Climate change experts from around the world will get their first chance this week to discuss the nuts and bolts of the new global warming agreement designed to take effect after 2012, that was hammered out in Bali last December.

In Bonn, “the real work is now only beginning,” says Yvo de Boer, the United Nations’ top climate change official.

But the Summit could be overshadowed by mounting criticism over how some climate policies are adding to record energy and food prices. The policy of biofuels is likely once again to come under scrutiny, although the UN looked like it was defending the practice. “While growing crops for biofuels has some influence on food prices, clearly other factors like increasing wheat consumption and hoarding of rice also play a significant role,” the UN’s climate chief Yvo de Boer said.

The other main stumbling bloc on any deal is, as usual, the US, with many believing nothing will now happen until after the US election.

Delegates say such major decisions must wait for the new U.S. administration next January. “It’s unlikely we are going to make lot of progress this year because we need strong signals from the US, and that’s not going happen until the election,” said Ian Fry, the delegate from the tiny Pacific country of Tuvalu.

He may be underwater by the time Bush finally leaves office.