By David Ljunggren OTTAWA, Sept 17 (Reuters) - Although countries back the idea of eliminating ozone-depleting chemicals faster than originally planned, there is no guarantee that they will agree on a new accelerated timetable at a major conference this week, a senior U.S. official said on Monday. Claudia McMurray, U.S. assistant secretary for the environment, said the main problem was working out whether the technical and financial aid available for the developing world would be enough to satisfy countries such as China. Delegates from almost 200 countries opened a week of talks in Montreal on Monday, 20 years after they signed a pact in the Canadian city to cut chemicals found to harm the ozone layer, which protects the Earth from ultraviolet radiation. The United States -- backed by the United Nations -- wants to move the deadline for phasing out production and use of the substances for developed countries to 2020 from 2030 and to 2030 from 2040 for developing nations. "We're finding there's a lot of enthusiasm for our proposal ... I can't think of a country that's opposed to it," McMurray told Reuters in a phone interview from Montreal. "But, more importantly, I think for the developing countries it will be what kind of financial assistance will they be able to get to be able to make that transition. That's what this week is all about" The Montreal meeting will focus on how to quickly eliminate hydrochlorofluorocarbons (HCFCs), which are used in air conditioners and fridges. Holes in the ozone layer are blamed for increased risk of cancer and cataracts in humans. The United States says the faster phase-out of HCFCs would be twice as effective as the Kyoto protocol in fighting climate change. Washington pulled out of Kyoto in 2001 on the grounds it would harm the U.S. economy. China is a big HCFC producer and McMurray said authorities there would "want to have some assurance that they will have the financial wherewithal to make this transition smooth. But we don't know what the number is". The United States and other nations pay into a multilateral fund to help pay for the transition to more benign chemicals. McMurray said that until the costs of the shift away from HCFCs was clear, Washington would not pay more into the fund than it does already. Whether that suits Beijing is another matter. "We'd have to make the calculations as to what the total number is and have them say yay or nay ... we're trying to put together a small group of countries to see if there's a way to find a resolution this week and that will include us and China at the very least." Asked whether China might walk away from any proposed deal, McMurray replied: "I think the real question is whether we can do it in five days, whether we can make the compromises necessary to finish it by Friday." Part of the difficulty is that no one knows how much the transition would cost, she said. "We're taking a bit of a leap to say we want this to happen. We're pushing for a result and then we're going to kind of bring the money along to meet it later ... The question will be whether there's enough data for everybody to jump together, to hold their nose and jump, if you will," she said. If nations do not agree on a deal this week the next chance will not come until signatories to the 1987 Montreal pact hold a formal meeting in Doha in November 2008. "We have a spirit of goodwill, we are looking back on 20 years of working together, and we'd like to take that spirit and see if we can push to the next level," said McMurray.
