DOHA, Qatar -- As nearly 200 countries meet in oil-and-gas-rich Qatar for annual talks starting Monday on slowing global warming, one of the main challenges will be raising climate aid for poor countries at a time when budgets are strained by financial turmoil.

Rich countries have delivered nearly $30 billion in grants and loans promised in 2009, but those commitments expire this year. And a Green Climate Fund designed to channel up to $100 billion annually to poor countries has yet to begin operating.

Borrowing a buzzword from the U.S. budget debate, Tim Gore of the British charity Oxfam said developing countries, including island nations for whom rising sea levels pose a threat to their existence, stand before a "climate fiscal cliff."

"So what we need for those countries in the next two weeks are firm commitments from rich countries to keep giving money to help them to adapt to climate change," he told The Associated Press on Sunday.

Creating a structure for climate financing has so far been one of the few tangible outcomes of the two-decade-old U.N. climate talks, which have failed in their main purpose: reducing emissions of heat-trapping gases that scientists say are warming the planet, melting ice caps, glaciers and permafrost, shifting weather patterns and raising sea levels.

The only binding treaty to limit such emissions, the Kyoto Protocol, expires this year, so agreeing on an extension is seen as the most urgent task by environment ministers and climate officials meeting in the Qatari capital.

However, only the European Union and a few other countries are willing to join a second commitment period with new emissions targets. And the EU's chief negotiator, Artur Runge-Metzger, admitted that such a small group is not going to make a big difference in the fight against climate change.

"I think we cover at most 14 per cent of global emissions," he said.

The U.S. rejected Kyoto because it didn't cover rapidly growing economies such as China and India. Some hope for stronger commitments from U.S. delegates in Doha as work begins on drafting a new global treaty that would also apply to developing countries including China, the world's top carbon emitter. That treaty is supposed to be adopted in 2015 and take effect five years later.

Climate financing is a side issue but a controversial one that often deepens the rich-poor divide that has hampered the U.N. climate talks since their launch in 1992. Critics of the U.N. process see the climate negotiations as a cover for attempts to redistribute wealth.

Runge-Metzger said the EU is prepared to continue supporting poorer nations in converting to cleaner energy sources and in adapting to a shifting climate, despite the debt crisis roiling Europe. But he couldn't promise that the EU would present any new pledges in Doha and said developing countries must present detailed "bankable programs" before they can expect any money.

Sometimes, developing countries seem to be saying, "OK give us a blank check," he told AP.

Climate aid activists bristled at that statement, saying many developing countries have already indicated what type of programs and projects need funding.

"They need the financial and technical support from the EU and others. Yet they continue to promise 'jam tomorrow' whilst millions suffer today," said Meena Raman of the Third World Network, a non-profit group.

Countries agreed in Copenhagen in 2009 to set up the Green Climate Fund with the aim of raising $100 billion annually by 2020. They also pledged to raise $30 billion in "fast-start" climate financing by 2012.

While that short-term goal has nearly been met by countries including the EU, Japan, Australia and the U.S., Oxfam estimates that only one-third of it was new money; the rest was previously pledged aid money repackaged as climate financing. Oxfam also found that more than half of the financing was in the form of loans rather than grants, and that financing levels are set to fall in 2013 as rich countries rein in aid budgets amid debt problems and financial instability.

Meanwhile, the concentration of carbon dioxide in the atmosphere keeps going up. It has jumped 20 per cent since 2000, primarily from the burning of fossil fuels such as coal and oil, according to a U.N. report released last week.

A recent projection by the World Bank showed temperatures are on track to increase by up to 4 degrees C (7.2 F) this century, compared with pre-industrial times, overshooting the 2-degree target on which the U.N. talks are based.