A failed deal in the Copenhagen climate conference will call for an extra investment of US$500 billion to cope with global warming, the chief of the Paris-based International Energy Agency (IEA) said on Tuesday.

"If there are no immediate measures to reduce the emission of carbon dioxide, US$500 billion should be additionally invested to redeem the delay and to retrieve the trajectory" that limits the increase of global temperature around two degrees Celsius, Nobuo Tanaka said at a press conference.

Actually, Tanaka doesn't expect an international treaty to be signed at the United Nations climate conference. But a "strong commitment" would be announced, he said.

"A very firm message about the environment, which Copenhagen is dealing with, needs to be issued to investors. Without a clear message, it is very difficult for private sector to take part in the investment," he noted.

The IEA has proposed a plan to limit the concentration of greenhouse gas emissions at 450 parts per million (ppm) of CO2 equivalent, and believes this scale can hold a hike of two degrees Celsius in average temperature.

(Xinhua News Agency December 9, 2009)