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In the ideal form of net-zero, the direct air capture of CO2 is only needed to offset the hard to abate emissions—ie. jet fuel, global shipping, embodied carbon

In the ideal form of net-zero, the direct air capture of CO2 is only needed to offset the hard to abate emissions—ie. jet fuel, global shipping, embodied carbon (like concrete). That future is dependent on wide scale decarbonization (in progress, albeit slowly) and, as you mention, an externally imposed requirement—from either governments or consumers. However, that period of net-zero should be a waypoint on the path to sequestering historical carbon (the real goal) but the only way to get there is to first decarbonize everything that we can. In a way, carbon credits/offsets might actually be a deterrent to that future. There is a notion of a “circular carbon economy” where CO2 is made into useful products in addition to sequestering for carbon credits, but you are right that the dominate use case for captured CO2 is enhanced oil recovery (EOR). Put to that end, there are very few practical long term benefits to sequestering carbon. That said, one benefit of offsets, tax credits, etc. is funding the creation of the carbon dioxide removal technology we will need by 2050 to offset the hard to abate emissions, but that tech is only useful if we first decarbonize as it hard to imagine it can be scaled up to the 40 gigaton level based on the data today.

vkou 4y ago
So, we only need to do incredibly inefficient atmospheric capture of a one per two thousand part gas at a planet-wide scale with technology that nobody uses in production, with economic incentives that will somehow arise, in a world where gas prices going up 15% causes governments to fall. We are well on track to get there.
- adregan 4y ago
  It is a very steep climb and nearly impossible given the status quo, and it's easy to get discouraged, so I understand your sarcasm. I've spent the past few months studying up on the state of the carbon removal world, and I was encouraged by a couple technologies (there is a lot of cool stuff out there, but there are some which seem more practical than others), which are in the "carbon utilization" bucket—appealing because the CO2 is turned into something with value rather than an abstract credit. 1) using captured carbon to create concrete aggregates as well as in the curing of concrete can make for a stronger material, a carbon sink, and doesn't require much change in behavior 2) turning captured CO2 into carbon fiber more cheaply than the current process could have knock on climate benefits if carbon fiber becomes cheap enough that it enjoys widespread use. I hope the circular carbon economy pans out because it has the power to stimulate minds. Making something of value out of the air is very "sci fi" and doesn't really ask as much from the populous at large in terms of understanding a pretty complex issue like carbon sequestering.

vkou 4y ago

So, we only need to do incredibly inefficient atmospheric capture of a one per two thousand part gas at a planet-wide scale with technology that nobody uses in production, with economic incentives that will somehow arise, in a world where gas prices going up 15% causes governments to fall. We are well on track to get there.

adregan 4y ago
It is a very steep climb and nearly impossible given the status quo, and it's easy to get discouraged, so I understand your sarcasm. I've spent the past few months studying up on the state of the carbon removal world, and I was encouraged by a couple technologies (there is a lot of cool stuff out there, but there are some which seem more practical than others), which are in the "carbon utilization" bucket—appealing because the CO2 is turned into something with value rather than an abstract credit. 1) using captured carbon to create concrete aggregates as well as in the curing of concrete can make for a stronger material, a carbon sink, and doesn't require much change in behavior 2) turning captured CO2 into carbon fiber more cheaply than the current process could have knock on climate benefits if carbon fiber becomes cheap enough that it enjoys widespread use. I hope the circular carbon economy pans out because it has the power to stimulate minds. Making something of value out of the air is very "sci fi" and doesn't really ask as much from the populous at large in terms of understanding a pretty complex issue like carbon sequestering.