An internal report put together by the World Bank and leaked to the Guardian claims that biofuels may be responsible for up to 75 percent of recent rises in food prices. Even environmental groups haven't gone that far in their estimates.

 More and more corn is ending up in fuel tanks rather than on plates. With soaring food prices high on the agenda for next week's G-8 Summit in Japan, World Bank President Robert Zoellick has been clear that action needs to be taken. "What we are witnessing is not a natural disaster -- a silent tsunami or a perfect storm," he wrote in a Tuesday letter to major Western leaders. "It is a man-made catastrophe, and as such must be fixed by people."

According to a confidential World Bank report leaked to the Guardian on Thursday, Zoellick's organization may have a pretty good idea what that fix might look like: stop producing biofuels.

The report claims that biofuels have driven up global food prices by 75 percent, according to the Guardian report, accounting for more than half of the 140 percent jump in price since 2002 of the food examined by the study. The paper claims that the report, completed in April, was not made public in order to avoid embarrassing US President George W. Bush.

A US analysis recently came to the conclusion that just 3 percent of the food price increases could be attributed to biofuels.

The World Bank on Friday sought to limit the impact of the leak. A spokesman for the organization, who asked not to be identified, told SPIEGEL ONLINE that the report obtained by the Guardian was just one of many internal reports prepared on biofuels and that it was never meant for publication. He pointed out that the World Bank has long agreed that biofuels were a factor in pushing up food prices but said it has declined to put a number on the impact.