Water pumped into a desert would evaporate and increase formation of clouds which would in turn increase the albedo of the Earth. Would this help to cool the planet more efficiently than trying to capture carbon?

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    $\begingroup$ Deserts are often quite light in color, meaning they actually have decent albedo... whereas water is less than 10%. So it'd increase absorbed energy as a whole outside of the clouds. Think how much water you'll have to pump to get a significant increase in scale of cloudcover enough to effect global temperature? This answer to a question about pumping water into the Sahara gives a reasonable breakdown on cost. $\endgroup$ Aug 15 at 0:26
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    $\begingroup$ The best way to increase albedo on the Earth is to increase snow/glacier/ice cover. That being said, carbon capture is an extremely inefficient way to to cool the planet. So perhaps its not a bad comparison. $\endgroup$
    – f.thorpe
    Aug 15 at 5:04
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    $\begingroup$ You'd have to take into account that water vapor is a greenhouse gas... $\endgroup$ Aug 15 at 7:09
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    $\begingroup$ In a related geoengineering issue, one of the researchers at my institution recently co-authored a paper on "what if we had tried to move water around to end the 1980s East African drought?" Their model shows that millions of pipes would have been needed and the process would have caused a drought elsewhere: scripps.ucsd.edu/news/… In other words, this would be a giant project with its own side effects quite aside from evaporating a bunch of water in a desert. $\endgroup$ Aug 15 at 16:20
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    $\begingroup$ Given there is no constant band of cloud in the equatorial regions of the Pacific, Indian and Atlantic oceans I wouldn't have thought so. $\endgroup$
    – Fred
    Aug 16 at 4:24

Sorta. But now you're hypersalinating a soil profile and once it evaporates it's now a salt flat. Better strategy is build "Pools" at high elevation then have gravity send the water back to the ocean in one big loop. Water will evaporate from surface, increasing ambient humidity overtime. On average, swimming pools lose about a quarter of an inch of water each day to evaporation (155 gallons per 1000 square feet) So a one square mile sized retainment area will evaporate 4.3 million gallons a day. Another idea is seawater solar still. Pumped water would enter a green house semi-buried The humidity would rise and be diverted to a pump which said water would percolate into the ground. This ground water would sustain new vegetation which in time would humidify the surrounding area. enter image description here


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