[JumpCrisscross]

> It is 100% an existential threat, but the existential bit happens in 100 years

No, it’s not, and no, we don’t know that. Humans will survive climate change. Rich countries will survive, too.

We will all suffer. Economically, healthwise and aesthetically. But that’s not existential. Framing it as such is disingenuous and counterproductive.

[simmerup]

RCP8.5 is pretty much ruled out by people as unlikely for some reason, even as we have the major super power on the planet pulling out of the Paris agreement on climate change.

There is clearly a temperature at which this planet will not support human life, and we could definitely get the planet to that temperature if we don't change course and reach net zero.

Saying its not an existential threat is just wild to me.

[ben_w]

> There is clearly a temperature at which this planet will not support human life

Yes, but that temperature isn't going to be reached by fossil fuels.*

The reduced brain function from the extra CO2 (if we burned all of it) may make us unable to adapt to the higher temperature, however.

* Ironically, unbounded growth of PV to tile all Earth's deserts could also raise the planet's temperature by 4 K or so, and 6 K or so if tiling all non-farm land.

Deserts are huge, this by itself would represent an enormous increase in global electricity supply; but also, current growth trends for PV have been approximately exponential (in the actual maths sense not just "fast") for decades now, so this could happen in as little as 35 years give or take a few (both scenarios are within the same margin for error, because exponential is like that).

[JumpCrisscross]

> There is clearly a temperature at which this planet will not support human life, and we could definitely get the planet to that temperature

There is such a temperature. We are not getting to it in half a century at current emission rates, even with zero curtailment. If you have a source that shows the opposite, I’d be happy to read it.

[simmerup]

Of course not in half a century, but it's not like the earth just stops getting hotter after 2100 rolls around.

What about 2200? Humanity at 2300? It's the same planet with the same feedback loops after all.

[JumpCrisscross]

> What about 2200? Humanity at 2300?

You literally said “the existential threat happens in 100 years.”

And to your questions, we don’t know. I’d love to see the data. I’m still sceptical we hit “existential” levels for human survival. That wouldn’t even happen if we went back to dinosaur levels of CO2.

[seanmcdirmid]

We will go from 8 billion humans to maybe 1 or 2 billion humans, but that is probably going to happen either way. Poor countries will be obliterated, rich countries are likely to see tanking living standards. Long term humans go extinct (or are superseded by some sort of singularity successor) and the earth recovers in a few thousand years as if we never existed.

[teamonkey]

Perhaps we should be using ‘apocalyptic threat’ instead?

[JumpCrisscross]

Sure. That’s fair. I still think it’s potentially hyperbolic, but it’s closer to true than false. “Existential threat” is just plain wrong.