In Thailand, rice agriculture is so much a part of the culture that the verb “to eat” in Thai translates literally as “to eat rice” and it is rare that a meal doesn’t include this staple grain. A common greeting is “gin kow reu yung” which translates as “have you eaten rice yet,” and it is customary to invite someone who has not yet eaten to share a meal.
Rice is also critical to their economy. In 2007, Thailand produced 28 million of the 636 million tons of rice produced worldwide. That year, Thailand exported 9 million tons of rice, more than any other country, giving it the title “the rice bowl of Asia.”
Historically, Thai farmers grew thousands of rice varieties, although genetic modifications have reduced that number drastically. Still, throughout the year, there are dozens of ceremonies using different varieties of rice, including black, yellow, red, white and sticky rice. In fact, following the traditional recipe for a single dish can require up to thirty rice varieties.
The 2008 food crisis demonstrated the effects that rising rice prices or potential shortages can have on global food security. This is no surprise as rice is the only major grain grown exclusively for food and provides over one fifth of the calories consumed worldwide. Worrying politicians and farmers alike is the prospect that climate change has, and will continue to, harm rice yields. A study by Okayama University in Japan found that grain yield declines when the average daily temperature exceeds 84° Fahrenheit (29° Celsius), and grain quality continues to decline as temperatures rise. Complicating the situation further is the fact that some efforts to bolster rice production in the face of this adversity may only make the long-term problem worse.
Rice accounts for 16% of global nitrogen fertilizer use, 13% of phosphate fertilizer use, and 13% of potassium fertilizer use (chemical fertilizer requirements per unit of output for rice are on par with those for maize, but are less than those for wheat and substantially more than those for soybeans). In 2006-2007, rice crops in Thailand alone required 299,000 tons of nitrogen fertilizer. Chemical fertilizers contribute to greenhouse gas emissions, decrease soil fertility, have harmful health effects, and drive many farmers into vicious debt cycles. However, the common alternative to the heavy use of chemical fertilizers, organic farming, is no panacea. In this case, organic fertilizers may not help in the way they can with corn and wheat, because methane is emitted through the fermentation of organic matter in flooded paddies.
Methane, like carbon dioxide and nitrous oxide, is a greenhouse gas that contributes to climate change. Although carbon dioxide emissions still pose a greater problem, global methane levels have climbed to 16% of total greenhouse gas emissions. Even more problematic is methane’s potency: by weight, methane can trap 21 times more heat than carbon dioxide.
In 2005, Thailand emitted 91.6 million tons of methane, half of which were due to rice cultivation -- a statistic that is drawing international attention to the climate effects of rice paddies. Organic fertilizer alone doesn’t provide the climate solution for rice (although it greatly improves farmer health and soil fertility), but farmers have adapted other strategies for mitigating rice agriculture’s climate effects.
Many large rice mills burn rice husks for power rather than oil or coal, and some are able to sell electricity back to the government, such as the plant in Roi-Et province, a pilot project with a capacity of 9.8 MW. Burning rice husks diverts the methane that would be produced by leaving rice husks to decompose in the fields and provides a renewable source of energy with no net carbon dioxide emissions.
Another mitigation strategy is to occasionally drain rice paddies. This reduces emissions by eliminating the bacteria that thrive in the oxygen-free setting and produce methane by decomposing manure or other organic matter. A study by Thailand’s Graduate School of Energy and Environment found that a three day mid-season drainage during the rice flowering period significantly reduced methane emissions while producing only minimal losses in yield and small increases in nitrous oxide emissions. This was suggested as a compromise between the need to mitigate climate change and current socioeconomic realities.
These mitigation strategies, while strong in theory, have yet to be implemented on a large scale. As rising temperatures and irregular weather patterns harm rice yields, and as growing populations threaten food security, Thai farmers and the Thai government will be forced to further address rice production’s contributions to global climate change.
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