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Comment by DougN7 | Hacker News Reader

I’m not even quite an arm chair scientist, but this seems like a big deal to me. It seems like it would affect a lot of assumptions that have been made over time involving evaporation like weather and climate predictions. Can anyone that knows more about this chime in?

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This is a bit of inside baseball but many climate models use something called a "bulk formula" for evaporation [], which is empirically derived from real observations of the sea surface. Hopefully which (already) captures this novel phenomenon.

[] https://oceanwiki.ethz.ch/doku.php?id=lecture7:bulkformula

>real observations of the sea surface

I suspect this effect is more relevant to plant transpiration, which has a massive effect on terrestrial rainfall patterns.[0]

Do they use similar methodologies to capture land-based evapotranspiration? Does the resulting simplified model have inputs that allow it to capture real-world variations in this effect?

[0] https://www.nature.com/articles/nature11983

Yes, this is a big deal. You can think an analogy to the photoelectric effect where a photon excites an electron and for the photomolecular effect, a photon with the proper 'excites' a molecule, breaking the molecule free from its bulk.

Nothing in the abstract seems to tell the magnitude of the effect or how it differs in hydrogels vs other natural surfaces. Anyone have details on those from behind the paywall?

After checking a widely-used hub of scientific articles, in this case unsuccessfully, a possible next step is to send an email to one of the authors of the article to see if they have a draft or preprint version of the article that they can email back to you. Often the differences between the preprint version and the published version are insignificant.

I found https://arxiv.org/pdf/2201.10385.pdf by the same authors.

If I read it correctly, it says the theoretical limit for thermal evaporation is 1.45 kg/(m²h), while experimentally, values as high as 4-5 kg/(m²h) and over 10 kg/(m²h) have been reported in two-, respectively three-dimensional structures.

That’s a huge difference, but in my uneducated opinion not likely to be completely caused by this effect.

Edit: reading https://news.mit.edu/2023/surprising-finding-light-makes-wat..., which says “and the excess has been significant — a doubling, or even a tripling or more, of the theoretical maximum rate”, I read that correctly. I’m beginning to doubt my “not likely to be completely caused by this effect” hunch, though,

First pdf source says it happens in darkness with hydrogels too, but doesn't directly say the magnitude (has another reference), just that it is smaller.

Don’t worry, it’ll be no time at all until the climate xrisk people explain why this means even more draconian measures are necessary.

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