Dear Jim--With respect to the set of available global tests, it seems to me your perspective is a bit narrow. Aside from the fact that the GHG emissions are a test (though of a different sort in some ways), we have quite a good test with halocarbon emissions and then their control (this is mainly a chemistry test, but is a global test). Discovery of the ozone hole showed that understanding was limited (failure to treat heterogeneous chemistry), so that process was researched and included, and our understanding keeps improving so that we seem now to be doing fairly well (still some ways to go on carbon tetrachloride, as I understand it).
And on this issue of a test needing to be fully global, it seems to me there is some confusion. IPCC counts some regional forcings as global (think sulfates)--and indeed there must be some adjustment between hemispheres as the Earth¹s energy balance adjusts. There has also been an interesting Œexperiment¹ as emissions in the North Atlantic basin have gone up and then down, and now emissions are rising in the southeastern and southern Asia region (China, India, etc.). I am not sure we have yet had much learning from that, but a lot of potential. And we can also get at the question of whether and by how much regional forcings affect the global environment, so we can determine if regional and/or seasonally varying interventions make any sense to consider. As for the SO2 emission changes being a test, the same argument might be made with respect to biomass emissions, changes in albedo due to land cover change, and more‹it seems to me we have quite a few types of changes to look at, admittedly many not done originally as a test of geoengineering. I also think that what is not being adequately considered in this discussion and in the formulation of your arguments and position is that the geoengineering activities being proposed now are to try to keep the climate near to what it is, versus the proposals a half century ago that were to change the environment to a new state that some elite thought would be better (that is where the true hubris issue deservedly arose). Right now, it is our ongoing GHG emissions that are changing the world to a state that will be different (likely in surprising ways, where thresholds and nonlinearities are much more likely, etc.) than for interventions trying to keep the climate state as it is, etc. Not one of us is arguing that we would pursue these interventions absent the threat (or actual dramatic changes) resulting from global warming. It just seems to me that the climate going more and more away from the baseline climate we have been accustomed to is likely to involve a lot more adverse and surprising consequences than undertaking some of the interventions in ways that keep the climate near where it is. Not that there can¹t be problems, but hopefully research can help us to minimize these. In my view, we should be much more worried about our ongoing changes in the climate due to GHGs and the limits to adaptation that exist, than about the sorts of geoengineering interventions being considered‹research can help indicate if this is a reasonable presumption or is seriously flawed, but I just don¹t understand the position of starting out in the reverse ordering. Best, Mike On 9/29/10 8:42 PM, "Jim Fleming" <[email protected]> wrote: > Colleagues, > > Is global climate engineering untested? -- Yes, with the exception of the > historical example I provided, which was US and Soviet nuclear devices > detonated in the magnetosphere between 1958 and 1962 as a form of > sabre-rattling during the Cold War. These tests led to the Limited Test Ban > Treaty. > > Is global climate engineering untestable? -- Yes, since a global ³test² would > be an implementation. The key word is global. OIF patch experiments are not > global, nor are they justification for SRM tests that ³pump it up and spew it > out.² > > Do I support research in climate engineering? Yes, but keep it indoors and > please, please include the humanists and social scientists and take their work > seriously. Remember, climate engineering is not to be left to the > technocrats. We need research by ethicists, sociologists, psychologists, > historians, etc., > > Do I support Ken's 3-phase program that escalates from computer modeling and > lab tests to ³development of a deployable system?² No, this outlines a > slippery slope greased with conditional statements. Caldeira and Keith use 31 > ³coulds² and 9 ³mights² in the short Issues in S&T article. Yet, we do not > disagree on Phase I, except I would argue for more funds going to atmospheric > science in general, not earmaked for geoengineers. > > Now, I have to leave for a meeting about military efforts to control the Van > Allen Belts during the Cold War. > > Jim > > On 9/29/10 7:01 PM, "Ken Caldeira" <[email protected]> wrote: > >> Robock et al (Science, 2010): "We argue that geoengineering cannot be tested >> without full-scale implementation." >> Fleming (Slate, 2010): "Global climate engineering is untested and >> untestable..." >> >> In summarizing this conversation, it seems universally agreed that flat >> statements like these are simply untenable, in that everyone acknowledges >> that there are many tests that can be done (both in the real world and in >> numerical simulations) that will help improve our ability to predict >> consequences of deployments of climate intervention systems. >> >> (Couldn't someone equally argue that "climate consequences of emissions >> reductions are untestable" ?) >> >> As with all large scale deployments in complex systems (c.f., electricity >> generation and transmission, highway systems) there is no way prior to >> full-scale system deployment to be able to predict all consequences of that >> deployment. Nevertheless, there are a large number of things that can be done >> to improve our predictive ability. >> >> It is clear that we need either good models or lots of time with >> mid-sized-tests to predict climate consequences of a full-scale deployment >> with confidence.. >> >> This state of affairs makes it clear that we should be working hard to >> improve and test climate models and to conduct field experiments that can >> improve process representations in those models. As Stephen Salter points >> out, there are many things to be tested beside large-scale climate >> consequences. >> >> Alan Robock and co-authors may feel they knows what they meant when they >> wrote those words, but I think what they meant was not what they wrote. It >> seems to me that the content of their statement is something like: >> >> "If we are unwilling to rely on climate models and are unwilling to spend >> decades doing mid-sized tests in the environment, then there is no way to >> test the climate consequences of geoengineering schemes without full-scale >> implementation." >> >> To understand large scale climate consequences of a geoengineering >> deployment, we will most likely need to rely on climate models, and I think >> that is what Robock et al meant to say. >> >> There are plenty of tests we can do in the field (e.g., testing hardware, >> tests aimed at improving physical process understanding and improving >> representations of those processes in the models). We can test climate model >> performance using a wide variety of observations (e.g., Mt Pinatubo). We can >> also test various climate intervention proposals in climate models (and our >> trust in those results of those tests should increase as models improve and >> are evaluated on a broader range of measures). >> >> It is damaging to efforts to conduct these climate engineering tests to have >> people going around saying things like "geongineering cannot be tested >> without full-scale implementation" when this statement is clearly wrong as >> written: there are many valuable tests that can be done, both in the real >> world and in models. >> >> ___________________________________________________ >> Ken Caldeira >> >> Carnegie Institution Dept of Global Ecology >> 260 Panama Street, Stanford, CA 94305 USA >> +1 650 704 7212 [email protected] >> http://dge.stanford.edu/labs/caldeiralab @kencaldeira >> >> "Marriage cannot be tested without full-scale implementation." >> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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