See Ask MIT Climate: Why do some people call climate change an “existential threat”?
That more literal-minded reading of the phrase “existential threat” may not be the best reflection of the risks of climate change, however. “Even under our most dire predictions, human society is still around,” says Adam Schlosser, the Deputy Director of the MIT Joint Program on the Science and Policy of Global Change and a climate scientist who studies future climate change and its impact on human societies. “I do not personally view this as an extinction issue. But there are going to be unavoidable consequences, and disasters especially for coastal communities, coastal cities, and island nations.”
Which brings us to Setiya’s second definition of an “existential threat.” Even if humanity does reduce greenhouse gas emissions enough to stave off the worst effects of climate change—and learn to adapt to some warming that is already inevitable—Setiya says that climate change still threatens to eradicate a host of human cultures, traditions, and languages. One example he gives is the Inuit peoples who are indigenous to Arctic regions, and whose cold-weather culture is under threat as the amount of ice in polar regions continues to decline. Residents of low-lying islands face an immediate, existential threat to their cultures as rising sea levels could submerge their homelands.
See Ask MIT Climate: Why do some people call climate change an “existential threat”?