KEY POINTS:
As the average annual temperature rises in many parts of the world, one of the biggest concerns is the impact on agriculture. Yet relatively little research has been done on how humanity will feed itself in a climate that is warmer and more unpredictable.
This issue is of special concern to Asia where rice is the dominant food crop and relies heavily on fresh water and fertiliser to grow and produce high yields.
Rice is grown in more than 100 countries. But nearly 90 per cent of the land used for rice is in Asia where eight countries - India, China, Indonesia, Bangladesh, Thailand, Vietnam, Burma and the Philippines - account for 80 per cent of the global rice area.
Since the Green Revolution began just over 40 years ago with the release of the first modern rice variety by the International Rice Research Institute (IRRI) in the Philippines, the global rice harvest has more than doubled, keeping slightly ahead of population growth.
That has brought market prices down by 80 per cent in the past two decades so the poor can afford it. Rice is the staple food for half the planet's population and most of its poorest people, providing about 20 per cent of the direct human calorie intake worldwide.
But the advances in plant breeding and farm management that sustained the Green Revolution are facing new challenges. World rice production is now expanding at less than 2 per cent annually and rice-growing countries are finding it difficult to raise output much beyond this level.
Global prices for rice have doubled in the past two years to reach a 10-year high. Urea fertiliser prices have tripled in the past five years.
With demand increasing relative to supply, world rice reserves are at a 30-year low, putting added pressure on rice-importing countries, such as Indonesia, to return to self-sufficiency.
Indonesia, the world's fifth most populous nation, has been struggling for several years to lift rice production. It has to pay for increasingly expensive rice imports. Shortages could trigger price rises, causing social unrest and political instability.
Experts say climate change is already affecting Asia's ability to produce rice and this could slow or even undermine efforts to reduce poverty in one of the region's great success stories, particularly in East Asia.
The IRRI is the world's leading international rice research and training centre. Based in the Philippines, it has offices in 13 other countries in Asia.
Its scientists say that both higher maximum and higher minimum temperatures can decrease rice yields.
They also say the positive effects of increased amounts of carbon dioxide, the main greenhouse gas, do not compensate for an overall decrease in rice quality from the effects of global warming.
Meanwhile, a long-term problem of fresh water scarcity is looming against a backdrop of climate extremes and sea-level rise. Almost two-thirds of the fresh water for human use in Asia goes into rice production.
Climate extremes such as more frequent or more intense flooding, droughts, cyclones and heatwaves pose incalculable threats to farming. Sea-level rise is projected to be in the range of 10cm to 85cm over the next century, depending on the climate scenario used.
The implications for rice production in some low-lying coastal areas of Asia are grave. Vietnam's rice industry, for example, depends heavily on farms in the Mekong and Red River deltas. Much of this land is under 1m above sea-level and much of the rest is at a height of just 1m to 5m.
The rice research institute is already working on ways to help Asian rice farmers adapt to adverse circumstances, establishing a group of experts to assess the consequences of climate change on rice production and find ways of overcoming or mitigating them.
New management systems are being developed to optimise water and nutrient inputs and to ensure long-term sustainability. But given the scale of the challenges facing Asia's rice industry and its food security, more money is needed to fund expanded research.
* The writer, a former Asia editor of the International Herald Tribune, is a security specialist at the Institute of South East Asian Studies in Singapore.
