The climate impact of rice

After 15 years of marriage, my wife has finally stopped grumbling that I’ve cooked too much rice for dinner. I have not cooked too much rice – I have cooked enough for breakfast as well. Having grown up in Madagascar, I am at least partly Malagasy, and the part of me that is most Malagasy is my appetite for rice. I had it for breakfast today, with wilted spinach, chilli and a handful of roasted peanuts, and this feels more normal to me than a bowl of cornflakes.

However, rice is a slightly complicated food to love as a climate writer. It has an outsized impact on the atmosphere, second only to meat. This is clearly shown in this graph from a recent Nature article, which estimates contributions to global warming from food by 2030.

Before I say anything else, it’s important to note that rice is the staple food for half the world. One reason that it looms so large is that we just grow so much of it – enough for 4 billion people to eat it pretty much every day.

On the other hand, we grow an equally vast quantity of wheat, which takes up more of the earth’s land than any other crop. That doesn’t have anywhere near the same consequences for the atmosphere. Neither does maize (corn), the world’s most popular crop by tonnage, though some of it is used for fuels rather than food. All other grains together add 3% to global warming in the estimate above, with rice accounting for 23%.

The reason for this is that rice production has a methane problem, in common with meat and dairy. Rice is grown in rice paddies, which are routinely flooded as part of the farming process. This results in organic material rotting down underwater, which releases methane. Since methane is 25 times more powerful as a greenhouse gas than CO2, it does far more damage to the atmosphere.

The irony is that rice cultivation is itself highly vulnerable to climate change. Because it uses so much water, it’s a crop that doesn’t tolerate drought. It doesn’t grow well in extreme heat, and higher temperatures also increase evaporation from the fields, compounding the water problem. Lots of rice cultivation happens in river valleys and deltas, where water is available. Though it likes to have wet feet, too much water will ruin the crop too, making it vulnerable to an increase in extreme rainfall and flooding. All together, some projections suggest that climate change will drive a 40% fall in rice production by 2100, with more people to feed than ever.

The good news is that there is another way to grow rice that don’t produce as much methane: Sustainable Rice Intensification, or SRI. Growing rice is a deeply cultural practice, so it takes some convincing to encourage people to ignore the conventional wisdom and stop flooding their rice paddies. Fortunately SRI also delivers substantially higher yields, while using less water. That, in turn, means more money for farmers. So once they are aware of it, rice growers have every reason to try it.

Sustainable rice intensification is now commonly used across the global south, with American rice farmers slowly catching on. A number of countries have added SRI rice to their Nationally Determined Contributions to the Paris Agreement, using it as a key part of their emissions reduction strategies.

With the support of government policy in places such as India or Vietnam, there has been a huge amount of research into SRI rice. Scientists and agricultural research institutes have refined its techniques and mechanised them. There are even apps these days for managing your SRI rice field. It’s an approach that has made a huge difference to emissions already, and improved the lives of millions of smallholder farmers along the way. And with major initiatives behind it such as ClimateRice or SRI-2030, there is a lot more to come.

Those of us who are even a little bit Malagasy would like you to know that SRI rice was invented and developed in Madagascar – and a good story it is too. (Many farmers in India refer to it as ‘the Madagascar method’ rather than SRI.) In my view, it is Madagascar’s big contribution to climate change, and it is with that in mind that I intend to continue having rice for breakfast, however eccentric it may seem to my family.