The Sixth Extinction: An Unnatural History

by Elizabeth Kolbert

Everything (and everyone) alive today is descended from an organism that somehow survived the impact. But it does not follow from this that they (or we) are any better adapted. In times of extreme stress, the whole concept of fitness, at least in a Darwinian sense, loses its meaning: how could a creature be adapted, either well or ill, for conditions it has never before encountered in its entire evolutionary history?

Other calculations of his show that to keep pace with the present rate of temperature change, plants and animals would have to migrate poleward by thirty feet a day, and that a molecule of CO2 generated by burning fossil fuels will, in the course of its lifetime in the atmosphere, trap a hundred thousand times more heat than was released in producing it.

Already one plant species, Poa annua, a grass from Europe, has established itself on Antarctica; since Antarctica has only two native vascular plant species, this means that a third of its vascular plants are now invaders.