Hi John, thanks for the reply, I wasn't expecting one after this long but I am pleased about the thoroughness and thought you put into it.
Yes, I think it's likely to be catastrophic (not extinction risk). If your assertion that it is only likely to be used when warming is 4C+, your whole argument is moot because that is already past the point of no return. From the base that 4C+ is an unacceptable situation, you would immediately be making the case that SG should be funded and accelerated by your own following argument - that currently policy and resear
Cloud formation was the biggest unknown feedback loop and efforts to model them more accurately has led to the increase in range. The effects only start at unprecedented levels of warming which is why observational data may not fit.
I have tried to lay out in the section on probability, above, that most X-risks are a subset of C-risks as they collapse usually has to happen before an existential event. Most X-risks in their moderate form, such as a nuclear winter lasting a few years, moderate climate change, or a global pandemic seem much more likely to pose a C-risk than an X-risk.
Thanks for the comment! I am aware about the GCRI and GCRs but I don't see the term getting used much and (in both cases) seem to get conflated with X-risks, but I haven't addressed this at all in the piece so I will add an edit.
Thanks for catching the typo. I've been trying to embed the images but it hasn't been working, so I'm contacting support for help.
The analogy I was making was that socially held values are liable to change and (usually) improve over time, and any specific value might not disqualify a future civilisation from being counted as valuab
This doesn't seem to be the context in which you were dropping the link, seeing as they all have top-level summary numbers that feed into your boundaries and point 1 doesn't say anything about 2m/year being a lower bound, seeing as you are using it as the upper bound. I would like to see these other estimates of climate mortality as they aren't referenced or seem to feed into point 1.
On a meta-level I think disconnecting sources with the context with which you are referencing them is very unfriendly to the reader as they have to wade through... (read more)
I think when considering your estimates for 1. it is important to consider the boundaries given by those sources and to contextualise them.
The WHO is only looking at disease burden but even there they are expecting 250k to 2050 (not even looking to 2100) and they estimate that CC will exacerbate malnutrition by 3% of current values - this seems extremely conservative. They don't seem to include the range increases for most other insect-transmitted diseases, just malaria, even within the extremely limited subset of causes they consider.
Impactlab'... (read more)
Hi John, thank you for this piece. I know it's been a long time since you posted this but I wanted to respond to some of your thoughts.
"In my view, solar geoengineering is only likely to be used once warming is quite extreme, roughly exceeding around 4 degrees" - +4C is already endgame and catastrophic in my opinion. Considering that most of the heat is being absorbed by oceans leading to acidification, we'll already be seeing significant sequestration losses as marine animals are unable to build calcium carbonate shells.
"This sug... (read more)
I do not disagree that the Vice piece and the think tank research are likely alarmist and unrepresentative, but unfortunately in my opinion John Halstead's analysis and the underlying IPCC reports are entirely too optimistic on the flipside. I think this leaves a lot of room for further serious evaluation of the potential existential risks on climate change.
Firstly, John Halstead's review of existing literature. I was privileged enough to go to his talk EA Global London 2018 which was a summary of this work. It is a very large and understudied fi... (read more)