Climate scientist on man-made clouds

Marin B

Active Member
Freakonomics (podcast) recently had an episode of "Tell me something I don't know" where invited guests are interviewed about a topic of their expertise and the audience picks the winner. The winner of this episode was a climate scientist, Kate Marvel, (bio here) who discussed the role of clouds in climate change. At one point the host made reference to "mad scientists" who want to make clouds and put a sunscreen around the planet:

DUBNER: Well let me ask you this, since low hanging clouds, at least some can generate cooling, right, by blocking the sun, is it not possible to generate on purpose a certain kind of low hanging cloud? I’m guessing you know a lot more about this than I do, but I know some mad scientists who want to do some sort of cloud seeding with salt water vapor or with dust to kind of create a nice little sunscreen around the planet. You like that idea?

MARVEL: No, I hate that idea. But it’s not a stupid idea. It would work. It would —

DUBNER: You’re such a lovely bundle of contradictions.

MARVEL: So, it would probably cool down the planet. Right. If you block sunlight it cools down. But I don’t like that idea because I like sunlight, and plants like sunlight. If you look at the tracks of ships crossing the Atlantic, you can actually see that they are cloudier, because those ships are spewing out gas and dust, those particles are nucleating clouds, and it’s actually cooler where a ship’s been than it is where a ship hasn’t been.

Content from External Source
The entire episode is interesting, but if you're interested in the cloud part it begins at 13:40 on the podcast - player towards the top of the episode page, here:, transcript is below it.

Not sure if this fits in the general debunking forum - but I thought it could be useful to counter claims that people like David Keith are already involved in making clouds to combat climate change - here's a climate scientist who says this is an "idea".