Technology

Thought experiment: burn a fuel, now how much energy do you think you have to use to go capture all the CO2 molecules from the air and turn them into a material? At best, you're going to need twice as much energy to recapture the fuel as what you got from burning it.

But you say: "the energy to power CO2 capture will come from green sources". Yes, but these require energy to be produced and you're encumbering already lower density energy sources than fuel with reversing CO2 debt, when we need those energy sources to power everything else.

It's a good way to kick the can down the road and say "we'll fix it later, when we have lots of cheap energy that we can afford to waste."

The answer is, broadly in this order:

• Don't cut old forests, these are the best at absorbing CO2 and keeping it in the ground.
• Minimize forest fires with strategic multi-species tiling, spacing, having grazers eat biofuel
• Reduce energy consumption through mass transit, home, agricultural and industrial innovation to improve efficiency and reduce waste
• If you are already not cutting forests, plant trees (takes them centuries to become efficient), grasses and seaweed where adequate (e.g. Scottish highlands) and try to sequester them in swamps, mines or furniture.
• Move to 100% green energy sources
• Use emission-neutral vehicles
• Invent batteries that can store surplus energy for baseload power and shut down nuclear powerplants (if you must..).
• If there is any surplus green energy left, capture as much concentrated CO2 with algae at CO2-intensive exhausts like natural gas plants and test with artificial methods to see how they compare with plant-based capture.
• Artificial direct-from air capture with whatever unused energy we have left after all these steps <-------this is this article is right here at the end, once all the other mammoth problems have been solved