Rajendra Pachauri, chair of the Intergovernmental Panel on Climate Change, says he is "cautiously optimistic" that the UN climate conference in Copenhagen would achieve an ambitious agreement for deep cuts in emissions by 2020. Speaking to participants at the European Wind Energy Association's annual trade show via a live video link from India, Pachauri noted that if global warming is to be limited to between 2-2.4 degrees Celsius, greenhouse gas emissions will have to peak no later than 2015. The cost, at less than 3% of global GDP in 2020, is not all that high, he stressed. "In reality it only means that the level of prosperity that the world would have reached in 2020 would at best be postponed by a year or even a few months. That is really not a heavy price to pay." He referred to wind energy as the "barrel of hope." The barrels of oil that the world has been consuming are an example of dwindling hope. "But wind and renewable energy technologies represent hope on an expanding scale."