Self-parody is the first portent of age.

There are signs that the age of petroleum has passed its zenith. Adjusted for inflation, a barrel of crude oil now sells for three times its long-run average. The large western oil companies, which cartellised the industry for much of the 20th century, are now selling more oil than they find, and are thus in the throes of liquidation.

The older generation had greater respect for land than science. But we live in an age when science, more than soil, has become the provider of growth and abundance. Living just on the land creates loneliness in an age of globality.