Earth is a very rare jewel of a planet. A completely serendipitous chance encounter with a Mars-sized impactor some 4.5 billion years ago created our anomalously large moon which to this day gives our planet its stable axial tilt. All of which enabled our planet to evolve its current life-rich biosphere.
Yet only in the last 300,000 years or so have we been around long enough to watch Earth’s civilizations come and go. And only within the last hundred years have we created weapons of mass destruction so powerful that if used in anger, they could wipe out billions of years of biological evolution.
Given recent geopolitics, however, in fifty years’ time I wouldn’t bet on there being anybody here to ponder such philosophical musings.
Thus, could life survive a full-scale nuclear war?
A nuclear Armageddon might be broadly similar to the K/Pg impact (the “dinosaur killer”) some 66 million years ago, Ariel Anbar, a geochemist and President’s Professor at Arizona State University in Tempe, told me via email. But in terms of the energy released the impact was thousands of times larger than even an all-out nuclear war would release, he says. Nuclear war also brings with it radiation that can drive mutations, which is a special kind of “nasty” but both scenarios are more than enough to bring down human civilization, says Anbar.
Most if not all of humanity would simply disappear.
My suspicion is that something like 99.9% of all humans would die, and our civilization would never rebound, Bruce Lieberman, a paleontologist and evolutionary biologist at the University of Kansas in Lawrence, told me via email. Either we wouldn’t survive, or it would be so bad for those few that lived that they would be better off if they didn’t survive, says Lieberman.
But Would Our Biosphere Survive?
Earth’s biosphere would survive even though it would take a big hit, says Anbar. Leaving aside the consequences of radioactive fallout, a nuclear war would be less severe than the K/Pg impact some 66 million years ago, he says. The consequences of nuclear fallout from a global exchange are hard to gauge since there’s a lot we do not know, says Anbar. But plenty of animals would likely survive so evolution is not likely to be “reset” back to microbes, he says.
How would nuclear Armageddon compare to natural planet killers that have befallen planet Earth, such as giant asteroids, comets as well as nearby gamma ray bursts or supernova explosions?
Life eventually rebounded after each of these mass extinctions, though it took at least 10-20 million years for diversity to reach former levels and for ecosystems to return to their pre-extinction levels of complexity, says Lieberman.
Even so, Lieberman says a global nuclear holocaust would cause a tremendous initial loss in biodiversity, perhaps on the order of 70% to 95% of all animal and plant species on land and 25% to 50% in the oceans.
The lesson here is that our planet’s fate can turn on a dime.
At the time I began writing this post, I happened to be walking the back streets of the French Mediterranean port city of Antibes. For all its trials and tribulations over the millennia, it’s a city that was never subject to nuclear bombardment. The whole world can still come here and marvel at its architecture and the melange of Greek and Roman civilizations that helped shaped its history.
But our world heritage could also be wiped clean in the blink of an eye. That’s the reality we currently face.
And if we do wipe ourselves out, would some remaining species evolve to take our place?
It’s an open question whether another intelligent species would emerge that does things like build radio telescopes, says Anbar. We don’t know how easy it is for such a species to evolve, and just how many things need to go “right” for that to have happened, he says.
The Bottom Line?
The appearance and proliferation of our technological civilization is a peculiar result of not only of humans being highly intelligent, but also the structure of the human hand, says Lieberman. Our hands allowed for the creation and use of tools, as well as our adoption of agriculture, he says. That last step for humans took more than 100,000 years, says Lieberman. And it’s not until many thousands of years after that, that technology really started to proliferate, he says.
