South-east Asia is the world's rice bowl. But climate change, with its unpredictable rainfall and warming seas, is causing harvests to dwindle.

Rising sea levels are threatening rice fields. Meanwhile, the region's growing population is placing greater stress on existing farms.

While the region has managed to rapidly reduce the number of its people who go to bed hungry, around 60.5 million of the world's undernourished still live in South-east Asia, according to a 2015 report by the United Nations' Food and Agriculture Organisation.

The region's food supply will come under more pressure, with its population tipped to grow from around 600 million today to almost 750 million in 2035.

In the past, the region could rely on increasing rice yields to make up the shortfall, growing more food on the area it farmed. But yields seem to have plateaued in recent decades, not just for rice but for other main crops such as wheat and maize.

In the early 1980s, the average growth of rice yields was 3.68 per cent yearly. However, by the late 1990s, the rates had significantly decreased to 0.74 per cent per year, according to a study published in 2006.

Climate change only worsens the pressures placed upon South-east Asia. With rising average global temperatures come more extreme weather phenomena such as floods and drought, which make it hard for farmers to plant their harvests properly and protect their crops.

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And for a part of the world with coastlines as extensive as in South-east Asia, the rising sea levels caused by climate change will bring even more misery.

Dr Jauhar Ali, a hybrid rice breeder from the International Rice Research Institute (Irri), said that the low-lying Mekong River Delta is being gradually inundated by seawater, which poisons crops.

"Even a few centimetres of seawater in rice fields is destructive because once a land is salinised you can't grow anything," said Dr Ali.

In 2014, saltwater intrusion destroyed more than 6,000ha of rice fields, according to the Southern Irrigation Research Institute. And multiple sea dykes in Vietnam's lower Mekong region have collapsed as sea levels rise.

Dr Ali said: "With rising sea levels, where will the population go? To decreasing space. There will be less land and more pressure on that land.

"The major countries that will witness the effects of climate change are Vietnam, Myanmar, Cambodia and Laos. They are rain-fed areas and will see either more drought or lesser rains, and these disasters don't come knocking at the door to let you know in advance if it will be a drought year or not."

Examples of this are recent and stark. Also, climate change does not even have to hit South-east Asia directly to affect it.

"Sri Lanka, for instance, is considered a fully rice self-sufficient country. But last year, they had a severe drought. Sri Lanka then began exploring rice importation from South-east Asian countries," said Irri water management scientist Sudhir Yadav.

Dr Yadav added: "Even if climate change hits other parts of the world, that will affect global markets and food supply chains, and that can impact South-east Asia, increasing the price of rice here if there is demand elsewhere."

In a similar vein, global warming threatens Singapore's food supply, most of which comes from overseas.

Although the Republic is the world's most food-secure country, according to the Global Food Security Index published last month by the Economist Intelligence Unit, the fact that it imports more than 90 per cent of its food makes it especially vulnerable to climate change, depending on how badly other food-producing countries are hit.

And whatever food Singapore produces can also be affected by climate change. For example, recurring plankton blooms have killed hundreds of tonnes of fish in Singapore's fish farms.

In 2015, then Minister for the Environment and Water Resources Vivian Balakrishnan said that the blooms are "likely to be a recurrent problem with global warming".

Climate change does not discriminate against specific crops like rice either, and threatens all the main grains that the world depends on.

Nobel Prize winner Richard J. Roberts told The Sunday Times that farmers will need to start planting crops that are resistant to both floods and drought.

Pests are also likely to become a problem, such as the fall armyworm, a devastating caterpillar that attacks maize - a crop whose global production crossed more than 1 billion tonnes in 2013 according to the Food and Agriculture Organisation.

Sir Richard, who was in Singapore last month for a public talk organised by Wildtype Media Group, said that genetic modification was crucial to combat pest outbreaks.

"Big agri-business made Bt maize. Bt is this toxin produced by a bacteria that is a very good pesticide, and so instead of spraying it on plants you can put the gene for Bt toxin into maize. At that point, it will then be resistant to the insect," he said.

He said that while critics of genetically modified foods were halting the progress that could be made on that front, he felt that the tide was slowly turning in their favour.