[sfn42]

The problem with carbon capture is volume. There is about 0.04% CO2 in air. So in order to remove a ton of CO2, you would need to process thousands of tons of air, depending on the efficiency of the extraction process.

It's just kind of infeasible to pull the entire atmosphere through these plants. The largest one we have is called mammoth, claimed to remove 36000 tons of CO2 per year, meanwhile our emissions are measured in billions of tons per year. Like over 30 billion.

We would need about 30 mammoths to get to a million tons per year, and 30,000 mammoths to get to a billion. Then multiply by another 30 and in total we would need almost a million mommoth plants just to undo what we are doing right now at the same rate. Carbon capture is like trying to empty the ocean with a bucket.

How are you so confident that extinction is off the table? I've stopped following this stuff because it's depressing but last time I checked we were in dire straits and I haven't heard any good news on this front. I'm just seeing ice caps disappearing, ocean currents changing, weather changing, pretty much everything that's been predicted is now happening and it's not going to slow down any time soon.

[myrmidon]

> How are you so confident that extinction is off the table?

Because even the worst-case scenarios (=> think RCP8.5) are just not enough to get rid of us.

I can totally see populous breadbasket states turning into unliveable deserts, billions of deaths from famines and heatwaves, iconic coastal cities being lost to the sea and a giant loss of biodiversity-- but I simply don't see this eradicating our species.

Humans are too adaptable, and warming is invariably gonna leave too many survivable holdout regions.

I think that an all-out global nuclear war would be much more threatening to humanity, and even that I'm very confident we would survive as species.

[sfn42]

Yeah so this is mostly just a difference of definition. When I say extinction I mean what you describe, essentially a total collapse of modern society. I don't care whether/how long a few people survive somewhere, your scenario is apocalyptic enough for me to label it an apocalypse.

I also think this process is likely to trigger a new world war. When nations start collapsing there will be two possible outcomes - other nations take them in or they go to war. They won't just sit down and die. And everyone else won't be able to handle the number of refugees even if they want to.

[usrusr]

But what's the probability of those direct climate effects happening without an all out nuclear war on the side, as a second order effect of the climate change? Humans are prone to fall for whatever radical ideology crosses their path when the future looks bleak.

[myrmidon]

I don't believe in world-war as byproduct of climate change yet.

I think capability to wage war internationally will probably decrease thanks to climate change; it is much easier for a state to prevent the peasants from starving than to feed/equip/fuel an army.

I also don't really see the incentives working: Countries like Bangladesh that are gonna suffer disproportionally are mostly not in a position to wage war offensively, and famines/heatwaves are not gonna make it any easier.

My admittedly cynical outlook is that it will just be business as usual: More affected/poor nations struggling, while wealthier western states moan about refugees, use their wealth as buffer and proceed to not care about people dying elsewhere.

[antonvs]

I mostly agree with your assessment, except that "moaning about refugees" and resulting action is going to get a whole lot worse as the numbers increase.

We're already seeing how countries like the UK and US can be manipulated to respond to these situations, even when their effects are mostly imaginary and even net positive. Imagine what will start happening if the bogeyman of migration becomes a real problem.

"Use wealth as a buffer" works in the current scenario to some extent - although the US seems to have a lot of trouble with it. But what will scaling that look like? Trumpian concentration camps throughout the country, ICE budget approaching that of the US military, national curfews, martial law, suspension of habeas corpus...? We've already seen hints of all these things.

Things could get very bad. But I agree, not extinction-level, yet. Give us time though!