I think the point is that even if we can scale up DAC to work, we need some carbon-free source of energy to power it. Fixing the atmosphere essentially means we

I think the point is that even if we can scale up DAC to work, we need some carbon-free source of energy to power it. Fixing the atmosphere essentially means we need enough non-emitting energy to run civilization since 1850 in reverse, and preferably much faster than 1x.