Elon Musk likes dual use technologies, so grow sugar and store it in a dry place. Capture carbon and solve obesity. Costs less per ton than the lowest cost DAC and can be scaled up. Also creates a backup of calories should we ever need it. And by the time we hit an ice age we warm the climate by releasing the carbon back into the atmosphere. Ideally we cultivate something like kelp to grow with high sugar content. Taking co2 from the ocean. So it does not compete with land use.

One sure way of killing all life on the planet, is to remove the CO2 from the atmosphere. When CO2 is reduced to 150 ppm, all plant life will start to die, closely followed by all animal life dependent upon it.

What goes around comes around. The water, O2. CO2, iron, carbon and all the rest of the elements that exist today will still be here 1,000's of years forward, perhaps in a different state. So our man Elon spurs a competition to efficiently and effectively sequester CO2 concentration back to its more benign state. Chemists know that it's not the element itself that is harmful but its concentration. so where can we put it? Looks like we have 2 main choices: either we inject it into the subterranean Earth or to outer space. We have released too much CO2 into the atmosphere precipitating harmful levels. Either we slow down and stop over consuming so much or get rid of it by sweeping it under the carpet. An overly part of humanity wants either to ignore the consequences or come up with an ineffective band-aid solution. The rest of the humans are just going along for the ride and feel somewhat helpless.

So the guy who wants to develop a way for interstellar travel to colonize mars and escape the foreboding and dark future ahead, while he instigates an effort to find better ways to deal with the problems terrestrially. It kinda fits doesn't it?

We have no choice but to learn to manage our environment or environments elsewhere. Mr. Musk understands this concept - forget global warming and begin global management. Climate change is natural, the ideal state debatable, but sustain and work from there before Ma Nature takes us out.

Or just buy 100 millions dollars worth of forest.

I guess sky diamonds would certainly qualify for the 100 year lock up (carbon dioxide to diamonds) - but I think it would struggle with the scale

Irrigate the Sahara, Arabian, and Gobi Deserts. Massive Desal plants to do it and pipe it in. Make sure drainage exists so it doesn't create Salton Sea kinda places. Would need Ammonia and fertilizer as well.

Instead of sequestering captured co2 we should split it. Releasing o2 and using carbon in manufacturing. ie. carbon fiber.

Why do we need to invent a machine to capture carbon when nature has already solved this problem. If we just re-forested the wild places we have lost over the last 50 years that would go a long way to setting things back on the right path.

This helps Musk rationalizing spewing ungodly amounts of pollution into the air to fulfill his wet dream of colonizing Mars.