The US climate change representative said Wednesday that all countries must adopt transparency and accept external reviews of their greenhouse emissions, leaving note that global cooperation is very important to ensure that the worldwide campaign for carbon intensity reduction is heading to the right direction.

Speaking before an audience in Beijing's Tsinghua University, US envoy Todd Stern said that the United States treats the issue of transparency with so much importance, stressing that "countries need to be able to see what track the world is on generally, where we are going."

Mr Stern, who headed the US delegation at the Copenhagen climate conference last December, said that countries around the world must open up in order to properly keep track greenhouse gases inventories.

He is quick to add though that every state must in turn enjoy the confidence that other countries were actually giving their best effort in meeting their respective climate change goals.

At present, China and the United States top the list as major greenhouse gas emitters which have been largely blamed for the worsening global warming.

Beijing has earlier rejected calls to accept outside reviews on its efforts to control emissions but has pledged to slash its carbon intensity, which is the measure of emissions per unit of GDP, by up to 45 percent by 2020 and based on 2005 levels.

Critics, however, are lamenting that the Chinese plan would hardly make a dent on cutting gas emissions levels and the country's carbon intensity should continue its climb up if the plan pledged by Beijing would not be revised.

About 190 countries are discussing ways to establish a treaty that would replace the Kyoto Protocol to effectively combat climate change as the United Nations (UN) agreed to host a new round of climate talks in November at Cancun, Mexico.

UN scientists have been issuing warnings that the creeping climate change, allegedly accelerated by worldwide industrial activities, must be dealt with immediately to arrest the onset of growing disasters that could potentially wipe out entire species.