Thailand is the world's sixth largest producer of rice and the world's largest exporter, selling around 10 million tonnes in 2008 and contributing about a third of the total world rice trade. Rice is also the staple food of the Thai population, regardless of their income.
During growth, rice plants are very sensitive to extremes of temperature. Crops can become sterile if temperatures exceed 35 °C around flowering time, reducing the amount of rice available for consumption. Low temperatures during other stages of the plants' growth can also have a significant negative effect on yield.
With a global temperature rise of 4 °C, the risk to rice crops from low temperatures may decrease, but this is likely to be offset by reductions in yield across Thailand due to the higher temperatures. With the hottest days of the year as much as 6 °C warmer over parts of the country, and without adaptation measures, the possibility of rice sterility is significantly greater. Rice crops may also be affected by an increased risk of drought. The potential of a relative sea level rise of 65cm across parts of the country brings an increased risk of salt water intrusion on vulnerable coastal agricultural land, also threatening rice yields.
Because of the importance of rice to Thailand, significant reductions in yield would threaten national food security in addition to damaging the country's economy. As rice is also the principal staple crop of Asia, any deterioration of rice production systems could prejudice food security in the continent as a whole.
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