I feel that terra preta is the way to go. You use plants to concentrate carbon. You make biochar. And then you put it back in the soil, so you're not depleting

I feel that terra preta is the way to go. You use plants to concentrate carbon. You make biochar. And then you put it back in the soil, so you're not depleting it of nitrogen, phosphates, and minerals. The waste heat that you get from making the biochar is useful energy -- solar energy, really -- that you can use to heat homes, make hot water, and run heat engines. Maybe even the Haber process too? The chief challenge I see is how to reduce human labor requirements without increasing capital requirements too much. I'm also a little concerned about eventually diluting the soil with too much biochar. Because you're sucking carbon out of the atmosphere, but the amount of phosphates and such is remaining constant.