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A subpolar-focused stratospheric aerosol injection deployment scenario

iopscience.iop.org

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Re: A subpolar-focused stratospheric aerosol injection deployment scenario

#3
Fun fact: we are currently in an ice age. By definition, when ever there is ice sheets covering both poles we are in one.

The default state for earth is no ice over the poles (as far as we can tell)

The amount of ice also fluctuates wildly in an ice age. The ice coverage can be where it’s currently at (poles), all the way to an ice sheet covering half of the US and Europe.

But in the last 5 million years, there’s a cycle where ice sheet size and thickness increases, then decreases at a regular 100k interval. The last few thousand years we’ve been at a lower and decreasing end of ice

https://en.m.wikipedia.org/wiki/Ice_age

The idea that we’d want to put the Earth back into an ice age when (1) that doesn’t appear to be the default for earth and (2) an ice age means less food — it’s an insane idea.

Scarier that any random old country could probably do this without consent of the globe.

Re: A subpolar-focused stratospheric aerosol injection deployment scenario

#4

Fun fact: we are currently in an ice age. By definition, when ever there is ice sheets covering both poles we are in one. The default state for earth is no ice over the poles (as far as we can tell) The amount of ice also fluctuates wildly in an ice age. The ice coverage can be where it’s currently at (poles), all the way to an ice sheet covering half of the US and Europe. But in the last 5 million years, there’s a c…

An ice age also means more arable land, and eventually megafauna. Downside: Everyone has to move into former ocean plains Upside: You will be able to walk to circumnavigate most of the planet

Earth at glacical maximum https://www.cbc.ca/greathumanodyssey/content/assets/images/m...

Re: A subpolar-focused stratospheric aerosol injection deployment scenario

#7

Fun fact: we are currently in an ice age. By definition, when ever there is ice sheets covering both poles we are in one. The default state for earth is no ice over the poles (as far as we can tell) The amount of ice also fluctuates wildly in an ice age. The ice coverage can be where it’s currently at (poles), all the way to an ice sheet covering half of the US and Europe. But in the last 5 million years, there’s a c…

Nowhere in the "Expected climate impacts" section is inducing an ice age even on the table. The anticipated effect is a 2C cooling of the atmosphere. Considering we're on track to blow way past a 2C increase in atmospheric temperature from 100 years ago to 30 years from now, SAI would be a mitigating action. The goal is to maintain our habitat.

Re: A subpolar-focused stratospheric aerosol injection deployment scenario

#8
- "6.7 Tg-SO2/yr in each hemisphere"

Perspective: that's roughly one Berlin airlift in each hemisphere. (Peak airlift was 12,941 tons/day, which would be 4.7 million tons annualized).

https://en.wikipedia.org/wiki/Berlin_Blockade

I don't know if the approach in the OP is a correct one or not; but it would embarrass the history of our species to argue we're not capable of doing it.

Re: A subpolar-focused stratospheric aerosol injection deployment scenario

#10

I might have missed it, but they don’t seem to talk about the fate and transport of the sulphuric acid that forms when the sulfur dioxide oxidizes. This is important to know.

I find "marine cloud brightening" [0] a lot more interesting. It aims to increase the albedo of Earth by creating more clouds over the oceans e.g. by spraying seawater.

Pro: "If implemented, the cooling effect is expected to be felt rapidly and to be reversible on fairly short time scales.", [0]

[0] https://en.wikipedia.org/wiki/Marine_cloud_brightening

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