This is probably mostly a proxy for "climate threats are the most top of mind issue for global leaders" due to the recent rise in coverage.
EDIT: I wish downvoters would take the time to share their point of view.
Keep in mind that earth cannot get worse than the last time all CO2 was in the atmosphere. Trees are younger than sharks. There was plenty of life when all CO2 was free. Somewhere in that environment will be space for life like the last time. Sharks and trees and many other animals and plants made it though that environment. And somewhere in that environment, there will be some space for humans because we will be adaptable.
Instead, the biggest threat is AI. It's the new nuclear race. It will come as fast as human possible and it will have access to the most powerful weapons since any participant in that race will need that move to protect themselves.
Unlike CO2, AI will add something to the system that wasn't there before. Its power will be unmatched and unlike humans, it won't miss any lost life-form.
That's optimistic. Climate change is potentially reversible, but it would involve large-scale geoengineering or carbon capture that we don't have the technology for yet.
Developing and deploying that currently-nonexistent technology requires a stable, organized society. It's plausible that climate change could cause the breakdown of organized society before we're able to develop technology to reverse it.
Since bacteria is digesting cellulose this time, we can't rely on earth to fold over old wood. Instead, humans will have to manage the storage. But that should be doable, given the speed with which we can harvest forests.
But there's some tree that grows like a freaking weed and is amazing for carbon sequestration.
I feel like even having 'more' trees again would be helpful; where my family grew up, over the years all the big/old trees that were in people's yards were never replaced as they went away.
Also: carbon nano tubes and carbon fiber. We will build skyscrapers from carbon. There won't be enough carbon available for all the stuff we want to build.
Are you not aware of climate science or even basic astronomy? As the sun grows older and gets closer to the end of its live span it grows stronger and outputs more heat. The growth in solar irradiance happens over the course of millions of years with some lows and highs in the short term (we currently have an insane increase in global temperatures despite slightly lower solar activity compared to a hundred years ago but compared to 10-100 million years ago the sun is significantly stronger). CO2 that is emitted today has a much greater greenhouse effect than CO2 that had been emitted millions of years ago.
Global heating is worse.
Nuclear has a worse worst case scenario. But global warming is worse because it's not a hypothetical threat, it's something that is already happening.
Nuclear threat could be (and was) resolved with common sense, but the time to resolve global warming with common sense was 30 years ago. Now our best outcome is to mitigate its effects. In the best case scenario millions will die. Mass migrations and wars are likely to happen. Recent data even say that we might have underestimated the risk.
> Climate change is reversible in a couple hundred years [...] At worst many people will die but not the entire earth will be inhabitable.
The planet will be fine, our civilisation might not be.
Also, it’s not just about CO2 that’s just one piece of it. There’s also other gasses, like methane f.ex, to be concerned about. Besides gasses there are things like ice , water and cloud reflectivity.
A disturbing corollary: the same challenge of processing an abstraction exists amongst most non-experts who accept AGW (and I'm among them). Hence symbolic gestures (banning straws), conflation with other sacred-cow political issues (corporate capitalism), belief in looming extinction (unlikely; the threat is to civilization, not homo sapiens), all generally filtered through a "purity" moral matrix (to put it in Haidt-ian terms).
As the complex reality becomes filtered through moralizing and politicizing, the other side digs in their heels for predictable tribalist and game-theoretic reasons. It's a truly wicked problem.
[0]: https://www.newyorker.com/magazine/1966/11/12/how-about-a-li...
Even if you think the whole thing is a scam you see that having a grand mission to invest in modern technology is an incredibly effective jobs program just like sending people to the moon. Nobody has gone to the moon again but we still benefit from all the research from that era.
Meanwhile, France has consistently had around half the per-capita CO2 emissions as Germany due to not giving in to the fearmongering over nuclear power.
It's absurd that this incredible progress is held back by the fear of losing 20k coal jobs when the reality is that those 20k coal jobs prevented the creation of hundreds of thousands in the renewable energy sector.
It's true that preserving jobs is a terrible justification for keeping coal around. But similarly "it takes a lot more green jobs to produce the same amount of energy" is not good; it is bad. We should switch to cleaner energy despite that, not because of it.
Saying "existential risk" again and again does not make it true. Hearing it again and again does not make a rational person believe it.
The semantic game of whether it's "human extinction" or "the end of organized large-scale human civilization" is stupid and grasping at straws.
If you take that view, then practically everything is an "existential threat". Wars have been triggered by soccer games...
As for whether "existential threat" means "human extinction" - well what else would "existential" refer to other than human existence?
Again, if you broaden this, then practically anything could be an "existential threat" - to democracy, say. And it's pretty clear that the people screaming "existential threat" intend for people to take it as meaning human existinction - the naive people at least.
Avoiding human extinction from climate change is very easy but with this attitude you're not doing a good job at avoiding that fate. Right now I don't have much faith that humanity won't try to burn every single last drop of oil or chunk of coal. Although it should be very difficult to reach insane targets like 9°C warming it is definitively possible with enough ignorance and dedication and as humanity has shown we have an unlimited supply of these two qualities.
I'm all for zero carbon emissions but the ridiculous "everyone is going to die due to climate change" is pure FUD.
That is an extinction level event greater than the Permian mass extinction.
Probably won't happen, probably not a great idea to push things to see how far we can let things go before it's catastrophic, though.
With a 9 degree temperature increase a large amount of the planet simply becomes uninhabitable during the summer, period.
low, but existing, possibility*
> Saying "existential risk" again and again does not make it true.
Existential risk includes more than extinction, it could also mean society collapses and takes 100 years to recover to current level, or 1000, or 10,000, or _never_ recovers. Maybe some societies collapse but others just turn into deserts. Maybe there is a recovery, but we'll never have the global trade networks of today, maybe we'll never send a man to Mars. It might mean 90% of the population is lost.
I've said nothing about the probability of any of that, but it goes up the slower we act.
1. Intentional or accidental development of a biological weapon that would wipe out the human race.
2. Asteroid strike sufficient for same.
3. Nuclear war, same.
4. Takeover and eventual decimation by AI of some form.
5. Reproductive failure (think falling sperm counts).
6. Failure to thrive, as a species.
I also think that a stance approaching religious fervor is entirely inappropriate for this sort of policy discussion.
(As a wild guess, I think some combination of #4 and #6 is our biggest risk for extinction over the next 10,000 years.)