One of the most difficult questions to answer at Copenhagen is just how far are the Chinese prepared to go to halt climate change. What is their bottom line?
I think they do want a deal and they do want action that will be effective in taking on global warming. But they are being inscrutable over what exactly they are willing to do themselves.
It's not as if the Chinese don't "get it" with climate change. In fact, they understand better than many other countries what can happen – they can already see the effects of climate change in the desertification of the north-west of China and the dust storms over the capital. They can stare in the face the impacts of water shortages.
But the one thing that is absolutely clear is they are negotiating extremely hard and are resisting any moves that they think will push them into a corner. At the same time, they are signalling that they are very unhappy with other countries' positions. Like many of the developing nations, China feels the West isn't taking enough of the burden.
In some ways this is a surprise because earlier this year China announced it was willing to accept a Carbon Intensity Target. The target would not necessarily mean that the Chinese would sign up to cutting carbon emissions but they would reduce the rate at which emissions would increase.
It struck me at the time that this was a deliberate attempt to help Barack Obama with his own difficulties in the US Senate while the Waxman-Markey climate change bill was being debated. I think the Chinese thought that would lead to the West being a little bit more willing to agree to cuts than has been apparent so far.
Equally, there could be an element of Chinese resentment at being monitored, especially if they felt they were being checked up on by the West.
It's a question of national sovereignty, as the Brazilians have often pointed out in the past, and of how much control a country exerts over what is happening in its own territory.
What happens today is likely to be crucial. It's the time when the leaders are here, the time when each country's real position is likely to be revealed.
By the end of today, or perhaps some time tomorrow, we should have the answer to exactly what the Chinese want out of the Copenhagen conference.
Tony Juniper is former director of Friends of the Earth