In the bland words of the Intergovernmental Panel on Climate Change, “only in the case of essentially complete elimination of emissions can the atmospheric concentration of CO2 ultimately be stabilised at a constant [far higher!] level.” This heroic feat would require new technologies and the replacement of today’s installed infrastructure for power generation, transportation, and manufacturing. This seems impossible. In the real world, Asia is industrializing, most new power plants burn coal, and emissions are accelerating, increasing the rate of increase of the problem.
Drexler dismisses the “magic nanotechnology” trope and suggests what technological developments could do for us:
According to fiction and pop culture, it seems that all tiny machines are robots made of diamond, and they’re dangerous magic — smart and able to do almost anything for us, but apt to swarm and multiply and maybe eat everything, probably including your socks.
A solar array area, that if aggregated, would fit in a corner of Texas, could generate 3 terawatts. In the course of 10 years, 3 terawatts would provide enough energy remove all the excess carbon the human race has added to the atmosphere since the Industrial Revolution began. So far as carbon emissions are concerned, this would fix the problem.
Drexler has further discussion of his essay on his blog, Metamodern.