I totally agree with these timescales. Somewhere between 2060 and 2100 is the timescale for very low carbon emissions worldwide. Anything earlier is simply unrealistic.
This is the central argument for geoengineering- both SRM and carbon capture from atmos. john gorman ----- Original Message ----- From: Andrew Lockley To: Ken Caldeira Cc: geo-engineering grp Sent: Tuesday, July 26, 2011 1:24 PM Subject: [geo] Re: More detail per list member request Ken I understand your position, and I wasn't attempting to suggest you and your co-authors were guilty of 'bad science'. However, the problem with your approach is that, in the absence of broader papers, it is not clear how policy makers could react to the risks I've outlined. The risk is that 'limited' papers, such as yours, could potentially give false hope to policy makers, when 'abject screaming panic' is actually a more appropriate response. My suggestion is that we can approach this problem mathematically. Instead of modelling each factory, you look at the first, second and possibly third differentials on per-capita emissons, and then combine them with population figures to derive maximum transition rates for emissions. The first differential is the rate of technology implementation - equivalent to the potential rate of decommissioning. The second differential is the rate of political/technological change - how quickly the social system is moving to prefer one carbon intensity path or another, equivalent to the potential rate of 'steer' onto a new, low carbon path. The third differential would (I think) be related to the volatility of the political/technological process - how suddenly or otherwise new solutions propagate. This is all perhaps a little abstract, but it's a lot easier than counting planning applications for car factories. This will then give you a somewhat-tolerable estimate of the political and technical intertias in the system. By reversing the observed accelerations, you can work out what a realistic level of decommissioning or diversion of development may be possible. You can also approach the problem sociologically, but examining uptake rates for previous energy technologies. These will be a function of the price differential, but the transition from industrial steam to industrial electricity is a reasonable example, and from my relatively limited knowledge of industrial history I reckon it was about 80yrs for the transition to fully complete, based on the timescale of first application (about 1890 to 1960). If we take the first low-carbon technologies to be wind turbines in about 1985, we can derive from that an end date of around 2060 for the global carbon economy - provided the renewable capacity is capable of delivering the energy needs of the globe. If we are to consider another milestone and assume that we're about 10yrs away from commercially available organic thin-film photovoltaics, we're probably looking at a date of 2100 for a decarbonised world. This is a very different approach, but one which I believe has some historical credibility. I'd suggest an S-curve during this time, to model a technology transition which peaks at around 40 years into the process. If you look at communications technologies, we're probably on a shorter timescale, but it's conceivable that we're about half way through the replacement of fixed phones with mobile phones at present. I appreciate that this is possibly a little 'off topic', but I believe it is worth considering as it addresses a key issue in geoengineering policy, and that is whether it's currently Plan A or B. My suggestion is that geoengineering is now likely to be essential. It is no longer a possible reaction to potential political failure, but rather an inevitable need in the face of insurmountable rates of political social and technological change. A On 26 July 2011 11:09, Ken Caldeira <[email protected]> wrote: Not considering everything under the sun is not a problem with our paper, it is what makes a scientifically defensible quantification possible. We note in the paper that in quantifying future co2 emissions from existing co2-emitting devices, we are quantifying only a piece of infrastructural commitment. We started that paper thinking we would show that existing co2-emittig devices were enough to send us over 450 ppm and 2 c. We never intended to present s realistic scenario. I believe that existing infrastructure that does not directly emit co2 (eg automobile factories), not to mention political inertia, are enough to push us beyond these levels (in the absence of dramatic political change and engineering effort). Sometimes, when writing scientific papers, it is better to answer a limited question well rather than answer a broader question poorly. Scientific papers are like statements in a discussion. We generally try to say the first word on a topic, not the last word. Insofar as different sources of commitment can be quantified in a technically defensible way, I encourage others to do so. If we think of a good way to do so; hopefully we will beat you to it. When i have access to my laptop, I will send a copy of the paper. Ken Caldeira [email protected] +1 650 704 7212 http://dge.stanford.edu/labs/caldeiralab Sent from a limited-typing keyboard On Jul 26, 2011, at 11:25, Andrew Lockley <[email protected]> wrote: thanks for that. I forwarded it. The Caldeira paper has the problems anticipated, ie that the political/construction/sociological trajectory isn't included. There's no way China can stop it's emissions growth dead. It's simply not going to happen. I couldn't see the other graph, it didn't come out very well. I assume it's dt vs CO2e ppm. I maintain that the evidence supports SRM as plan A A On 26 July 2011 04:54, <[email protected]> wrote: Andrew - This is to ask you to forward the following to the geo list. I am sure it won't be successful from my computer These further provide detail on the diagrams that a geo list member has asked for (and in the "Word" attachment) List and Andrew As a subscriber to (behind a pay-wall) Science magazine, I was asked if I could provide the graphs I was working with from the Davis-Caldeira paper I commented on a few hours ago. I think this should not violate any copyright prohibitions - and might even sell more for the journal Science (my favorite). The necessary three data point-pairs are the right most in parts C and D (I couldn't find a way to remove A and B.). These 3 point-pairs for the year 2060 can then be put in the (free) material I referenced by Dr David Wasdell. - found at http://www.apollo-gaia.org/Climate_Sensitivity.htm . The second graph is taken from the attachment article by Dr. Wasdell that you provided on 20 July. This is the best copy I could find/copy. If one rotates it CCW, one will find that the horizontal axis runs from 140 ppm to 560 ppm with 280 ppm in the middle, plotted on a log base 2 scale. The three point - pairs will be found to lie to the left of the 440 ppm dotted line and below the "Charney" diagonal - a region that Dr. Wasdell says mis-reads the historical evidence. I hope this is helpful. Ron -- 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. 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.
