When I was growing up in the 1960s and 1970s, as Lake Powell was filling, the destruction of Glen Canyon was seen as an inevitable byproduct of progress – collateral damage for the comfortable lifestyle that I and the millions of others in the arid south-west enjoyed. In the 1980s and 1990s, as the full reservoir became a world-famous houseboating destination, Glen Canyon existed only in photographs and the quixotic dreams of environmentalists.

It’s going to get drier, but with the dam still there, no guarantees how long the canyons are above water.