That's not a techno solution worth to dream about, the real techno solution is a fine grained control of weather (like https://viento.ai) and in that case the extra CO2 in atmosphere will be naturally sequestered in fields and farms in Sahara.
But the team is interesting indeed. Incidentally, there's an online SSC meetup with Jaan Tallinn as guest, _today_: https://www.lesswrong.com/events/jQQYCdtiH5d3CtrNC/jaan-tall...
What he is qualified for is running this sort of effort. I just don't know what to call this sort of effort.
Viento is a ‘moonshot’ nonprofit pioneering targeted weather security... by combining big data, forecasting breakthroughs and AI directed weather interventions... framed as "break glass in case of climate emergency."
So... I don't like the idea. I do however, like the way he puts together moonshot projects, generally. Maybe this will evolve into something better. It's useful to have 0.X% of people working on tech, to be doing it in an environment that isn't standard academia or big tech.