UN climate talks opened in Poland today with pleas for urgent action to fight global warming despite the economic slowdown, and a warning that inaction could mean water shortages for half the world by 2050.
US president-elect Barack Obama also won praise at the opening ceremony of the talks among 10,600 delegates from 186 nations for setting "ambitious" goals for fighting climate change.
"Our work on the natural environment should be timeless ... irrespective of the economic situation," Polish prime minister Donald Tusk said amid worries that the financial crunch is distracting from a drive to agree a new UN climate treaty.
"We must understand, and let this idea be a landmark of this conference, that financial crises have happened in the past and will happen in the future," he said.
The talks in the western Polish city of Poznan are the half-way point in a two-year push to agree a climate pact at the end of 2009 to succeed the Kyoto Protocol, which sets 2012 goals for 37 rich nations to cut greenhouse gas emissions.
"The financial crisis should not prevent the commitment to other urgent issues like climate change," said Danish prime minister Anders Fogh Rasmussen, who will host a meeting in Copenhagen in late 2009 meant to agree the UN deal.
Rajendra Pachauri, the head of the UN Climate Panel, said that many people had still not woken up to the risks of what could be "irreversible change" if the world failed to act. By illustration, he said the number of people living in river valleys with water stress could rise from more than 1.1 billion in 1995 to more than 4.3 billion in 2050, or "almost the majority of humanity".
It was also possible that the Greenland icecap could melt down. Ever more species of animals and plants were at risk of extinction, he said.
Yvo de Boer, head of the UN Climate Change Secretariat, said the world had to step up work to reach a deal by next year. "The clock is ticking, work now has to move into a higher gear," he said.
The WWF environmental organisation handed out walnuts to delegates as they arrived at the conference centre and urged them to "crack the climate nut". Greenpeace unveiled a three metre high sculpture showing the planet threatened by a giant wave of wood and coal.
Mr Rasmussen praised Mr Obama's policies after years of disputes between Europe and Washington over the policies of George W. Bush. "I am delighted to see that Obama is planning ambitious climate and energy policies as part of the solution to the economic slowdown," he said.
Mr De Boer also described Mr Obama's policies as "ambitious".
Mr Obama plans to cut US emissions of greenhouse gases to 1990 levels by 2020. US emissions, mainly from burning fossil fuels in factories, power plants and cars, are about 14 per cent above 1990 levels. Mr Bush's policies foresee a peak only in 2025.
In Europe, the economic slowdown has exposed doubts about the costs of an EU goal of cutting greenhouse gas emissions by 20 per cent below 1990 levels by 2020.
U.N. talks host Poland, which gets 93 per cent of its electricity from coal, and Italy are leading a drive for concessions in a package meant to be agreed at a summit of EU leaders in Brussels next week.