It was earlier estimated that Rice farming around the world could be responsible for up to twice the level of climate impact in India. But, the researchers have found that Intermittently flooded rice farms can emit almost 45 times more nitrous oxide as compared to the relentlessly flooded rice farms that predominantly emit methane.
The analysis conducted by the Environmental Defense Fund in the US, methane and nitrous oxide emissions from rice farm could have the same long-term warming impact as about 600 coal plants.
“The full climate impact of rice farming has been significantly underestimated because up to this point, nitrous dioxide emissions from intermittently flooded farms have not been included,” Kritee Kritee from EDF, who led the study quoted as saying to news agency PTI.
But, the researchers have found that nitrous oxide emissions from rice farm can also contribute up to 99 per cent of the total climate impact of rice cultivation at a variety of intermittently flooded farms. These greenhouse emissions contributed substantially to global warming pollution — which is much more than the estimate of 10% previously suggested by multiple global rice research organizations.
“An inverse correlation between Methane and nitrous oxide emission from rice farming. Water and organic matter management techniques that reduce methane emissions can increase nitrous oxide emissions,” the study says.
Kritee further said, “Increasing pressure on limited water resources under a changing climate could make additional rice-farming regions look to intermittent flooding to address water limitations and concerns about methane emissions.”
Rice is a critical source of nutrition for the world’s speedily growing population, to provide more calories to humans than any other food, researchers said. However, growing rice is also resource-intensive: rice cultivation covers 11 % of the Earth’s arable land, consumes one-third of irrigation water.