The constant deluge of bad news about rising global temperatures and their impacts can make it feel like the world is ending. Is it?
If a 60-mile-wide (100-kilometer-wide) asteroid slammed into Earth tomorrow, it would render the planet inhospitable to nearly all life forms, save for the hardiest extremophiles. This mass extinction event would wipe humanity off the face of the Earth—there would be no survivors.
To some experts, this is the true definition of an “existential threat.” Traditionalists will say this term describes a risk that endangers the very existence of something—in this case, the human species. In recent years, that definition has loosened largely to encompass global warming. Scientists, politicians, and world leaders have all described the climate crisis as an existential threat to humanity. This human-driven phenomenon is already altering life as we know it on a planetary scale, but could it really lead to our extinction?
Some experts say it could, in the most extreme scenarios. Others argue this isn’t the question we should be asking. For this Giz Asks, we reached out to a variety of experts to get their take on whether climate change actually poses an existential threat to our species.Seth Baum
Executive director of the Global Catastrophic Risk Institute.
It depends on how you define existential threat. I tend to use “global catastrophic risk” instead of “existential risk” because the latter literally means risk to existence. I would argue that in terms of extreme catastrophes, we should care about more than just existence.
If we continue to exist as a species or a civilization, but in an extremely diminished state on an ongoing basis, that’s also important. And in fact, some of the definitions that are used for existential risk include both a loss of existence—like human extinction—and also lingering on in a very diminished form. This, to me, feels like an abuse of the phrase existential risk, because our existence hasn’t actually been lost.
In general, however, I am concerned about scenarios in which there is a collapse of human civilization. You can have a whole other conversation about what that means, but basically, I’m talking about the world as we know it no longer functioning. And if there are any survivors, they’re carrying on in a significantly diminished state.
Human civilization emerged within the last 10,000 to 12,000 years, but the human species is said to be about 200,000 years old. Why has civilization only recently emerged? One explanation for this is that within the last 10,000 years, Earth’s climate has been very favorable. It’s the Holocene period of the climate, where temperatures have been fairly warm and stable.
There’s a theory that says those stable, warm conditions are what enabled us—a species that had a latent capacity to produce civilization—to actually pull it off. Indeed, agriculture was invented in at least five or six different places around the world, all within this same 10,000 year period. This suggests that without the Holocene, we couldn’t pull this off. With that in mind, if we now start to push the planet outside of these nice, warm, stable, favorable Holocene conditions, perhaps we are destroying the precondition for our civilization.
Then, you can start to look at the details. How is the climate changing? How will that affect human populations? There’s plenty of concern about how this will affect agriculture, water resources, and extreme weather. All of that stuff starts to paint a picture of a scenario in which our ability to survive this as a civilization is in question.
The other important detail is that climate change doesn’t happen on its own. In this way, it’s different from a lot of other catastrophe scenarios, like getting hit by a large asteroid. Climate change is a gradual process, and so we have to think about not just climate change on its own, but how it affects everything else going on—including other catastrophic risks. Does climate change make nuclear war more likely? Could climate change push society to take dangerous risks with artificial intelligence? We’re actually seeing little bits of that right now. It can be helpful to think less about whether climate change is a catastrophic risk on its own, and more about whether it increases the risk of global catastrophe.
