China has committed to lower the emissions intensity of its economy (carbon per real yuan) by between 40 to 45 per cent from 2005 to 2020. This would be a big reduction below reasonable scenarios of what would happen under business-as-usual. Based on analysis of China’s prospects for economic growth, energy and carbon intensity over the next decade, done for the Garnaut Review, China’s emissions would come in 25 per cent lower under this target than if no action was taken to constrain them.

China’s carbon emissions would still almost double between 2005 and 2020, and make them twice the size of America’s. But on a per person basis they would remain below those in Europe, and be only half the US or Australian per capita levels.

The cut would be substantially bigger than what China would be required to do as its fair share of global action as defined by the Garnaut Review, even for an ambitious agreement. The Chinese emissions intensity reduction target is in fact similar to annual emissions intensity reductions envisaged in the Review. But it starts much earlier, in 2005 rather than in 2013, and this makes a large difference by 2020.

In terms of the absolute amount reduced below business-as-usual, China’s effort would be larger than America’s proposed cut, and would far exceed the absolute contributions committed to by Europe and Japan. This is of course a reflection of the size and underlying growth of China’s economy and carbon output, but also a measure of the ambition of the policy action.

The upshot is that developed countries need to lift the ambition of their climate change commitments and policies. Finger-pointing at China is no longer good enough.

Nevertheless China really does need to pull through with its commitment, to reduce the risk of dangerous climate change for the world. That means an innovative and sustained policy effort to bring China’s economy on to a low-carbon growth path, going well beyond the measures already in place. It will not be easy – but China now has the chance to lead the world on climate change.