Thursday, November 1, 2012

Growing Rice Emits More Greenhouse Gases - Methane

I didn't realize that when I eat rice I am actually promoting global warming, in somewhere! According to ScienceDaily, rice paddies absorb CO2 while they grow. During the growing process they emit methane gas - one of the greenhouse gases that is 20 times worse than CO2 in warming the globe.

Methane in rice paddies is produced by the soil microorganisms that respire CO2, just like we respire oxygen. More CO2 in the atmosphere makes rice plants grow faster, and the extra plant growth supplies soil microorganisms with extra energy, pumping up their metabolism and emitting more methane gas. As the globe gets warmer, the yield of rice paddies drops but the amount of methane emissions remained the same. Hence, the amount of methane emitted per kilogram of rice increases.

My layman explanation of the amount of methane per kg of rice

Imagine that the farmer used to produce X kg of rice per acre and emitted Y kg of methane. So the ratio is Y/X. Now global warming reduces 50% of the rice production per acre. But the emission of methane remains the same from the rice paddies. The ratio would be Y/0.5X, or 2Y/X. So the emission doubles per each kilogram of rice.

However, there are several options available to reduce methane emissions from rice agriculture. For instance, management practices such as mid-season drainage, using alternative fertilizers, switching to more heat tolerant rice cultivars and adjusting sowing dates.

Finish your rice every time!

1 comment:

  1. ha ha ha.. like ur last comment of ' finish ur rice everytime'...