I recently read an interesting article that forecasts the production of greenhouse gases (GHG) from ricelands by the end of the 21st century1. The authors used data from 63 studies conducted in 30 different locations in 8 different countries.
This article prompted me to try to put rice-related global and local GHG emissions into context. In other words, what are the estimated contributions of ricelands in general and California ricelands more specifically to global GHG emissions? This information is not easy to find, so I thought it would be good to share it here. I compiled estimates from two sources, the Intergovernmental Panel on Climate Change (global data, 2005) and the California Air Resources Board (California data, 2009). There are probably other estimates out there, but I think the ones I present here are reliable.
As you can see, worldwide ricelands account for 1.3% of all GHG emissions. California agriculture and forestry account for 0.06%, and California ricelands contribute a minute amount to GHG emissions on a global basis. Even when considered on a statewide basis, ricelands emissions are only 0.1% of California's total GHG inventory.
1 Van Groenigen, K. J., C. van Kessel, and B. Hungate. 2012. Increased greenhouse gas intensity of rice production under future atmospheric conditions. Nature Climate Change (http://dx.doi.org/10.1038/nclimate1712)