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Putting aside "a space-based solar sunshade represents a technological leap forward and would be really cool" -- which I think speaks to me on an emotional level -- I do think this might be the single most powerful technological weapon we have to combat climate change. My reasoning: * people talk about going carbon neutral: great! But this isn't one problem, this is a thousand distinct problems. Our civilization is built on fossil fuels, and every manufacturing process, agricultural process, transportation process, etc, has to be re-invented to not be built on fossil fuels. Progress will never be as fast as we'd like on this front. We can and should push to get there (there is no good path but forward), but every new bit of news we hear out of Antarctica or Greenland should tell you that we need a longer runway. * people talk about carbon sequestration: scaling up carbon sequestration is hard -- IMO, even with uncertainty, it feels a lot harder than blocking 1% of sunlight. There is a (semi)plausible technological path to the latter, at least. We will obviously have to keep exploring carbon sequestration in the hopes that a silver bullet emerges. But we can't count on nonexistent tech bailing us out. That's magical thinking, and one step above "thoughts and prayers". There has to be a plan in the mean time, and that plan needs to scale. We're probably going to need it. * geoengineering with aerosols isn't just geo-engineering, it's essentially terraforming. That's a wing and a prayer, and at the scale we'd need to do it to have an impact we'd surely create some nasty unintentional consequences. * Note: the above is an important risk calculation, because if you're ok with dumping a crapton of aerosols in the atmosphere -- as some people seem to be -- aren't we basically fine on climate already? Just do that indefinitely! Seems fine, right? * if aerosol spam is not fine, your backup plan can only be something in space: you are here, at this pdf, at the solar sunshade. The sunshade has side effects, but they're much more palatable in my estimation -- the 1% of sunlight blocked will have the effect of making every day seem imperceptibly hazier (this was something I noticed during the 2017 solar eclipse at 50% of the sun being blocked -- seemed like a hazy day at that level of diminished sunlight. That was 50%. With the sunshade we're talking a 1% reduction to reduce the global temp by 2C.) Anyway, just my 2c... |