UPDATE 1-UN climate boss warns of "cheap, dirty" energy fix

(Recasts with U.N. briefing)

By Alister Doyle and Gerard Wynn

POZNAN, Poland, Nov 30 (Reuters) - The world must avoid a "cheap and dirty" fix for the economy that could undermine the fight against global warming, the U.N.'s top climate official said on Sunday.

Yvo de Boer said the world risked a second financial crisis if governments reacted to economic slowdown by building cheap, high-polluting coal-fired power plants that might then have to be scrapped as climate impacts hit.

"What concerns me most is that the financial crisis will lead to a second set of bad investment decisions," he told a news conference before Dec. 1-12 talks involving 186 nations working on a new climate treaty.

"I hope that the second financial crisis is not going to have its origins in bad energy loans," he said.

Short-sighted investments could lead to a need to build new low-carbon solar or wind power plants in 10-20 years.

The Poznan talks are the half-way point in a two-year drive to work out a new climate pact by the end of 2009 in Copenhagen to succeed the Kyoto Protocol, which binds 37 industrial nations to cut greenhouse gas emissions until 2012.

De Boer said the economic slowdown was an opportunity to re-design the world economy.