The new date for the end of the world has been placed two billion years away in the distant future — give or take a few million — when the sun will become a bloated giant in old age, cranking up the thermostat of the earth and other planets without let or hindrance. In the new apocalyptic scenario envisaged in a computer simulation by a University of St Andrews scientist O’Malley-James, the increased evaporation rates caused by the rising temperatures — a genuine no-nonsense instance of global warming — and the chemical reactions with rainwater will cause a dramatic fall in the levels of atmospheric carbon dioxide, thereby depriving plants of their means of photosynthesis, which is their staple diet.
Ironically, instead of there being more carbon dioxide in the air because of the accumulation of greenhouse gases, there will be less. By then, of course, there may not be any humans to mull over the changes either because evolution may have produced a race of supermen armed with technological wizardry which can control the fate of individuals as well as of the planet, or because they may have perished as a result of the environmental degradation caused by the over-exploitation of natural resources and the poisoning of the atmosphere.
It is also possible that mankind would have been able by then to leave their dying home planet and build settlements on a planet in another solar system. Such scenes have been portrayed by science fiction writers, notably Arthur C Clarke. Carl Sagan was more sceptical. “There is nowhere else, at least in the near future, to which our species could migrate”, wrote the celebrated astronomer in Pale Blue Dot: A Vision of the Human Future in Space. The best alternative, according to him, was “to deal more kindly with one another, and to preserve and cherish the pale blue dot, the only home we’ve ever known”.