It’ll stabilize, not run away---that’s survivable.

Some climate scientists think that calling climate change an existential threat is misleading. “I don’t think it’s an existential threat to humanity or ‘life on Earth,’” Daniel Swain, a climate scientist at the University of California, Los Angeles, told Grist. “There’s this popular notion that there’s some level of warming after which the warming becomes self-sustaining, which is actually not our understanding as physical scientists of how the climate system works.”

Scientists have long known that climate change may have “tipping points,” levels of warming at which certain parts of the climate system, like ice sheets or coral reefs, will not be able to recover. Though it’s true that passing any of these tipping points would mean a substantial increase in warming, as far as scientists know, none of them will create a situation in which the planet must keep warming forever. (Put another way, Earth isn’t Venus — which famously had a greenhouse effect so strong that it evaporated the planet’s oceans.)

It’s still true that climate change could cause serious and potentially catastrophic consequences. In extreme scenarios, it could mean large-scale transformations of human society. It could also threaten the existence of particular countries, cities, or groups. “I do think climate change poses an existential threat to specific demographics of people and to specific species and ecosystems,” Swain said. “And that really should concern us greatly.”

The problem with the existential threat narrative is that it might reinforce a sense that it’s too late to do — well, anything. Some activist groups, like the U.K.-based Extinction Rebellion, have managed to turn fear of human demise into a call to action. But they have also received criticism for, among other things, telling school children that the risk of climate change means they may not live to adulthood. Such scary messages might push people into eco-anxiety, or worse, paralysis.

“I’m seeing more and more of this eco-anxiety immobilizing people to the point of just giving up, or saying there’s nothing that we can do,” said Jacquelyn Gill, a professor of climate science at the University of Maine.

Swain similarly reported receiving phone calls and emails from young people “essentially telling me that they feel various levels of depression or fear or anxiety over the fact that they’re going to die soon because of climate change.” Though these students are likely a small subset of the population, their concern still shows how the fear of human extinction has run wild in certain groups.

Gill argues that activists and members of the public need to stop thinking about climate change as an “on-off switch” — either doomed or not doomed — and move toward thinking of it more like a “dimmer switch.”

“If we can act now we will prevent more people from dying, we will prevent more species losses,” Gill said. “That to me feels like a good motivation to try to do better.”

That’s part of the reason that climate scientists have criticized activist rhetoric that humans have until 2030 to stop dangerous climate change. Sure, it might soon be too late to meet some of our most ambitious climate goals, such as keeping warming to 1.5 degrees Celsius, yet any amount of action in the present will help create a less overheated planet in the future.

So is climate change an existential threat? According to the scientific definition, likely not. As far as scientists can predict, a warming planet won’t cause changes so severe that they threaten the survival of the entire human species. And there is evidence that some of our most pessimistic projections may be exaggerated (though a Hothouse Earth wouldn’t be so fun).

That’s the sort-of good news. The bad news is that saying climate change won’t kill all of humanity is … pretty much the lowest bar possible.

In the meantime, politicians should be careful not to deploy the term “existential threat” too loosely. In all likelihood, they don’t mean that human life on the planet will go extinct. They mean that climate change is a really, really big deal and must be taken seriously. That should be sufficient reason to act.