While much of the globe's focus in the climate change fight is on the burning of fossil fuels and the logging of rainforests, water-logged rice paddies are also a major source of global warming-causing methane.

"If you step through a rice field, there is a lot of gas bubbling out and the large bulk of that is methane," said Reiner Wassmann, a biologist specialising in climate change at the International Rice Research Institute.

While carbon dioxide is the most famous of the gases that cause global warming, methane is at least 20 times more effective at trapping heat in the earth's atmosphere.

In an interview with AFP from the institute's headquarters in Los Banos, a farming area on the Philippines' main island of Luzon, Wassmann explained that methane was responsible for one fifth of all greenhouse gas emissions.

About 10 percent of the methane comes from rice farming, while other sources include the flatulence of cows and decomposing landfill garbage dumps.

Wassmann said it was essential that rice farmers in Asia and the rest of the world did their bit to tackle climate change, but lumping them in with more obvious, fossil-burning culprits of climate change was wrong.

"Culprit gives an emotional tone to it that is not necessary," he said, describing some calls by green groups for the billions of people who rely on rice as their staple to eat less of it as being too extreme.

"I have heard suggestions like that but I don't think that makes sense. The key is on the production side, not on the consumption side," he said.

However Trinidad Domingo, a 57-year-old rice farmer with a 2.5-hectare (six-acre) plot of land in northern Luzon, said it seemed unfair to ask people such as herself to make sacrifices as part of the climate change fight.

"If we are contributing to this problem, we are just trying to survive and don't do this intentionally," Domingo told AFP from her small brick home.

"The big factories and industrialists should be the ones to be blamed. Why pick on peasants like us? They are the big contributors to the problem."

Indeed, Domingo's carbon footprint would appear to be a fraction of that of an average businessmen in the United States or elsewhere in the developed world -- she does not own a car and her main luxury is a small television.

"I am a simple rice farmer, a peasant who just wants to eat three times a day," she said.

Offering some hope, Wassmann said reducing greenhouse gas emissions from rice fields did not necessarily require a sacrifice, rather the implementing of smarter and more efficient farming strategies.

The first step is for farmers to use less water, because the methane is created when submerged organic material decomposes.

Wassmann said this was a logical path to follow regardless of the climate change issue because water would only become more scarce in an increasingly populated world.

Using less water can be done through draining the rice fields regularly during the growing season.

However the complicating factor is that nitrous oxide -- an even more potent gas and which mostly originates from widely used nitrogen fertiliser -- is released from drained rice fields.

"The only solution to that we can see is that we couple water saving... with increasing efficiencies of nitrogen fertiliser," he said, adding this could be done without sacrificing yields.

However convincing rice farmers to use less fertiliser will be a huge challenge, as evidenced by the reaction of Domingo when asked if she would change her farming techniques.

"If it contributes less to climate change, we are willing to cut down on using it, but I am afraid my crops won't grow as fast, leading to lesser yields. There could be a problem there," she said.

"We are willing to find alternatives but, at the end of the day, we are just small farmers."

Wassmann also said that there was no concerted push across the world's rice farming industries to educate and help farmers.

"As far as methane is concerned, there is not a single project in the real world, outside of the experimental farms, where there are programmes to reduce greenhouse gas emissions from rice," he said.

Wassmann also said he expected rice to be a virtual non-issue at this week's climate change summit in Copenhagen, and that he expected it would only be discussed in depth at follow-up, more technically focused meetings.