One way to do it is to produce more bioavailable nitrogen to encourage more plant growth, then have animals and humans eat the plants. Now the carbon is stuck i

One way to do it is to produce more bioavailable nitrogen to encourage more plant growth, then have animals and humans eat the plants. Now the carbon is stuck in the animals. As long as those animal populations remain constant or grow you have a good carbon sink. You can even use the animals for food, as long as the animals never decompose it's fine. Or another one, as we move to renewable fuels, we might just have a cycle that traps a significant portion of the carbon dioxide in the fuel between use and creation, so the added carbon would be part of it's own separate cycle, and we could keep using it for energy storage ad infinitum. Why bury it? We can use it. As long as it's utility is high, we would only wind up with a slightly higher co2 concentration than baseline. If we bury it, then we have to take co2 from the natural carbon cycle that the biosphere needs to store energy, which means reduced biomass. But if we create a secondary carbon cycle for energy and food that only interacts with the natural one in the air we can store energy and food without impacting the biosphere as much.