Rice paddies rarely get mentioned in climate change discussions. Nevertheless, their impact on the atmosphere can be surprisingly large, releasing between 25 and 100 million tonnes of methane annually – potentially as much as 17 per cent of global methane emissions. With rice production likely to escalate over the coming decades to feed growing populations, and methane up to 20 times more effective at trapping heat than carbon dioxide, that adds up to a significant amount of warming from a simple bowl of rice.
However, research by biochemists in Sweden, China and the United States has led to the production of SUSIBA2, dubbed the world’s first ‘climate-friendly rice’ thanks to the dramatically reduced quantities of methane emitted by the paddies where it is grown. By isolating a gene in barley that controls the plant’s usage of carbon, the scientists were able to splice it into common rice to create the new genetic strand. SUSIBA2 directs more carbon into the rice grains themselves – hence, larger crop yields – and less into the plant roots, where bacteria would convert it into methane via the process of methanogenesis. ‘This is a win-win finding,’ says Christer Jansson, Director of Plant Sciences at the Environmental Molecular Sciences Laboratory. ‘The process results in reduced methane emissions and also results in more biomass – more food. This dual effect is very positive.’
While trials of SUSIBA2 have already taken place in China, lead researcher Chuanxin Sun from the Swedish University of Agricultural Sciences explains there are still roadblocks to overcome before the rice can be available in any large-scale commercial operations, not least objections towards farming any genetically-modified crops. ‘We plan to cultivate SUSIBA2 rice on a large scale, and at different rice cultivating zones,’ he explains, ‘to gain more data on how geographical and cultivating conditions affect its activity in cutting methane emissions.’
This article was published in the February 2016 edition of Geographical magazine.