[Mithaldu]

I'd like to answer, but you didn't ask an actual question, so i'll take a blind stab.

Short version: CO2 causes general warming. Ice caps on the pole are necessary to keep the planet cool by reflecting a lot of the incoming light. General warming will cause ice caps to melt, which causes more energy from the sun to be absorbed, which causes even faster warming. Permafrost areas will also thaw, releasing CO2 and methane, resulting in even more warming. Strong heat increases can damage rain forests, reducing the CO2 absorption, also speeding up warming. Result: Best case scenario: Loss of coastal regions to sea rise. Worst case scenario: Earth becomes a second Venus.

Edit: To downvoters: If i got facts wrong, please do correct me. The above is my understanding of the sitation and i may have gotten some wrong.

[themckman]

> > assured doom

> This part of your statement is actually a little bit of the problem here, too. Can you define more clearly what you mean by this?

That was my question. I appreciate your summary of the situation and I think your worst case assessment answers my question. Unfortunately, there's an incredibly huge gap between "loss of coastal regions" and "Earth becomes a second Venus". One situation sounds highly surmountable while the other sounds like the certain extinction of our species. When you use phrases like "assured doom", I tend to think of outcomes more like the latter and I find that type of rhetoric almost as unhelpful as denying the whole situation. It just doesn't help anyone.

I apologize for picking on you specifically, you're just the first one to express this kind of sentiment I came across.

[tremon]

Unfortunately, there's an incredibly huge gap between "loss of coastal regions" and "Earth becomes a second Venus"

And you are basing this on what, exactly? Because the answer right now to that question is "we don't know how huge that gap is". And we do not have a second Earth to test your theories on. Are you really willing to take the risk of assured doom based on your belief that "the gap between now and assured doom is incredibly huge"?

Here's the thing with dynamic equilibrium: it is only locally stable. We do not know how exactly how resilient our ecosystem or our planet is to rapid changes. Some of us are not willing to find out, because we only have a single destructive test at our disposal.

[themckman]

> And you are basing this on what, exactly?

I made that statement based on my limited ability to extrapolate how our species might deal with the two scenarios. It sounds much, much easier to me, while still being incredibly challenging, to deal with large population displacement versus dealing with our planet becoming entirely uninhabitable.

Now, if I understand what you're saying, it sounds like our understanding of the probabilities of the two scenarios occurring isn't exactly known. While the two scenarios, at face value, sound incredibly different (to me at least), the likelihood of one happening over the other could be very similar. I agree that we should absolutely take that position seriously and that we should absolutely do things to guard against the possible outcome where our planet becomes uninhabitable.

All that I'm asking is that we say it like that. Lets say that instead of speaking in absolutes (e.g. "its a hoax", "we're doomed"). That's all I'm taking issue with. It doesn't help the discussion no matter what side of the argument those kinds of statements come from.

> And we do not have a second Earth to test your theories on. Are you really willing to take the risk of assured doom based on your belief that "the gap between now and assured doom is incredibly huge"?

To be clear, I don't have any theories I'd like to test nor do I know what I might be willing to risk. As I said in my original comment, my understanding of everything is incredibly rudimentary and I'm trying to do a better job seeking information to help me answer questions like that.

[Mithaldu]

> if I understand what you're saying, it sounds like our understanding of the probabilities of the two scenarios occurring isn't exactly known

Incorrect.

A complete planet-devastating runaway scenario is much more likely, as it requires merely that humans continue to operate as they are doing right this very moment.

The best case scenario only comes about if we get our shit together.

That's the gap that separates worst and best case: Humans change nothing <---> Humans make a supreme effort. Probabilities follow directly from the probabilities of these two things.

Sorry for not having stated that clearly.

[tremon]

Now, if I understand what you're saying, it sounds like our understanding of the probabilities of the two scenarios occurring isn't exactly known

No, what I'm saying is that we don't even know whether these really are two separate scenarios. We can't afford to plan for a large population displacement because by the time we get to that point, there may be nothing we can do to prevent our planet from becoming uninhabitable.

[anon1253]

'Unfortunately, there's an incredibly huge gap between "loss of coastal regions" and "Earth becomes a second Venus"' … maybe there's not. And that's part of the problem. Psychologically people perceive differences as "linear". It's part of how our brains are wired: to go from A to B draw a mental line and try to walk it at a constant speed. The greater the difference, the longer the line, thus the longer it takes to get from A to B. Hence the "huge gap" sentiment. But climate is not a linear system. Going from A to B could be a tiny step. Or oscillating, or dampening, or all sorts of funny things. Modelling of, for example, oceanic plankton (which gives more than 50% of the atmospheric oxygen) showed that the difference between "happy ~20% oxygen in the atmosphere" to "no oxygen ever again" is a small temperature change [1,2]. Non-linear systems are very hard. But they are fact, not fiction. That one last metric ton of CO2 could really be the difference between "life as usual" and "goodbye complex life on Earth". Communicating that fact is unfortunately even harder. Because people cannot perceive these changes, they're stuck in the linear mindset. And this worries me, because when we realize we need to really do something it's probably already far too late. If it isn't already (but in that case, science won't matter…I'd rather turn the page to "existential philosophy in the face of extinction").

To me it seems like simple risk management, even with a small probability the loss would be near infinite, whereas the loss of "doing something" is probably negligible. (carbon tax, energy transition, discouraging procreation, anti-consumerist lifestyle … probably all beneficial for humanity from a birds-eye view)

[1] http://www.wolfandwildlifestudies.com/downloads/oxygendeplet...

[2] https://link.springer.com/article/10.1007/s11538-015-0126-0

[Mithaldu]

In a way i can understand you, in another way: Consider what "the entirety of Florida, New York and California is forced to move inland" will mean in practice. Then consider what the same would mean for less affluent countries.