The carbon cycle evolved to be near enough to circular to not have run itself out of carbon in millions of years. It maintains this balance though changes in evolution that take tens of thousands of years minimum, not fifty. We’ve all but doubled the amount of carbon in the atmosphere, we need to get as much of it out as soon as possible or we know what will happen.

We’ve already done vast damage, and are well on our way to all but exterminating our reefs and a large slice of ocean life. That’s not can happen, that’s absolutely will happen unless we intervene. Much like with dams, the chance of some localized ecological damage is not just acceptable but a bargin compared to what doing without really means.

Except it’s not. After a fire a lot of it goes into the air, the little mass remaining goes into ash to be dug up by new growth that would have otherwise used atmospheric carbon. While some may eventually be buried so deep that it escapes the carbon cycle it took on the order of millions of years to bury what we’ve dug up in fifty. Nature can’t solve this on its own, not on the time scales necessary to avoid catastrophe. Nothing proposed here seems to require pumping an equivalent carbon from underground into the atmosphere, so there seems to be little risk of anything but a net benefit.

Not at anything like the needed scale

If you look at who is involved, its a bunch of forestry and fire ecology types with a few tech people supporting them