this post was submitted on 02 Feb 2024
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Climate - truthful information about climate, related activism and politics.

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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.

Recommended actions to cut greenhouse gas emissions in the near future:

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[–] stabby_cicada@slrpnk.net 9 points 8 months ago* (last edited 8 months ago) (1 children)

Weirdly, I'm not completely opposed to this. Solar sail technology is a promising avenue for interplanetary travel/exploration, and we'd want to test the technology for giant solar sails somewhere near the Earth, so why not?

Besides the fact that "block the sun" is a traditional supervillain master plan, I guess.

[–] silence7@slrpnk.net 16 points 8 months ago* (last edited 8 months ago) (2 children)

A bunch of reasons:

  • as we dump co2 in the atmosphere, much is absorbed in the oceans, acidifying them. This will kill off a big chunk of marine life
  • it's tough, and not particularly likely to succeed at the needed scale
  • we will need to maintain this system for a few hundred thousand years. Humans don't have a track record of maintaining civilization for that long
  • we will end up with substantially different weather patterns due to a reduced pole-to-equator temperature gradient.
[–] sonori 2 points 8 months ago (1 children)
  • This sort of plan is not being proposed as a alternative to carbon reductions. It would take decades to build up the lumar or asteroid based infrastructure at minimum, and thouse manufacturing lines would need to run for decades to build up the array to the point it starts making an impact. It’s a plan that would at best start to have an effect around 2075, and that’s presuming sustained hundreds of billions of dollars investment. If we are not already close to achieving net zero by then, then we never will be.

The point is that it provides a possible pathway to reverse temperatures, and related things like storm intensity, agricultural area, and sea levels, back down to preindustrial levels, hence reducing the sustained human death toll being continually exacted for emissions done generations before. It is living with what was already done, not an excuse to pollute more.

  • It’s difficult, but your unlikely to run into any unexpected problems after you get your first satellites placed beyond thouse that come with scalding up. In raw scale, this is a project on terms with building and maintaining the international highway or rail systems, or for a more topical example the solar buildout we need to do to reach net zero in the first place. Vast yes, but hardly unprecedented.

  • Humans don’t have a track record of failing to do so either. Most civilization collapses are localized, and rather hyperbolic. The collapse of the Roman Empire for example is much closer to the collapse of the British Empire into the modern day UK than the ideas of abandoned long lost cites and technologies pop culture likes to portray it as for instance.

Moreover, unlike a lot of other geoengineering proposals, there are no significant snapback effects from stoping maintenance, just a slow return over fifty to a hundred years to the point you were already at before starting.

  • An L1 array wouldn’t have that drawback from my understanding, and an earth orbital array would allow you to vary the intensity being let through simply by haveing the satellites turn sideways, or enter a slow constant rotation if your worried about RCS system wear. You could also actively plan the luminosity over a given region to destructively interfere with major storm events, once again saving lives on the ground.
[–] silence7@slrpnk.net 1 points 8 months ago (1 children)

This sort of plan is not being proposed as a alternative to carbon reductions.

That was the whole point of introducing solar radiation management into the discourse; creating social permission for the fossil fuels industry to keep on extracting and burning.

[–] sonori 1 points 8 months ago

I feel like if that was the point then the foucus would have been on something that the layperson might think was cheaper and easier than lowering emissions like carbon capture, not something which most people outright reject as impossible like orbital shades and mirrors, which generally come up more in discussions of terraforming Venus and Mars then the context of gobal warming.

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