Businesses must not sink money into high-carbon infrastructure unless they are willing to lose their investments within a few years, the US lead negotiator on climate change has warned.

"We want to be in (the new UN climate pact), we want to be pragmatic, we want to look at the science," said Jonathan Pershing, the head of the US delegation, during the talks on cutting greenhouse gas emissions in Bonn last week. So how will the Obama administration reconcile political "pragmatism" with the scientific realities?

Four of the world's top airlines have backed a global scheme to curb carbon emissions and hope the proposal will be included in a broader UN pact to fight climate change.

It is the first time airline firms have banded together to make recommendations to UN climate change officials on how to tackle the sector's carbon emissions.

It will be hard work getting rich nations to agree cuts in greenhouse gases that are deep enough to satisfy the demands of developing countries at climate talks, UN's climate chief told Reuters on Monday.

Some 175 nations are meeting this week in Bonn in one of a series of UN-led meetings meant to forge a deal in Copenhagen in December to replace or extend the Kyoto Protocol.

A hydropower plant on the upper reaches of China's Yellow River was this week approved by the United Nations to sell carbon credits, making it the biggest hydro project to do so, Xinhua reported on Friday.

Small island states have sharpened their calls for the rich to make deep cuts in greenhouse gas emissions, saying low-lying atolls risk being washed off the map by rising ocean levels.

environment Amelie Herenstein

India is a key player in influencing global climate change initiatives. It plays a major part in the global reduction of greenhouse emissions. Energy efficiency is one way to reduce greenhouse emissions. According to the McKinsey Global Institute's report of July 2008, cost-effective energy productivity could reduce the energy demand by half, and substantially prune greenhouse gas emissions.

Climate change may cost California tens of billions of dollars annually in coming years as sea levels rise and hot days cause people to turn up the air conditioning, a draft report from the state said on Wednesday.