this post was submitted on 20 Dec 2023
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Discussion of climate, how it is changing, activism around that, the politics, and the energy systems change we need in order to stabilize things.

As a starting point, the burning of fossil fuels, and to a lesser extent deforestation and release of methane are responsible for the warming in recent decades: Graph of temperature as observed with significant warming, and simulated without added greenhouse gases and other anthropogentic changes, which shows no significant warming

How much each change to the atmosphere has warmed the world: IPCC AR6 Figure 2 - Thee bar charts: first chart: how much each gas has warmed the world. About 1C of total warming. Second chart: about 1.5C of total warming from well-mixed greenhouse gases, offset by 0.4C of cooling from aerosols and negligible influence from changes to solar output, volcanoes, and internal variability. Third chart: about 1.25C of warming from CO2, 0.5C from methane, and a bunch more in small quantities from other gases. About 0.5C of cooling with large error bars from SO2.

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These scientists want to put a massive 'sunshade' in orbit to help fight climate change (www.space.com)
submitted 11 months ago by [email protected] to c/[email protected]
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[–] [email protected] 28 points 11 months ago (2 children)

The big problem with a sunshade is that it would be an engineering project on a scale that we have never seen, and we're not really entirely sure it would work. It would cost at least $10 trillion USD and require launching nearly 200 billion small vessels and moving them into the L1 Lagrange point between us and the Sun. Each vessel would have a shade that covers 2500 m^2 with a total mass of ships and shades being 34 billion metric tonnes.

A sunshade just isn't feasible and all of those rocket launches to get it into position would just exacerbate the already pretty awful situation here on Earth, not to mention mining all of that material and building the rockets causing greenhouse gas emissions, and is there even 34 billion metric tonnes of material on Earth with which to make effective sunshades out of?

It would be a MASSIVE, MAAAASSIIIIIVE undertaking the scale of which Humanity has never seen to get it done, and we're not even sure if it would work. We're much better off focusing on solutions here on Earth, I think.

For those curious, here's a scientific paper looking into the subject that I used for reference on the numbers I used: https://www.sciencedirect.com/science/article/pii/S0094576521001995

[–] [email protected] 14 points 11 months ago

Above and beyond what you've said: we would need to maintain that sunshade for hundreds of thousands of years.

Civilizations don't tend to last that long. The odds of our being able to actually maintain technical infrastructure like that for the required amount of time are low.

[–] set_secret 10 points 11 months ago

immediately transitioning to zero emission and planting a shit tonne of trees would probs be cheaper.