Global warming could empty world's rice bowl

Thailand is thought to have been one of the first countries to cultivate rice, and today the kingdom is the world's largest exporter, with 7.5 million tonnes of the grain shipped overseas in 2005.

It is unsurprising that rice has gained such reverence in a country where it is eaten three times a day and is farmed by 3.6 million families, but the vital grain could be at risk from climate change.

Environmentalists and scientists say that as the world gets hotter, floods, droughts and rising sea levels could push Thailand's rice yields down significantly -- with a huge impact on rural communities.

"Farmers would get poorer and poorer," says Tara Buakamsri, climate campaigner with environmental group Greenpeace.

The Intergovernmental Panel on Climate Change predicted that greenhouse gases would change rainfall patterns, intensify tropical storms and amplify the risk of drought and flooding.

Such extreme weather has already hit Thailand. Farmers cutting the first rice of the season in central Ayutthaya province recall widespread floods last year which wiped out their crops and killed about 200 people.

"The whole province was affected by the flood," says Sangon Reungtham, 55, the cracked earth beneath her feet showing no sign of the torrents that inundated this community and damaged her home last August.

"It was the worst in my life, I had never seen rice fields under the water like that before," she tells AFP.

Rice farmers are fearful of the changes they see in the weather, but shake their heads when asked what they think is causing it.

"The weather has become hotter and hotter every year, the floods are getting worse," says Luea Kerdvithree, 50, as she scythes a handful of yellow jasmine rice husks. "I'm afraid that it is going to get worse."

Anond Snidvongs, an environmental scientist and Southeast Asia director of global climate change research body START, says extreme weather could have a serious effect on rice production.

His initial studies with Chiang Mai University found that while plants themselves would be only be slightly affected by rising temperatures, the animals and small microbes that give the soil its nutrients are very sensitive to heat and humidity.

Floods and heavy rain would erode the soil and destroy the nutrients, he says, while droughts and longer hot days parched the soil.

"We are in the process of researching how much that can reduce soil productivity, but from a very simple speculation it could be reduced by as much as half," says Anond.

A study by Vichien Kerdsuk, a researcher at Khon Kaen University, found that jasmine rice production in one northeastern region fell 45.5 percent between 1994 and 2005 because of increased drought and, to a lesser extent, floods.

Greenpeace says that rising sea levels caused by melting ice and warming oceans could also hit Thailand's coastal farms, as increased salt levels in the soil made it less productive.

Anan Polvatana, assistant director of research at the Thai Rice Institute, says researchers are trying to develop rice varieties that are resistant to heat and to the new diseases and insects it might bring.

Anan predicts that income from rice exports could fall, but said such a drop would not likely hit the kingdom's economy hard because rice only accounted for between one and two percent of gross domestic product.

But it is the millions of people like Sangon and Luea who would suffer if the world's rice bowl ran dry.