"A focus on emissions within national borders may miss the point," the report said. "Whilst the nation state is at the heart of most international negotiations and treaties, global trade means that a country's carbon footprint is international."

It said that not only were industrialised countries responsible for most carbon emissions to date, but they also had significant responsibility for driving the rapid growth in emissions from industrialising countries like China.

"Without this demand, China would not have developed so rapidly and its emissions would not have risen so sharply," the report said, proposing that so-called imported carbon be included in national emission calculations.

BALI MEETING

The issue is likely to feature heavily when environment ministers meet in December on the Indonesian island of Bali to try to kickstart negotiations on a successor to the Kyoto Protocol on curbing carbon emissions which only runs to 2012.

The findings echo those of the New Economics Foundation which earlier this month in its "Chinadependence" report accused the developed nations of "carbon laundering" their economies.

It said Britain among others was understating its carbon emissions because it in effect exported its smokestack industries to China in the 1990s and was now importing products it would have been making itself.

"Because of the way that data on carbon emissions gets collected at the international level, this has the effect of 'carbon laundering' economies like those of Britain and the US," said NEF director Andrew Simms.

China has plentiful supplies of coal but precious little other fuel for electricity generation, and is building on average a coal-fired power station every five days to feed its booming economy.

China is poised to overtake the United States as the world's biggest carbon emitter, and Washington insists that Beijing take urgent steps to curb its rising carbon emissions. The United States has not ratified the Kyoto Protocol on global warming.

The Tyndall report noted that the United States is the top destination for Chinese made goods.

It said net Chinese exports -- that is exports minus imports -- accounted for 1.1 billion tonnes of carbon dioxide or 23 percent of Chinese emissions in 2004.