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Agreed. The biggest point that seemed missing to me: the author talked so much about increased evaporation, but isn't water vapor one of the worst greenhouse g

Agreed. The biggest point that seemed missing to me: the author talked so much about increased evaporation, but isn't water vapor one of the worst greenhouse gases? Sure you mitigate sea level rise, but at the cost of increasing temperatures? That doesn't seem like a great tradeoff.

bonzini 3y ago
The water just moves, doesn't it? He's saying to build a canal.
- coryfklein 3y ago
  I guess it depends on whether such canals increase the net surface area. If you raise the ocean by 3mm across the globe, does it result in the same net increase in surface area as flooding a large swath of the Sahara?
snewman 3y ago
You are correct that water vapor is the primary greenhouse gas. Despite that, water vapor emissions are not generally considered to impact warming. I think that is because the water content of the atmosphere is already in balance due to the massive amount of evaporation and condensation (e.g. rain) that is constantly going on. If we dump some extra water vapor into the atmosphere, that will balance out as a bit of extra rain and/or a bit less evaporation somewhere else; atmospheric water vapor levels won't change. I don't know whether a large scale, ongoing intervention, such as permanently flooding a large area, could nudge this balance sufficiently to result in a sustained (if small) increase in atmospheric water vapor content, and thus an increase in warming. An interesting question! I wrote about the role of water vapor in global temperatures a while back at https://climateer.substack.com/i/60052576/you-thought-the-main-greenhouse-gas-was-co-but-its-actually-water-vapor https://climateer.substack.com/i/60052576/you-thought-the-ma.... My primary source was an IPCC report, specifically the sidebar on pages 8 and 9 of this PDF: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapt....

bonzini 3y ago

The water just moves, doesn't it? He's saying to build a canal.

coryfklein 3y ago
I guess it depends on whether such canals increase the net surface area. If you raise the ocean by 3mm across the globe, does it result in the same net increase in surface area as flooding a large swath of the Sahara?

snewman 3y ago

You are correct that water vapor is the primary greenhouse gas. Despite that, water vapor emissions are not generally considered to impact warming. I think that is because the water content of the atmosphere is already in balance due to the massive amount of evaporation and condensation (e.g. rain) that is constantly going on. If we dump some extra water vapor into the atmosphere, that will balance out as a bit of extra rain and/or a bit less evaporation somewhere else; atmospheric water vapor levels won't change. I don't know whether a large scale, ongoing intervention, such as permanently flooding a large area, could nudge this balance sufficiently to result in a sustained (if small) increase in atmospheric water vapor content, and thus an increase in warming. An interesting question! I wrote about the role of water vapor in global temperatures a while back at https://climateer.substack.com/i/60052576/you-thought-the-main-greenhouse-gas-was-co-but-its-actually-water-vapor https://climateer.substack.com/i/60052576/you-thought-the-ma.... My primary source was an IPCC report, specifically the sidebar on pages 8 and 9 of this PDF: https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapter08_FINAL.pdf https://www.ipcc.ch/site/assets/uploads/2018/02/WG1AR5_Chapt....