It's quite in-depth and allows tweaking many different factors and assumptions, and it also shows many different charts. Some general takeaways from playing with the calculator which were surprising for me and might be worth discussing:
1. Reducing deforestation does very little to help reduce global temperatures by 2100. I know that the default EA position on climate change as of a few years back was "support CoolEarth because Doing Good Better said it was cost-effective", and I'm not sure how it's changed since. But it seems worth pointing out that the overall benefit from reducing deforestation (and also planing more trees ala afforestation) seems likely to have a very low upper-bound on its benefit.
2. Carbon capture technologies, in the most optimistic case, does help, but reducing emissions via carbon taxing/pricing still plays a bigger role. I'd previously prioritized such research because it seems like one of the few ways we can go carbon-negative. However, it seems like this simulation assumes we can't scale up the tech fast enough to bring us back to 2010 temperatures, even with the most optimistic settings the simulation allows.
(I note being confused by this because of previous conversations with people who have mentioned that other types of geoengineering interventions like injecting sulfate aerosols into the atmosphere to help with global cooling could be easily deployed, and I don't think the model accounts for these sorts of strategies.)
3. As a result of 2., it seems that policies which price carbon higher seem like one of the highest things to prioritize, if you believe their models for how this changes our energy consumption profile (e.g. shifting from coal to renewables, etc. etc.)
4. Techno-optimism is likely overoptimistic. Even in the best-best-case scenario, where we institute the heaviest carbon pricing strategy, assume maximum research into more efficient fuels, assume heavy subsidies and taxes for clean/dirty energy, and assume maximum energy efficiency and electrification across all sectors, e.g. the techno-utopia scenario, we're still looking at 2C of warming by 2100.
5. Decreasing population growth by itself has a very small impact, which renders arguments like these quite weak. (Of course, there are also other moral concerns regarding efforts to reduce population growth, but I'm just pointing out that the proponents lose, even on their own grounds.)
6. Costs for adaptation are unaddressed. If we admit that it looks very, very difficult to get emissions down to where they need to be by 2100, then if we want to maintain the same standards of living, plausibly next thing to look into is ways of living which can deal with hotter surface temperatures, e.g. living underground. I'm unsure what the research for that looks like, or who's been working on this.
Overall, I think this is a fantastic tool that embodies a lot of the EA values, that's coming from a non-EA source. I think other EA issues could benefit from a similar sort of calculator. For other people who were confused about the scale of different interventions, I hope this proves to be a valuable aid.