Here's a few highlights. Please see the actual notes before arguing, since there is inevitably much nuance missing here on Twitter.
-
-
Prikaži ovu nit
-
There is a plausible, though not undisputed, design to do DAC at $100-$200 / tonne of CO2 (https://www.cell.com/joule/fulltext/S2542-4351(18)30225-3 …, by
@DKeithClimate,@CarbonEngineer ). At $100 / tonne, making the US carbon neutral would cost about $600 billion per year, almost as much as the DOD.Prikaži ovu nit -
If, somehow, it could be done at $10 / tonne, the cost would be $60 billion per year. That's less than the cost of the Clean Air Act. Obviously, not small change, a major headache. But also a very doable cost, an interesting price point to think about.
Prikaži ovu nit -
It may not be possible to get the literal cost of DAC to $10 / tonne - there are some interesting thermodynamic analyses which suggest skepticism (eg https://www.pnas.org/content/pnas/108/51/20428.full.pdf … ).
Prikaži ovu nit -
But there are nonetheless three reasons to be optimistic: (1) research has already led to substantial cost reductions (arguably a factor 3 or so), and may well go further with more work;
Prikaži ovu nit -
(2) carbon intensity (CO2 / GDP) has been dropping by 18% per decade. If it continues, then as a fraction of GDP, the cost of capturing CO2 will go down commensurately; and
Prikaži ovu nit -
(3) large, wealthy countries like France and Sweden have CO2 emissions about 4 times lower, per capita, than the US. With similar approaches, the total cost of capturing CO2 in the US could be reduced several-fold.
Prikaži ovu nit -
Of course, points (2) and (3) are intertwined, not independent!
Prikaži ovu nit -
Does this mean a Clean Air Act priced solution (as a fraction of GDP) possible? Not yet. But it does seem like a real possibility.
Prikaži ovu nit -
There are also many potential problems - in particular, the cost estimates may simply be much too optimistic. More research needed on this and other points!
Prikaži ovu nit -
Finally, a point to emphasize: none of this means DAC is the right approach. Rather, I did this as a kind of bounding, worst-case analysis to see just how bad the problem is. In fact, there may well be much better approaches than DAC, and combinations of approaches.
Prikaži ovu nit -
I often chat with people who fatalistically see climate as an insoluble collective action problem. I'm reminded of people I met growing up who thought nuclear war (or acid rain) was inevitably going to kill us.
Prikaži ovu nit -
There can be a kind of hubris to pessimism, a failure to account for human ingenuity, & to think that if we can't see a full solution now, then one must be impossible. This doesn't mean one should just hope for the best; it does mean valuing small progress & imperfect solutions!
Prikaži ovu nit
Kraj razgovora
Novi razgovor -
Čini se da učitavanje traje već neko vrijeme.
Twitter je možda preopterećen ili ima kratkotrajnih poteškoća u radu. Pokušajte ponovno ili potražite dodatne informacije u odjeljku Status Twittera.