The next 50 years will bring technological, social and geopolitical change greater than we can imagine, says Astronomer RoyalÂ Martin Rees, but the emerging problems of population growth and climate change make this century arguably the most important in Earth’s 4.5 billion year history, even from the perspective of an astronomer.
It’s sometimes wrongly imagined that astronomers, contemplating timespans measured in billions, must be serenely unconcerned about next year, next week and tomorrow. But a “cosmic perspective” actually strengthens my own concerns about the here and now.
Ever since Darwin, we’ve been familiar with the stupendous timespans of the evolutionary past. But most people still somehow think we humans are necessarily the culmination of the evolutionary tree. No astronomer could believe this.
Our sun formed 4.5bn years ago, but it’s got 6bn more before the fuel runs out. And the expanding universe will continue – perhaps for ever – becoming ever colder, ever emptier. As Woody Allen said, “Eternity is very long, especially towards the end”. Any creatures who witness the sun’s demise, here on Earth or far beyond, won’t be human. They will be entities as different from us as we are from a bug.
But even in this “concertinaed” timeline – extending millions of centuries into the future, as well as into the past – this century is special. It’s the first in our planet’s history where one species – ours – has Earth’s future in its hands, and could jeopardise not only itself, but life’s immense potential.