But look beyond fossil fuels for the most intriguing trends. One is that the energy intensity of the world economy - the amount of energy it takes to produce one dollar's
of income - keeps falling, at a rate of about 2 percent. What this means is that even without any change in the
shares of fossil-based and fossil-free sources in the world's energy mix, we could have 2 percent annual economic growth without increasing carbon emissions from energy use. Of course that is not enough to
climate change and we need more economic growth than that. It is
a stunning number, which refutes the claim by some environmentalists that permanent economic growth is fundamentally incompatible
finite physical resources.