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Covering just 20% of the Sahara with solar panels causes a 1.5 C increase in global temperatures. Solar panels are dark, and dark absorbs heat. Solar panels ar

by pests 3y ago

Covering just 20% of the Sahara with solar panels causes a 1.5 C increase in global temperatures. Solar panels are dark, and dark absorbs heat. Solar panels are what, not even 30% efficient yet? So for every watt generated of useful energy, is two watts of extra heat. Not a problem small scale, definitely something to think about long term. Similar feedback loop to ice sheets melting exposing darker land and ocean beneath. Also explored in the sci-fi book "Project Hail Mary"

deleted 3y ago
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kragen 3y ago
[citation needed] also though if we're talking about such mega-engineering projects you can float them on the ocean, which has a lower albedo than solar panels. or use some of the energy to make a lot of white plastic netting and drape it over a low-albedo region
- pests 3y ago
  https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL090789 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/202... Don't quote me on the exact numbers, I wrote my original post from memory of an article summarizing the above paper but I never read the actual paper and do not know the accuracy of the claims.
  - kragen 3y ago
    thanks, this is great! it looks like the effects are complex enough that you could probably have the opposite effect just by choosing a different desert; it's not just a simple additive thermal forcing model as i was assuming
Workaccount2 3y ago
I like how you frame "covering 20% of the Sahara" as a "just". Like it would be some trivial feat easily accomplished. For reference, 20% of the Sahara is around the size of Mexico.
- pests 3y ago
  That comes straight from an article[0] I do admit I do not know if it accurately quotes its source but it was not just a made up example. It is also relevent to the story of Project Hail Mary by Andy Weir (2021) where they needed 2 trillion square meters of solar panels for an emergency. The study quoted in the article below was in 2018, book released in 2021, the article itself in 2021, might be some covergent evolution to the story. [0] https://theconversation.com/solar-panels-in-sahara-could-boost-renewable-energy-but-damage-the-global-climate-heres-why-153992 https://theconversation.com/solar-panels-in-sahara-could-boo...

by pests 3y ago

deleted 3y ago

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kragen 3y ago

[citation needed] also though if we're talking about such mega-engineering projects you can float them on the ocean, which has a lower albedo than solar panels. or use some of the energy to make a lot of white plastic netting and drape it over a low-albedo region

pests 3y ago
https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/2020GL090789 https://agupubs.onlinelibrary.wiley.com/doi/full/10.1029/202... Don't quote me on the exact numbers, I wrote my original post from memory of an article summarizing the above paper but I never read the actual paper and do not know the accuracy of the claims.
- kragen 3y ago
  thanks, this is great! it looks like the effects are complex enough that you could probably have the opposite effect just by choosing a different desert; it's not just a simple additive thermal forcing model as i was assuming

Workaccount2 3y ago

I like how you frame "covering 20% of the Sahara" as a "just". Like it would be some trivial feat easily accomplished. For reference, 20% of the Sahara is around the size of Mexico.

pests 3y ago
That comes straight from an article[0] I do admit I do not know if it accurately quotes its source but it was not just a made up example. It is also relevent to the story of Project Hail Mary by Andy Weir (2021) where they needed 2 trillion square meters of solar panels for an emergency. The study quoted in the article below was in 2018, book released in 2021, the article itself in 2021, might be some covergent evolution to the story. [0] https://theconversation.com/solar-panels-in-sahara-could-boost-renewable-energy-but-damage-the-global-climate-heres-why-153992 https://theconversation.com/solar-panels-in-sahara-could-boo...