posted this video on the old forum, but I feel it may be worth reposting it here
Once concern here is that the projections presented in the video are also science fiction, i.e. based on science in the sense that it can't rule it out. IPCC says on the equilibrium climate sensitivity: "there is
high confidence that ECS is
extremely unlikely less than 1°C and
medium confidence that the ECS is
likely between 1.5°C and 4.5°C and
very unlikely greater than 6°C". "Medium confidence" that it is within a very large range. How can one create a graph like the one in that video based on that?
Anyway, I think "tropical Earth" is survivable. If we had found an exoplanet with that climate, its climate would be perceived as so perfect for human settlement that a lot of people would already begin to plan for it. It's not a matter of whether a human civilisation can exist or not, rather whether we want such changes.
This is the tyranny of procrastination.
Even worse than procrastination is futile, symbolic action, taking resources away from the long term solution. Which is cheap and abundant energy. We do not have that technology yet, but if it exists, it pretty certain that it depends on Einstein's equations and we've only taken the first step, fission energy, which we would never have managed to make had it not been for fossil fuel. Other sources of energy, fossil, hydro, wind, solar, tidal, whatever, will have their niches, but shouldn't hinder more revolutionary progress. Even without climate scares we need that abundant energy.
More on the Karl paper controversy.