Unless we modify the stratosphere, Earth will be uninhabitable for most people and many species by 2050. We need to start now, and we need to be *even more* cavalier than we’ve been with modifying the atmosphere.
No centralized institution is going to move quickly enough to do this: it’s got to be a rogue actor. Probably a startup. Should we fail to act, nuclear ware with the excuse of geoengineering (I mean… technically it is) is likely to occur.
Why sulfur dioxide injection? We know it works: volcanoes do it, and Pinatubo cooled the world by .5C for a year. It’s temporary: 1-3 years and it settles back to Earth. It’s affordable: offsetting all temperature gain from the Industrial age would likely cost <$10B per year, including delivery charges to stratosphere;)
Why put sulfur dioxide in the stratosphere? Things in the troposphere (<6-20km) settle back to earth too quickly, and it’s too hard to get a tethered tube up to the mesosphere (or further). We should start testing higher asap, too:)
Why tethered? This is by far the cheapest way to modify the stratosphere per ton delivered, and development costs are reasonable. Also, it’s the only method for which I can think of clear monetization srategies. Sucks to have to consider that, but we live in the world we’re given. Sucks to have to geoengineer the stratosphere, but we’ve so fucked the troposphere that we don’t really have any other choice.