o the scope for cultural evolution is much greater than for genetic evolution. A simple example is the cultural adaptive radiation of humans in the Holocene. We recently spoke about 7,000 languages, most of them associated with more or less distinctive social and subsistence systems. A few languages—Spa

t of the computer models, condemn us to four or five degrees Celsius of global warming - - enough to take the world utterly out of the rhythms of the Holocene, enough to call into question our ability to grow sufficient food or find sufficient water. The next decade is decisive because trajectory counts f