If global warming is the ultimate inconvenient truth, the most important inconvenient truth about global warming policy, I argued in last month's column, is what happens in the developing world. These countries are expected to deliver three-quarters of the increase in global greenhouse gas emissions over the next generation. Beyond the developing world's impact on emissions, there is the additional reality that because so much of economic activity is mobile, policies that restrict emissions in some places but not everywhere may just relocate emissions, not reduce them.

Developing countries recognise today's greenhouse gas problem was made mostly by industrial countries, that their own energy usage per capita represents about 20 per cent of the corresponding industrial country usage and that their citizens have pressing material needs. They are also keenly aware of the uncertainty surrounding projections of economic growth, patterns of production and future energy technologies. It is easy to sympathise with their extreme reluctance to commit to levels of emissions decades from now that are lower than those industrial countries are emitting today.