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We all agree on the terrible consequences of >2 degrees of warming globally. But knowing that we will almost surely develop technology that can prevent it for a

We all agree on the terrible consequences of >2 degrees of warming globally. But knowing that we will almost surely develop technology that can prevent it for as little as $1 billion to $10 billion per year [1], I can't help but think that situations like you and other alarmists describe will never be true. However experimental, however risky, if this cheap solution exists then surely some countries at some point will use it before it is too late for them. I don't think we will ever see 5 degrees of warming if sun-reflecting particles work, and chances are they do. [1] https://www.nature.com/articles/d41586-018-07533-4 https://www.nature.com/articles/d41586-018-07533-4

graeme 8y ago
But the oceans will turn acid with CO2, and the air we breathe will be different, which some research indicates has lowered nutrients in crops. The ocean is the easiest effect to prove, but then there will be other unknowns of altering the air to have more CO2 and a dimmed sun. You’re awfully cavlier about the one inhabitable planet we have.
- teshier-A 8y ago
  The whole point is that it's not about me being anything, it's about a pretty objective cost-benefit analysis. I agree that there are big unknowns but I don't think that detracts anything from the point I'm making.
  - graeme 8y ago
    We have the option of trying to limit or reverse the changes we've made to our biosphere. If we instead mitigate the main symptom via dimming the sun, we're likely to simply burn all the carbon we can find. But that still leaves us with the other symptoms (ocean acidification) and unknown side effects. So it's not a cost benefit analysis, because it only looks at the known costs. Here the known downside of an acid ocean and the unknown cost of side effects dwarf the actually calculable financial costs. If we could run a thousand earth simulations we could speak of cost benefit analysis. But we just have one, and we know the conditions we grew our civilization in. We may well have to do sun shading regardless, but we shouldn't call it a mere ten billion. Edit: I guess to more properly respond to your original point: things may get very bad even if we do sunshades. Just via other mechanisms. Having the option will likely encourage a much higher co2 level than without sunshades.

graeme 8y ago

But the oceans will turn acid with CO2, and the air we breathe will be different, which some research indicates has lowered nutrients in crops. The ocean is the easiest effect to prove, but then there will be other unknowns of altering the air to have more CO2 and a dimmed sun. You’re awfully cavlier about the one inhabitable planet we have.

teshier-A 8y ago
The whole point is that it's not about me being anything, it's about a pretty objective cost-benefit analysis. I agree that there are big unknowns but I don't think that detracts anything from the point I'm making.
- graeme 8y ago
  We have the option of trying to limit or reverse the changes we've made to our biosphere. If we instead mitigate the main symptom via dimming the sun, we're likely to simply burn all the carbon we can find. But that still leaves us with the other symptoms (ocean acidification) and unknown side effects. So it's not a cost benefit analysis, because it only looks at the known costs. Here the known downside of an acid ocean and the unknown cost of side effects dwarf the actually calculable financial costs. If we could run a thousand earth simulations we could speak of cost benefit analysis. But we just have one, and we know the conditions we grew our civilization in. We may well have to do sun shading regardless, but we shouldn't call it a mere ten billion. Edit: I guess to more properly respond to your original point: things may get very bad even if we do sunshades. Just via other mechanisms. Having the option will likely encourage a much higher co2 level than without sunshades.