Global warming has the potential to dramatically slash yields of rice - the staple food for half of humanity, according to a study conducted at the International Rice Research Institute (IRRI) in the Philippines.

The troubling projections were established over 15 years of field studies at the IRRI complex in Los Banos town, south of Manila, in condiitons that approximate the way about 40 per cent of the world's total rice supplies are produced.

An IRRI report released this week concluded that there was "strong evidence of a reduction in rice yields caused by rising temperatures consistent with trends in global warming.