Can rice survive climate change?

Every June, Thailand’s fields fill with millions of farmers as they begin to plant rice, the foundation of the country’s diet. In 2015, however, the land was so dry that the government asked them to postpone the start of the season and to refrain from growing a second crop during the winter. Production fell by 15 per cent that year and it took two years for the world’s second largest rice exporter to return to former production levels.

Thailand is not the only country where rice is threatened by the changes in rainfall and temperature patterns linked to the climate emergency. In Vietnam, rising sea levels are increasing soil salinity to such an extent that the paddy fields will no longer be productive. In West Bengal, in eastern India, drought and flooding are already causing recurrent crop failures. “Rice is highly vulnerable to climate change, so factors such as sea level, salinity and temperature rises will affect rice production,” says agricultural consultant and researcher Wyn Ellis.

Many scientific investigations have confirmed how sensitive rice is to climate change. A study published in the Nature research journal, for example, shows how rising temperatures could increase arsenic concentrations in rice paddies and reduce yields by almost 40 per cent between now and the year 2100. Other studies also forecast yield losses in places as disparate as Kenya or India if adaptation measures are not taken.

In a world where almost half the population – 3.5 billion people according to the Food and Agriculture Organization (FAO) – depend on rice for a living, this fall in yields could be fatal for global food sovereignty. Asia would be the hardest hit, but the losses would be felt around the globe, with rice accounting for around 20 per cent of the total calories consumed worldwide.

Paradoxically, rice farming is also one of the biggest contributors to climate change, producing 10 per cent of global methane emissions, which explains why a total of 48 countries have included rice in the national emission reduction strategies set out in their nationally determined contributions (NDCs) to combat climate change.

Rice, moreover, takes up between 34 and 43 per cent of the total water used for irrigation around the world. “Rice uses more water than any other crop,” says Ellis, who is coordinating the Sustainable Rice Platform (SRP). Intensive rice growing also depletes the soil and lowers its fertility. “Intensive double and triple monocropping of rice in Asia is associated with the depletion of soil micronutrients, the build-up of soil toxicity and a high incidence of pests and diseases,” reports the FAO. Rice is the world’s number three crop in terms of the land dedicated to its cultivation, with a total of 167 million hectares in 2018, only behind wheat and maize.

There is, however, very little awareness about it compared with other crops, such as oil palm, soya or timber. “Rice is overlooked, despite the environmental impact [of these other crops] being much lower,” says the SRP coordinator. “We need to shift attention from high profile crops to high impact crops.”

This is what Ellis is working towards, as coordinator of the Sustainable Rice Platform (SRP), a project that sets social and environmental sustainability standards for rice, under the auspices of the United Nations and the International Rice Research Institute (IRRI).

The platform, which is currently working with five million farmers in 22 countries, serves as a sustainability label with criteria that farmers have to meet to be certified, such as reduced fertilizer use, integrated pest management, and, above all, good water use. “Rice needs to be seen not just as a commodity but as a crop that is part and parcel of a landscape…where smarter water use is required,” says Ellis.

It is hoped that the label’s arrival on supermarket shelves will make consumers think about the impacts of this industry and will reward sustainable rice cultivation with their buying decisions. “If we don’t take action we are going to end up with increased volatility and less stable supply chains, which will make prices skyrocket over the next 25 years,” explains Ellis.

New planting schedules and crop rotation

Vietnamese rice farmers, like their Thai counterparts, are also changing their planting schedules. In their case, however, the problem is not too little but too much water, and of the kind not suited to rice growing: seawater.

Seawater intrusion has been affecting the Mekong Delta for years, undermining the harvests in a region that produces as much as 50 per cent of the country’s rice. Rising sea levels are not the only problem. The construction of dams and poor rainfall in the upper reaches of the river also mean that the Mekong has less flow when it reaches the delta and does not have enough strength to push back the seawater, explains IRRI researcher Leo Sebastian. “We are already seeing the major impacts that climate change and events such as El Niño are having on the Mekong Delta,” says the scientist. El Niño is a weather event often accompanied by drought.

To limit the damage caused by saltwater intrusion, Sebastian is mapping the high-risk areas so that farmers know when to plant. They usually harvest in late February or March, but if they plant earlier they can harvest in early February and prevent salt intrusion from destroying the harvest,” he explains. During the 2016 El Niño event (before the map was launched), 200,000 hectares of rice paddies were affected by the rise in sea level.

Despite adaptation measures such as dikes and adapted irrigation systems, in some parts of the delta, rice will nonetheless have to be replaced by resistant crops such as coconut. “There will always be crops that can be planted. It is human nature [to seek solutions], but there will always be crops that can adapt to different conditions,” says Sebastian. Another possibility, as the scientists points out, may be a further increase in the already popular shrimp farms in the area. “It will be the market that decides what is produced,” he concludes.

Elsewhere in the world, other options are being tested to help rice survive these increasingly hostile conditions. In some places, such as Thailand, rice is being rotated with other crops, such as sunn hemp. “We are trying to discourage intensive cultivation and to encourage rotation with other crops,” explains Ellis.

Tests are being conducted with ‘aerobic’ rice, which needs much less water. In addition, some regions are leaving behind the famous IR8 variety (the high yielding variety propelling the Green Revolution that began in the 1960s) and returning to native varieties that are less aggressive on the soil. The IRRI, from which IR8 emerged, is also developing a saltwater-tolerant rice, and several laboratories are working on varieties that are more resistant to drought.

And although the history of rice belongs to Asia, Ellis assures us that the adaptation of this cereal is key to development in regions such as Africa – the continent where rice consumption is growing the most – as well as to the achievement of the sustainable development goals at global level. “We all have a role to play in making sure we have access to a sustainable food supply for years to come,” concludes the coordinator of the Sustainable Rice Platform.