Contrasting interests of different countries are challenging faltering climate talks, meant to forge by December a new global deal in Copenhagen to curb man-made climate change.

Small island states say their survival is threatened by rising seas. But Saudi Arabia, the world's biggest oil exporter, says it could suffer from any pact which curbs oil demand by penalizing carbon emissions.

"It's a matter of survival for us, also. So we are among the most vulnerable countries, economically," Mohammad Al Sabban said on the fringes of talks which end on Wednesday, after the latest in a series of meetings meant to thrash out a deal to replace or extend the Kyoto Protocol after 2012.

"Saudi Arabia has not done that much yet to diversify."

Other divisions in the talks include rich versus poor, nations which contribute more to climate change than others, and countries more vulnerable to sea level rise, floods and droughts.

Saudi Arabia wants support, for example, to develop alternative energy sources and to earn credits for burying greenhouse gases underground in near-depleted oil wells.

Al Sabban said Saudi Arabia's solar power ambition was "much larger" than Abu Dhabi's $15 billion Masdar project to invest in renewable energy and build a carbon neutral city, but declined to put a dollar number on Saudi plans.

"We have a lot of sun, a lot of land. We can export solar power to our neighbors on a very large scale and that is our strategic objective to diversify our economy, it will be huge."

"We need the industrialized countries to assist us through direct investment, transfer of technologies," to ease the burden of a new climate deal, he added.

Developing nations want more cash from rich countries to help fund their fight against climate change but may have to wait until the final days and weeks of haggling in December.

Saudi Arabia wants to access an existing adaptation fund which the U.N.'s climate chief Yvo de Boer describes as a "pittance." The country may have to compete with others which want funds to prepare for sea level rise and extreme weather.

"Adaptation is not only to the impact of climate change but also the impact of climate policies," said Al Sabban.

Other Saudi demands from the U.N. talks include a re-vamping of fossil fuel taxes in industrialized countries to focus on carbon rather than energy, which may benefit oil because it emits less of the greenhouse gas compared to coal.

It also wants an elimination of subsidies for rival biofuels which it says harm the environment and hike food prices.

The new US administration of President Barack Obama has called for an increase in the amount of corn-based ethanol to be used in gasoline in the United States.

Al Sabban said Saudi Arabia was "worried" about a "dangerous" threat to its economy but would cooperate.

Environmental groups say the country has obstructed the climate talks for years, filibustering with frequent interventions in debates involving up to 190 countries.

"We get used to these allegations," Al Sabban said. "We are faithfully engaging in these negotiations. Everybody here is coming to protect their interests, we are doing the same, the EU is doing the same, the United States."