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True human extinction doesn't seem plausible, but in a worst-case scenario we can imagine a > 99% drop in population, roughly to what is sustainable without tec

True human extinction doesn't seem plausible, but in a worst-case scenario we can imagine a > 99% drop in population, roughly to what is sustainable without technology, in a dramatically harsher world. ("Without"? Well, nobody today knows how to build a cast-iron plough.) I don't believe this scenario is likely. For one thing we're not headed for 8C of heating; for another, technological change seems to be coming just in time to head off the very worst outcomes, assuming we struggle hard enough.

vkou 4y ago
> assuming we struggle hard enough. We aren't struggling at all, though. We just eased off the accelerator a little. (Assuming that our accounting is correct, and that methane leakage isn't worse than we think. [1]) [1] It's worse than we think.
- Filligree 4y ago
  True, but... I need to retain some optimism, or I get too depressed to keep on. In this case, my optimism is that solar/wind and batteries will drop enough in price that fossil fuels become economically unfeasible. It seems possible! I just hope it isn't too little, too late.
skyfaller 4y ago
We probably aren't headed for 8 degrees of heating, based on what we know today. There are a lot of "out there" scenarios that don't make it into sober, conservative scientific reports from the IPCC, because they recognize how important it is that people take their warnings seriously, and they don't want to mention anything they don't have very clear evidence for already. One of my "favorites" is the "world without clouds" scenario, which for the record, I consider unlikely, but is horrifying to imagine: https://www.quantamagazine.org/cloud-loss-could-add-8-degrees-to-global-warming-20190225/ https://www.quantamagazine.org/cloud-loss-could-add-8-degree... What we're dealing with are "unknown unknowns": what tipping points might exist that we don't know about, that might result in more warming faster than expected based on today's science? We shouldn't take those kind of existential risks.

vkou 4y ago

> assuming we struggle hard enough. We aren't struggling at all, though. We just eased off the accelerator a little. (Assuming that our accounting is correct, and that methane leakage isn't worse than we think. [1]) [1] It's worse than we think.

Filligree 4y ago
True, but... I need to retain some optimism, or I get too depressed to keep on. In this case, my optimism is that solar/wind and batteries will drop enough in price that fossil fuels become economically unfeasible. It seems possible! I just hope it isn't too little, too late.

skyfaller 4y ago

We probably aren't headed for 8 degrees of heating, based on what we know today. There are a lot of "out there" scenarios that don't make it into sober, conservative scientific reports from the IPCC, because they recognize how important it is that people take their warnings seriously, and they don't want to mention anything they don't have very clear evidence for already. One of my "favorites" is the "world without clouds" scenario, which for the record, I consider unlikely, but is horrifying to imagine: https://www.quantamagazine.org/cloud-loss-could-add-8-degrees-to-global-warming-20190225/ https://www.quantamagazine.org/cloud-loss-could-add-8-degree... What we're dealing with are "unknown unknowns": what tipping points might exist that we don't know about, that might result in more warming faster than expected based on today's science? We shouldn't take those kind of existential risks.