With Google pulling out of China and US senators urging the White House to exert pressure for a renminbi revaluation, friction between the world's great powers seems depressingly normal. Sadly the reality is even worse.

The mutual dependence of America and China is grounded in commercial ties, and the two sides will be doing business for decades to come. But a new conflict is unfolding that could be more dangerous even than the cold war. Soviet economic decisions had little impact on western standards of living. But today, globalisation means there is no equivalent to the Berlin Wall. Nothing can insulate China and America from each other's turmoil.

The list of irritants in US-Chinese relations reaches beyond the current rows over Google and the renminbi, to include broader cyberattacks, disagreements over Iranian sanctions, China's failure to protect intellectual property, and trade disputes over tyres and steel pipes. There are other nascent conflicts, too - from control of natural resources to the militarisation of the Indian Ocean.

These problems are symptoms of an illness that has progressed further than most observers realise. Put bluntly, Beijing no longer believes American power is indispensable to Chinese economic expansion and the Communist party's political survival. China's leadership has begun to consider a gradual shift in its global strategy. Though this will not be easy to carry out, it is now quietly embarking on political and economic "decoupling" from the US.

This rethink began when the (western) financial meltdown put millions of Chinese out of work in early 2009. The shock undermined a number of Beijing's basic assumptions. Most significantly, China had "coupled" its growth to the west, becoming an export powerhouse to ensure ever rising standards of living.

This strategy lasted for 20 years - but is now coming to a close. To the careful observer, the signs have been clear for some time. We glimpsed a new standpoint at December's climate change summit in Copenhagen and in the strong reaction last month to America's announcement of arms sales to Taiwan and to US president Barack Obama's meeting with the Dalai Lama .

David Fuller's view In the red corner we have the challenger, an emerging new superpower, gaining confidence and with a very different pugilistic style (ideological background) from the long-reigning but aging superpower in the blue corner.

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