Hi David, I would like people to consider a worst-case requirement to avoid catastrophic ocean acidfication, and work out what could be done to prevent such a catastrophe. Suppose (i) we are already close to the limit on the rate of acidification and (ii) the actual level of acidification has to be brought back to today's level within 20 years, if we are to have high confidence to avoid the catastrophe. I reckon we would need to peak the atmospheric CO2 level in ten years, and bring the level down below 350 ppm within twenty years from now. This is plainly impossible without CDR geoengineering to remove CO2 from the atmosphere. This will be expensive but the expenditure can be ramped up over twenty years as the geoengineering is ramped up. By 2022, the amount being of CO2 removed has to equal the amount of CO2 equivalent being put in the atmosphere. By 2032, the amount removed has to have been at least the enough to reduce the atmospheric CO2 level below 350 ppm. I think this is the magnitude of intervention that could be needed.
Meeting such a requirement could also serve to limit global warming to under 2 degrees, assuming that we have managed to keep the Arctic sea ice and avoided an escalation of methane emissions. It puts the whole business of CDR into a different perspective - a different ball-park. But this is certainly needed if we are to break out of old thinking and find solutions to provide a hospitable planet for future generations. Cheers, John -- On Fri, Mar 30, 2012 at 5:56 PM, David Keith <[email protected]>wrote: > Here are some thoughts on DAC. My comments tackle three questions: Is (1) > DAC geoengineering? (2) Could it be cheap enough to matter? And, (3) > Should we be concerned if the first markets for a low-carbon technology > involve getting oil out of the ground? I will leave the second question to > following email.**** > > ** ** > > First a few personal notes about self-interest and motivation: I serve as > president of Carbon Engineering (www.carbonengeering.com) one of the > firms developing this technology. I have tried to keep a wall between this > and my academic work on energy and environmental policy including solar > geoengineering by stopping academic work on DAC (e.g., no students, no > research grants to me as an academic) and by trying to keep out of policy > work on DAC except in venues where I am clearly wearing the industry hat > and not that of academia. **** > > ** ** > > It’s our job at Carbon Engineering (CE) to develop a technology that we > think may be social useful and also profitable to our shareholders. > Governments ought to regulate in the public interest. It’s wrong for > corporations (who are not people!) to preempt that regulatory role. **** > > ** ** > > Recent comments on this blog implied that folks such as me developing DAC > might be tools of the military-industrial-oil complex who have lost sight > of cutting carbon emissions. Here in Calgary I get attacked from exactly > the opposite position. When I challenge climate deniers and speak about the > need to cut emissions and thus oil production to zero (I oppose to Keystone > which about enough to get into a bar fight here) and I am now attacked on > the grounds that I am only saying this to promote a greentech company that > will only do well if we regulate carbon. (Attacked is no understatement, > one fellow took out a 10,000$ advert in the local paper that made this > specific allegation.) **** > > ** ** > > That said, I am having enormous fun with CE. The pace of technical > progress is fantastic and it’s the best group work environment I have ever > experienced. I feel lucky that we have a chance to do something useful. ** > ** > > ** ** > > Now down do it.**** > > ** ** > > 1. *Is DAC geo or mitigation?* Is it useful to think of DAC as > geoengineering or is it better placed as mitigation?**** > > Until net emissions are zero then any CDR method looks a lot like > mitigation in that a ton not emitted is the same as a ton emitted and > recaptured but for all the cost and enviro risk of CDR. This is > particularly true of DAC. I make that argument in a perspective in * > Science* attached here. **** > > ** ** > > Here is what I said in congressional testimony two years back > http://science.house.gov/sites/republicans.science.house.gov/files/documents/hearings/020410_Keith.pdf > **** > > ** ** > > SRM and CDR each provide a means to manage climate risks; they are, > however, wholly distinct with respect to**** > > **· **the science and technology required to develop, test and > deploy them; **** > > **· **their costs and environmental risks; and, **** > > **· **the challenges they pose for public policy and governance.** > ** > > ** ** > > Because these technologies have little in common, I suggest that we will > have a better chance to craft sensible policy if we treat them separately. > **** > > ** ** > > There is no magic line. Some CDR technologies, like ocean iron > fertilization have the big leverage (small input, big impact) of SRM and so > feel like SRM, but BECCS and DAC look more like mitigation. **** > > ** ** > > That said, the ability to pull out carbon in the long run does alter > climate strategy because it provides some chance to put the brakes on net > emissions harder if climate sensitivity turns out to be worse that we > expect. We make this point in: David W. Keith, Minh Ha-Duong and Joshuah K. > Stolaroff (2005). Climate strategy with CO2 capture from the air. *Climatic > Change*,*74*: 17-45. > (PDF)<http://www.keith.seas.harvard.edu/papers/51.Keith.2005.ClimateStratWithAirCapture.e.pdf> > **** > > ** ** > > For at least the next half century I see DAC as a kind of mitigation. I > think it’s only geoengineering if one is really talking about make net > anthropogenic emissions negative, and while I think that’s what we should > do it’s a long way off.**** > > ** ** > > Upshot: I would *strongly* prefer to move discussion of CDR to a separate > googlegroup. **** > > ** ** > > 2. *Cheap enough to matter? * > > We DAC can be brought to market at costs well under 200 $/tCO2 at scale > but without any fundamentally new technology. **** > > ** ** > > If we are right, then I think this matters because the costs of many > things we are today at large scale have emissions avoidance costs that are > about this large or larger (e.g., solar power, electric vehicles, wind > power at mediocre sites, etc..).**** > > ** ** > > More comments on costs in the following email.**** > > ** ** > > 3. *Should we be concerned if the first markets for a low carbon > technology involve getting oil out of the ground?***** > > ** ** > > Short answer: yes, I am concerned. I am nevertheless running a company > that will go after that market. Why?**** > > ** ** > > In the EOR applications we are looking at the lifecycle carbon emissions > of DAC-EOR transportation fuel would be about 40 gCO2e/MJ where > conventional oil is 95. There are two ways to look at this. **** > > * * > > *View 1*: All carbon emissions are bad as is anything that enables them. > (An overstatement of Ken’s argument.) I think it’s crucial to be clear that > goal is zero emissions. Nothing should get a “free ride”, and (my view) all > emissions should face a steep carbon price. That said, > ‘just-say-no-to-all-emissions can’t be an absolute guide to policy or one > would have to forbid building wind turbines and energy efficient windows if > their supply chains released carbon.**** > > ** ** > > *View 2*: A 50% cut in emissions per unit of delivered transportation > fuel is good. That plus getting started on DAC technology that can then be > applied elsewhere is doubly good.**** > > ** ** > > Getting a bit more real, the answer depends on the price of DAC. Two > extreme cases: **** > > 1. If APS is right, then DAC is so expensive that its irrelevant.**** > > 2. If Peter Eisenberger is right and DAC is ~30 $/tCO2 then we will > have a huge amount of extra oil but then it will also be much cheaper than > we thought to cut emissions.**** > > > I think the real world is likely to in the middle: Suppose we can bring > DAC to market at a long run cost in the 100-200 $/tCO2 range, then DAC-EOR > will make money and produce oil, but *only* under a carbon regulation > like California’s LCFS that and that same regulation will also drive > emissions down. Like other low carbon technologies DAC-EOR depends on > government mechanisms to restrain emissions (carbon price or equivalent) * > *** > > ** ** > > Under these assumptions, since DAC-EOR only works with a significant LCFS > carbon price (e.g., 50-150 $/tCO2) then the cost of transportation fuels > will go up eliminating direct rebound.**** > > ** ** > > There is a danger of perverse incentives making some DAC > counter-productive when linked to EOR, but with reasonably sensible carbon > policy (e.g., a tax or some even price) I think the net effect is still too > strongly restrain emissions. [Self-interests warnings apply, your mileage > may vary] **** > > ** ** > > There is a tension between the cost of pollution control and the readiness > of governments to impose controls. If DAC with EOR really did drive the > cost of DAC down to near 100$/tCO2 about 1 $/gallon gas for the equivalent > of carbon-neutrality, then DAC could help by making it easier for > governments to impose stronger carbon constraints. Look what happened to > car emissions controls since the early 1960’s. **** > > ** ** > > Last point: no technical fix from solar-PV and wind to DAC will solve the > climate problem without broad commitment that the problem is worth solving. > **** > > ** ** > > ** ** > > ** ** > > -- > You received this message because you are subscribed to the Google Groups > "geoengineering" group. > To post to this group, send email to [email protected]. > To unsubscribe from this group, send email to > [email protected]. > For more options, visit this group at > http://groups.google.com/group/geoengineering?hl=en. > -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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