As you might expect, scientists tend to be fairly interested in a variety of doomsday scenarios. Two aficionados of the apocalypse, astrophysicists Michael Hahn and Daniel Wolf Savin, have joined forces to conjure up several scientifically-founded plans to survive the end of the world when it inevitably occurs.
Every billion years, the Sun swells and increases in brightness by 10 percent. This leads to a temperature increase back here on Earth, which initiates geological and planetary processes that remove carbon dioxide, our primary heat insulation layer, from our atmosphere.
Without this warming layer today, Earth’s average temperature would be roughly -18°C (-0.4°F); instead, it’s about 17°C (62.6°F). Assuming that catastrophic climate change doesn’t kill us off first, the Sun will eventually brighten and swell to such a size that much of the atmospheric carbon dioxide will have disappeared.
Plants need carbon dioxide to photosynthesize. Most plants – including almost all of our crops – are C3 plants, in that they use the most common form of carbon molecule around, one that contains three carbon atoms. In about 200 million years, when the atmospheric carbon dioxide concentration drops below 150 parts per million, C3 plants will disappear.
C4 plants, which include some rice, will survive a little longer, and the two researchers suggest that we should amp up our efforts to use genetic modification to change C3 plants into C4 if we still want edible crops far into the future. Sadly, the Sun’s continuing expansion will cause even these more resilient plants to bite the bullet 300 million years from now.
Without any photosynthesis, the world would be starved of oxygen, and life will begin to perish across all ecosystems. Perhaps with the exception of some extremophiles, in 1.5 billion years, the entire world will be completely uninhabitable. Don’t fret, though: we could always casually change the orbit of the Earth.
By using rocket-powered asteroids, we could theoretically perturb Earth’s orbit just enough that it will be dragged further away from the Sun. If we’re worried about those asteroids actually smashing into the planet, then we could always use a solar sail – one that is 20 times the diameter of Earth – to capture the incoming solar wind and pull us away from our local star.
There is one more option available to us, and for a while, it involves us doing nothing at all. In a billion years from now, the world will be bathed in light, which means that solar cells will be all we need to power a wealth of advanced machinery.
If we uploaded our consciousness into these machines, we could live on as immortal, solar powered beings. This may sound impossible – and at present, it is – but in a hundred million years, we should be able to hash out a workable plan. That way, we can enjoy the scorched Earth for another 5 billion years before the Sun becomes a red giant and gobbles it up.