> extremely prohibitive and far beyond current capacity, but assume for the sake of argument that this is a problem that could be solved.
Even if we did have this magical way to add another Earth's worth of energy production, it would first need to be put to use replacing about 25,000 TWh of carbon-emitting energy (used in electricity production, transportation, heating, metal refining, concrete production, etc). We need to close the sucking chest wound of carbon emissions before we worry about anything else.
Yes, and it looks like the quickest, cheapest way to do that is by electrifying everything we can and generating electricity with wind, solar, and battery storage. In the US, the most economical way to get a reliable grid out of that is 2X energy overproduction and four days of battery (citation in another comment I posted here.)
With 2X overproduction, we've got lots of spare energy, so by the time we're getting most of our energy this way, we'll also have lots of energy for DAC, which can soak up the excess power whenever it's available.
I feel like that's the obvious solution at this point, but there's still so much waffling going on. And half the political parties on Earth still aren't even interested. If we could just get to work building like our lives depended on it (because they do), I would actually have some hope for the future.
I do want to stress that we shouldn't be thinking about DAC until we've carpeted the world's deserts with solar, and it's going to be a long fight to make that a possibility. The economy still hasn't kicked its oil addiction, and it's starting to look really pale and disheveled...
The politics is awful but the one thing we have going for us is the stunning and continuing price drop for wind, solar, and batteries. Now that's it's getting cheaper than other sources, the transition is unstoppable.
Meanwhile, all the non-disastrous IPCC scenarios include large scale carbon absorption after 2050. We can't start on a dime. The price drop for solar happened because the more of something you make, cumulatively, the cheaper it gets. We need that process to start for DAC, so it's cheap when we need it.
And we already have places with lots of renewables, that pay people to consume power when there's extra. With more renewables, that will be a bigger issue. DAC can already start being the flexible demand we need.
There are several dangers with "early DAC". One is that fossil fuel proponents will use it as a specious way of saying climate change is "solved" so we can burn as much carbon as we want. Sort of a Jevons paradox[0] where the efficiency is mostly fictitious.
Also, scaling up a DAC industry while all industry is still necessarily carbon-intensive is a bad idea. And we also need to be on a decarbonizing "war economy", and DAC might distract from that. DAC (or some other kind of re-terraforming) needs to phase in after decarbonization. Timing is going to be critical because we left things so late.
The fossil industry is going to make specious arguments no matter what we try to do. It's not like they'll say "oh, you're focusing on solar, guess we'll just shut down our businesses then."
In my ideal world, we'd have a fee on CO2 emissions equal to the cost of verifiably absorbing them, and use the money to actually absorb them. If the fossil industry wants to rely on DAC and keep emitting, that's what that looks like. Pointing that out is an easy response to those specious arguments; the fossil industry definitely does not want that world, because the fee would be high enough to drive rapid adoption of low-carbon technologies for everything but the most difficult cases.
Back in the real world, since DAC is at the start of its exponential adoption curve and depends on political action to reach any kind of scale, it's unlikely to get big enough to interfere with renewables in any meaningful way over the next decade at least, probably more. We can afford to work on it.
Even if we did have this magical way to add another Earth's worth of energy production, it would first need to be put to use replacing about 25,000 TWh of carbon-emitting energy (used in electricity production, transportation, heating, metal refining, concrete production, etc). We need to close the sucking chest wound of carbon emissions before we worry about anything else.