During my recent trip to Australia, I encountered two illusions about climate change that need to be dispelled. The first is that an ambitious outcome from the COP15 in Copenhagen this December depends largely on agreement between the US and China (the so-called G2). The idea is that the EU will agree to whatever is the most ambitious outcome China and the US can agree to, and the rest of the world simply doesn’t count. No matter how much effort a country such as Australia makes, for example, with only 2 per cent of global emissions, the impact on global mitigation will be insignificant. I disagree. This is not correct, and the reason for this is simple.