[freebeard]

I didn't get through this whole thing, but it is in topic:

spectrum.ieee.org: STARTUPS BEGIN GEOENGINEERING THE SEA

Dozens of field trials and pilot projects have begun, and in 2025, Captura and several other companies will begin scaling up their facilities.

Their approaches are as diverse as they are bold. Some groups are growing kelp forests or microalgae in the sea. Others propose pumping seawater between shallow and deep layers to move carbon around. Two strategies caught IEEE Spectrum’s gaze—Captura’s ocean carbon dioxide removal approach, which sucks carbon out of the sea, and ocean alkalinity enhancement, which stores carbon in the sea. Both have inspired the engineering of novel, highly efficient electrochemical systems to treat copious amounts of seawater.
...
But the challenges facing marine carbon companies feel as grand as the companies’ plans. Most of their business models ultimately depend on selling carbon credits on voluntary markets. And to sell carbon credits, they must quantify how much CO2 they’re causing the oceans to draw down from the air. This can’t be done with physical measurements alone; instead, they must rely on numerical models that come with considerable uncertainty.

On top of that, a lot of environmental monitoring needs to be done to prove that marine carbon-removal strategies aren’t harming aquatic life. And then there’s the issue of scale. To make a dent in the more than 1,000 gigatonnes of excess CO₂ lingering in Earth’s atmosphere, and the few dozen gigatonnes continuing to be emitted each year from human activities, companies would have to process ocean water in biblical proportions.

So one company injects CO₂ into the oceans and another sucks it back out -- for money. ...to crash the market for industrial CO₂. [shrug]