more than 3.5 billion people depend on rice for  more than 20 per cent of their calories.  

But traditional rice farming uses up to a third  of the world's freshwater supplies and produces  

harmful greenhouse gases – as much as the entire  aviation industry before the pandemic.  

A key problem is methane production,  due to the custom of keeping fields  

flooded during the growing season. The gas is a significant contributor to  

global warming, with rice cultivation the second  biggest agricultural source after livestock.  

Researchers are currently working to  generate new, high-yield varieties that  

can be seeded directly into dry ground. A new farming method for paddy fields could  

also reduce both water use and  greenhouse gas emissions.  

It alternates wetting and drying, rather  than always keeping paddies flooded.  

Far less methane is produced when  fields are drained and organic matter  

isn't left to rot under water. Farmers are also being encouraged  

in the use of practices such as laser land  levelling, which produces flatter paddies.  

These in turn allow farmers to reduce their  use of both water and fertiliser.  

Aid group the Sustainable Rice Platform,  which promotes the wetting and drying method,  

started in 2015 and has grown to 500,000  farmers across 21 countries today.  

It says pilot projects have on average  reduced water use by 20 per cent,  

and greenhouse gas emissions by 50 percent. But these projects cover less than one percent  

of rice production worldwide and persuading  significant numbers of farmers and governments  

to commit to environmental and cost  efficiencies will take time.

Rice is not internationally traded to the  same extent as other food products.

As a result, it has attracted  less attention from pressure  

groups concerned with workers'  rights and the environment.  

But as demand for rice grows,  along with the world's population,  

and with sustainability rising up companies'  and governments' agendas, the commodity's carbon  

footprint is gradually coming into focus.