A lot of rice production involves standing water (and the burning of rice straw between seasons), and so rice farming is a major contributor to GHG emissions:

A lot of rice production involves standing water (and the burning of rice straw between seasons), and so rice farming is a major contributor to GHG emissions: http://www.southasia.ox.ac.uk/sites/sias/files/documents/GHG%20emissions%20from%20rice%20-%20%20working%20paper.pdf http://www.southasia.ox.ac.uk/sites/sias/files/documents/GHG... It also happens to be a staple for over 60% of the world's population. And unlike transportation and energy, obvious substitutes are much harder to identify. The more I read about novel sources of GHG the more intractable this problem appears absent geoengineering.