crop in the U.S. this probably does make up a huge portion. Regarding permafrost, that certainly is something to be concerned about, but I'm mostly interested in methane from landfills in this question. – LShaver Oct 9 at 14:02

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