So, what does this have to do with the Earth again?
Humanity may very well be F**ked as described, but that's not the same thing as the Earth. Realistically speaking, we are not going to destroy the entire biosphere. As some of the commentators on that site pointed out, the planet will continue just fine without us. Just another mass extinction.
Of course, some people may consider the fate of humanity and the fate of the Earth to be the same thing, but that's merely hubris.
It's just shorthand. Obviously
, this planet is going to go on, whether we're here or not, probably until the Sun swells up and swallows it in a few billion years.
"The world," as far as we're concerned, doesn't exist if we are all dead.