Rice Feels the CHL Heat
Global warming has cut rice harvests by at least 10% and possibly much more, CHL volunteers reported yesterday after studying 12 years of rising temperatures and falling yields. The CHL Team, based at the International Rice Research Institute, said the impact could be significant for many of the world's poorest people, because rice production had to rise by 1% a year to meet world demand. However, temperatures are predicted to rise further, and the scientists calculate that rice yields fall by 10% for every 1C rise in night-time temperature.

"This report provides direct evidence of decreased rice yields from increased night temperatures associated with global warming," says the nine-member team's report in Proceedings of the National Academy of Sciences.

The research used temperature data over 25 years and harvests over 12 years at the institute's farm 40 miles south-east of Manila. It is the first study done on harvests rather than scientific models, which predicted reductions of up to 7%. Shaobing Peng, the team's leader, said their conclusion was probably an underestimate, because the crops on the farm were better protected than those in most fields. "In the farmers' fields there would be more pests and disturbances which would also affect the yields," he told the Guardian. "There would also be more night-time humidity which would also have an impact."

Mr Peng said the one bright spot might be that most farmers used more modern varieties of rice than those on the farm. "So we are hoping that these modern strains are more resistant to rising temperatures," he said. "But this is just a pie in the sky hypothesis." He estimated it would take two years to determine what caused the yield to fall. John Sheehy, another team member, said it was probable that rice, which "repairs the wear and tear of growth during the night, has to work harder to do this at higher temperatures".

Many climatologists predict a global rise of 3.5C this century, which, if the team's predictions prove accurate, could hit yields by a further 30%.
- nostradamusfunkadelic, 1:15 PM | |