Seeding clouds over the ocean

Seeding clouds over the ocean

From PhysicsWorld.com: Cloud-seeding ships could combat climate change:

It should be possible to counteract the global warming associated with a doubling of carbon dioxide levels by enhancing the reflectivity of low-lying clouds above the oceans. […] The idea relies on the “Twomey effect”, which says that increasing the concentration of water droplets within a cloud raises the overall surface area of the droplets and thereby enhances the cloud’s albedo. By spraying fine droplets of sea water into the air, the small particles of salt within each droplet act as new centers of condensation when they reach the clouds above, leading to a greater concentration of water droplets within each cloud.

The plan, from American and British researchers at the National Center for Atmospheric Research in Boulder, US, is to use a “worldwide fleet of autonomous ships spraying salt water into the air”.

We know for a long time that clouds can heat the planet by trapping the radiation given off from the Earth’s surface, and at the same time cool the planet by increasing the albedo and reflecting radiation back into space.

So the general idea is not new: increase the albedo through low-lying clouds over the ocean. But the ships are.

Unmanned, wind-powered ships would seed the clouds with unconventional sails. Fitted with a number of 20 m-high, 2.5 m-diameter cylinders known as “Flettner rotors” that would be made to spin continuously. This spinning would generate a force perpendicular to the wind direction, propelling the ship forward if it is oriented at right angles to the wind.

There was no comment on unintended consequences, however… More salt in the air, clouds perhaps moving over land zones causing acidification?

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