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Comment by GOONIMMUNE | Hacker News Reader

How does "leaving it in the ground" get us back to 280 ppm?

It obviously doesn't and they never claimed that it did. The point is that it's cheaper on the margin to stop polluting than it is to keep polluting and then clean it up afterwards.

Imagine a boat filling with water, you would want to plug the whole before you start bailing out water

Imagine the first hole has been leaking for 200 years, and also getting a new hole each year. Also each hole grows every year. The boat is on track to be totally sunk in a couple decades.

You probably want to start bailing immediately, also start plugging holes immediately. Except our technologies for bailing aren't practical yet (and may never be). If we don't plug the holes, we'll sink. If we don't start bailing, we'll sink. If we do both immediately, we might still sink but we've got a better chance.

Much better to bail out the water without plugging the hole than to do nothing and keep complaining about how no one can successfully plug the hole.

It's not clear to me 280ppm is actually ideal, because below 150ppm, most plant life on Earth begins to die from the lack of CO2 in the atmosphere. It takes a couple generations for plants to adapt (which they can), but I don't imagine most crops and forests will survive the transition well.

I actually think where we're at is relatively decent. We know what's happening, can reliably predict certain storms.

Definitely don't want to go any higher, but going in the opposite direction for too long is entering ice age status.

The goal shouldn't be to adhere to a specific number, but identify an acceptable range/boundary.

> I actually think where we're at is relatively decent. We know what's happening, can reliably predict certain storms.

You mean aside from the massive wildfires, depleting groundwater with droughts in so many parts of the world, etc.? The status quo hits the 'sweet spot' for you?

Those wildfires are not new, and are more a factor of humans over meddling (putting out every tiny fire instead of letting nature do it's thing). Global warming plays a part but it's not as if nature was without forest fires pre-man.

Likewise droughts are just as much caused by misuse of water resources than they are changes in rainfall. California in particular has no business having cities as large as it does given their groundwater situation - and that has been before global warming accelerated.

California is not the only place on earth dealing with severe ground depletion, droughts, or wildfires.

And it's not like putting the blame somewhere else somehow changes the reality.

The observation I'm making is that we know what the bounded risks are. We don't know what the lower bounds (or upper bounds) might do. We've planted lots of vegetation that depends on the growth of CO2 levels year after year (to some degree). It's not clear to me that if it gets too low that would be a good thing.

By the way, I'm not arguing that we shouldn't decrease the CO2 levels. We should. I'm trying to have a nuanced and interesting discussion about a very complex phenomena.

Each of those problems you brought up can also be mitigated with proper engineering as well.

Take for example how Israel effectively solved the drought problem. Now that's an exceptional case and it wouldn't be logistically feasible to expect every nation to dedicate so much of their GDP to such problems. I'm just trying to suggest there are other variables at play, besides moving CO2 levels up and down like a thermometer.

There is a substantial time lag between the concentration of carbon changing and the climate reaching its new equilibrium. Even if we stopped emitting carbon today the warming would continue for some time. So if you're OK with what it's like today then you still need to take some carbon out of the atmosphere to keep it like this.

Yes I agree with you.

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