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Comment by fortytwo79 | Hacker News Reader

Okay, now someone needs to do the same study with innocuous end game scenarios. (I know this study links to one other paper that makes this case, but I can't access it, and the abstract has a biased tone)

If you're going to explore worst-case, so you can think through preparedness, then you should also consider the trivial case to make sure we aren't over-responsive either.

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> As noted by the Intergovernmental Panel on Climate Change (IPCC), there have been few quantitative estimates of global aggregate impacts from warming of 3°Cor above (1). Text mining of IPCC reports similarly found that coverage of temperature rises of 3°C or higher is underrepresented relative to their likelihood (2). Text-mining analysis also suggests that over time the coverage of IPCC reports has shifted towards temperature rise of 2°C and below https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/202.... Research has focused on the impacts of1.5°Cand2°C, and studies of how climate impacts could cascade or trigger larger crises are sparse.

The thing to study besides worst base scenarios isn't "best case scenarios" but average case scenarios. And average case scenarios look so bad that it's obvious we are massively under-responsive to this. The "best" people have done in thirty years is reduce the increase in the rate at which CO2 in being released.

Realistically it would take a supervolcano or major asteroid impact to achieve such low-end radiative forcing scenarios, by injecting large volumes of material into the stratosphere and reflecting incoming sunlight, but any such event would be truly immediately catastrophic to human civilization (for example some major Yellowstone eruptions blanketed something like a quarter of continental North America with a meter of ash, IIRC), and would cause major crop failures and global starvation on an unimaginable scale. That would be worse for human civilization than any projected warming over the next century. Also, once the dust eventually cleared, the atmospheric CO2 levels wouldn't have changed much, so warming would continue (for about 100 years until temperatures equilibrated, assuming human civilization was basically destroyed and no more fossil emissions were taking place).

Case example: the Pinatubo explosion (1991) resulted in a bit less than a decade of steady temperatures, as predicted by climate models at the time:

https://pubmed.ncbi.nlm.nih.gov/11976452/

I suppose if we had a Pinatubo every ~5 years for the next 100 years it would result in the lowest plausible warming scenario, without destroying global agriculture.

I’m in. How can we make this happen?

Read Termination Shock by Neal Stephenson

We have a ton of evidence that the catastrophic outcomes are more likely than the innocuous outcomes, so “equally weighting” their likelihood and commissioning research on that basis seems misguided.

It will be tough to get buy-in on that proposition, because many people view this as a Pascal's-wager scenario, with belief in catastrophe being the rational wager.

And then there are people who don’t think the mass extinction and mass immigration that have already happened are a catastrophe.

So what you're saying is that if we're all discussing the potential for catastrophe and it's already happened, then why publish this paper?

I think it's still worth discussing the likelihoods and severities of future catastrophes.

The paper defines what it considers a catastrophe quite well, you should read it! As a climatologist I always appreciate more investigation into the possibilities of future climate, even those I consider unlikely.

What I did say is that a lot of bad effects are already happening. Talking about climate science used to be like being the mythical Cassandra. But now it’s worse: the mass deaths and migration has already begun, and people still deny the evidence all around them that the predictions have already come true.

If there was an industrial accident where a chemical got released and a million people around the factory all died, that would be a catastrophe, right? Okay, a million people scattered around the world die from air pollution every year. Does the point source make it somehow a bigger tragedy in the first example? Yes, I know that without energy even more people would die, but a million deaths that we have all the technology to avoid is still a catastrophe. Regional famines leading to civil war and migration have already happened. Heat deaths in the thousands in Europe this year. Maybe I’m weird that my threshold for catastrophe is so low.

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