"By coming here I call attention to what China is doing environmentally and reinforce what they're doing."

Paulson, a longtime environmentalist who chaired The Nature Conservancy, said he was impressed with a programme funded by the central government to reclaim advancing desert areas near the lake by planting vegetation on sand dunes and former farmland.

He said Qinghai Lake and glaciers on the Tibetan plateau were important for the global climate because shrinkage of the lake and melting of the glaciers could permanently shift the jetstream, bringing severe weather to other continents. Likewise, carbon emissions elsewhere could hasten the lake's demise.

He said engagement on environmental issues was important to US President George W. Bush, who wants to draw China into a coalition of the world's top carbon-emitting countries to formulate a plan for reducing greenhouse gas emissions.

The tougher part of Paulson's China trip will follow in Beijing, where he will meet Vice Premier Wu Yi and Central Bank Governor Zhou Xiaochuan on Tuesday and President Hu Jintao on Wednesday.

He said he would again press for faster appreciation of the yuan and other reforms, such as rebalancing China's economy away from exports and toward more domestic consumption and increasing foreign access to China's financial services sector.

Paulson's visit comes as US lawmakers, frustrated with slow progress in reducing US trade deficits with China, are advancing legislation aimed at pressuring Beijing to allow open markets to set the yuan's value.

The US Senate Finance Committee last week passed a bill that would allow companies to seek anti-dumping duties against products from countries that have "fundamentally misaligned" currencies and eventually intervention by the Federal Reserve.

The China Daily said the currency bill smacks of strong protectionism and risks undermining bilateral efforts to reduce the trade imbalance between China and the United States.

The measure would do little to cut the US trade deficit, the English-language daily said in an editorial. The United States should concentrate instead on persuading its citizens to consume less and save more.

"Unfortunately, the new US bill tends to mislead its people into believing that protectionism can be an answer to its economic woes," the paper said.

Paulson said he was concerned about the currency legislation, saying it was the wrong approach, and he preferred achieving currency and economic reform through bilateral and multilateral dialogue.

But he understood the motivation behind it and frustrations among Americans about trade imbalances.