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?
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.