Meh... 8.5 billion almost guarantees that it would take something just shy of the planet disintegrating into a new asteroid belt around the sun to get rid of everyone.
More likely, there will be upsets in the constructs of civility as we know it, part of which will be population correction event(s). Whether that comes in instantaneous calamities or generationally, it's forced one way or the other. Some remain though.
Ironically, this whole disclosure phenom sweeping society has this huge abstraction of "ontological shock" - talk hyperbole! geesh. But, ironically ... probably it won't be about technology that's been hidden from the machinery of civility since 1947... like harnessing 0 point/quantum blizzum blazzum, or gravity propulsion... whatever the fuck I suppose it isn't impossible.
No, no more likely any real ontological shock over the next while is going to come for the vast majority that couldn't or would believe it, now ... can't believe they are actually dying because of decades of impudence to the crisis.
Anyway, if the 0 point bs and anti grav is true... that would help save this thing. problem is, the Earth has not caught up yet... Even if we immediately stopped adding and forcing,... the apex of the crisis is calculated geo-physically to be still out there decades off. There needs to be a offset/correction plan. Otherwise, the temp will continue to rise faster than species adaptation rates, and humanity is betting its future on hope.
Heh, you know ... our species figuratively sold our souls to tech ... now, it appears tech is going to have to save our souls.