And although not directly geoengineering (as such), an article came out recently that may be of interest for those looking into any kind of impacts of geoengineering related to temperature, precip, agriculture, and so on, using CMIP5 models (or even CMIP3 models): Implications of regional improvement in global climate models for agricultural impact research Julian Ramirez-Villegas1,2,3, Andrew J Challinor2,3, Philip K Thornton1,4 and Andy Jarvis1,2
http://iopscience.iop.org/1748-9326/8/2/024018/ Global climate models (GCMs) have become increasingly important for climate change science and provide the basis for most impact studies. Since impact models are highly sensitive to input climate data, GCM skill is crucial for getting better short-, medium- and long-term outlooks for agricultural production and food security. The Coupled Model Intercomparison Project (CMIP) phase 5 ensemble is likely to underpin the majority of climate impact assessments over the next few years. We assess 24 CMIP3 and 26 CMIP5 simulations of present climate against climate observations for five tropical regions, as well as regional improvements in model skill and, through literature review, the sensitivities of impact estimates to model error. Climatological means of seasonal mean temperatures depict mean errors between 1 and 18 ° C (2–130% with respect to mean), whereas seasonal precipitation and wet-day frequency depict larger errors, often offsetting observed means and variability beyond 100%. Simulated interannual climate variability in GCMs warrants particular attention, given that no single GCM matches observations in more than 30% of the areas for monthly precipitation and wet-day frequency, 50% for diurnal range and 70% for mean temperatures. We report improvements in mean climate skill of 5–15% for climatological mean temperatures, 3–5% for diurnal range and 1–2% in precipitation. At these improvement rates, we estimate that at least 5–30 years of CMIP work is required to improve regional temperature simulations and at least 30–50 years for precipitation simulations, for these to be directly input into impact models. We conclude with some recommendations for the use of CMIP5 in agricultural impact studies. ________________________________________________ Simon Driscoll Atmospheric, Oceanic and Planetary Physics Department of Physics University of Oxford Office: +44 (0) 1865 272930 Mobile: +44 (0) 7935314940 http://www2.physics.ox.ac.uk/contacts/people/driscoll ________________________________ From: geoengineering@googlegroups.com [geoengineering@googlegroups.com] on behalf of Simon Driscoll [drisc...@atm.ox.ac.uk] Sent: 01 August 2013 19:58 To: Fred Zimmerman; geoengineering Subject: RE: [geo] RE: Geoengineering carries unknown consequences Hi Fred, "action with some degree of error is preferable to the likely consequences of inaction" as a general rule to apply everywhere, of course, that statement does not hold at all - and very obviously so. I can't speak on behalf of the author of course, but I suppose he would say something along the following lines, which I agree with: Thinking about action or inaction is often better than not thinking about action or inaction. There are, of course, many specific cases/hypothetical scenarios in all arenas where action is definitely preferable and many cases where action is definitely not preferable. To make the jump from thinking about action or inaction (vs. not thinking) to something closer to what you say for this specific issue: simply action or inaction, definitely requires a certain knowledge about the system. Here again I can't speak on his behalf, but I would believe the author himself would suggest that we don't have that knowledge, from what he says in his paper looking into the basic physics of the models. Best wishes, Simon ________________________________________________ Simon Driscoll Atmospheric, Oceanic and Planetary Physics Department of Physics University of Oxford Office: +44 (0) 1865 272930 Mobile: +44 (0) 7935314940 http://www2.physics.ox.ac.uk/contacts/people/driscoll ________________________________ From: Fred Zimmerman [geoengineerin...@gmail.com] Sent: 01 August 2013 19:36 To: Simon Driscoll; geoengineering Subject: Re: [geo] RE: Geoengineering carries unknown consequences How would you respond to the objection (which I am sure you have encountered frequently) that action with some degree of error is preferable to the likely consequences of inaction? --- Fred Zimmerman Geoengineering IT! Bringing together the worlds of geoengineering and information technology GE NewsFilter: http://geoengineeringIT.net:8080 On Thu, Aug 1, 2013 at 2:14 PM, Simon Driscoll <drisc...@atm.ox.ac.uk<mailto:drisc...@atm.ox.ac.uk>> wrote: And a link to the referenced paper: http://link.springer.com/article/10.1007%2Fs00382-013-1761-5 "Until now, climate model intercomparison has focused primarily on annual and global averages of various quantities or on specific components, not on how well the general dynamics in the models compare to each other. In order to address how well models agree when it comes to the dynamics they generate, we have adopted a new approach based on climate networks. We have considered 28 pre-industrial control runs as well as 70 20th-century forced runs from 23 climate models and have constructed networks for the 500 hPa, surface air temperature (SAT), sea level pressure (SLP), and precipitation fields for each run. We then employed a widely used algorithm to derive the community structure in these networks. Communities separate “nodes” in the network sharing similar dynamics. It has been shown that these communities, or sub-systems, in the climate system are associated with major climate modes and physics of the atmosphere (Tsonis AA, Swanson KL, Wang G, J Clim 21: 2990–3001 in 2008; Tsonis AA, Wang G, Swanson KL, Rodrigues F, da Fontura Costa L, Clim Dyn, 37: 933–940 in 2011; Steinhaeuser K, Ganguly AR, Chawla NV, Clim Dyn 39: 889–895 in 2012). Once the community structure for all runs is derived, we use a pattern matching statistic to obtain a measure of how well any two models agree with each other. We find that, with the possible exception of the 500 hPa field, consistency for the SAT, SLP, and precipitation fields is questionable. More importantly, none of the models comes close to the community structure of the actual observations (reality). This is a significant finding especially for the temperature and precipitation fields, as these are the fields widely used to produce future projections in time and in space." Best wishes, Simon ________________________________________________ Simon Driscoll Atmospheric, Oceanic and Planetary Physics Department of Physics University of Oxford Office: +44 (0) 1865 272930<tel:%2B44%20%280%29%201865%20272930> Mobile: +44 (0) 7935314940<tel:%2B44%20%280%29%207935314940> http://www2.physics.ox.ac.uk/contacts/people/driscoll ________________________________ From: geoengineering@googlegroups.com<mailto:geoengineering@googlegroups.com> [geoengineering@googlegroups.com<mailto:geoengineering@googlegroups.com>] on behalf of Simon Driscoll [drisc...@atm.ox.ac.uk<mailto:drisc...@atm.ox.ac.uk>] Sent: 01 August 2013 19:06 To: geoengineering@googlegroups.com<mailto:geoengineering@googlegroups.com> Subject: [geo] Geoengineering carries unknown consequences The physicists out there may have already seen this short article: http://www.physicstoday.org/resource/1/phtoad/v66/i8/p8_s3 (also copied down below) which may be of interest to group members. Best wishes, Simon +++ I read with interest David Kramer’s piece on geoengineering (Physics Today, February 2013, page 17<http://dx.doi.org/10.1063/PT.3.1878>). I must say, I am more alarmed by what the geoengineers in his report are proposing than by the climate changes that are taking place. I believe geoengineers are removed from scientific reality. They ignore the fact that the climate system and its components—clouds, hurricanes, and so forth—are highly nonlinear and thus very sensitive to the initial conditions and to changes in the parameters. Nevertheless, one could study the system’s response in a probabilistic way when certain parameters are changed or when we introduce fluctuations, if the relationships among all the components are known exactly. And here lies the whole problem with geoengineering. The formulation of the climate system and its components is only approximately known. More than 30 climate models are floating around in the climate community, and their predictions about general dynamics simply don’t agree with each other. In a recent publication,1<http://www.physicstoday.org/resource/1/phtoad/v66/i8/p8_s3#c1> we considered 98 control and forced climate simulations from 23 climate models and examined their similarity in four different fields (upper-level flow, sea-level pressure, surface air temperature, and precipitation). We found that except for the upper-level flow, the agreement between the models is not good. Moreover, none of the models compares well with actual observations. One person in the Physics Today story said that geoengineering may result in changes in various weather patterns, but nobody knows what the changes are going to be and how they will affect the climate system. If the warming in the Arctic is a big event to mitigate, then it will require a significant “geoengineering” effort. To me, that means significant changes will occur elsewhere. Who can say whether those changes will be less serious than those taking place now? How can geoengineers talk about modifying clouds and albedo when clouds are represented in the climate models as mostly linear parameterizations? Kramer’s report did not mention hurricanes, but geoengineers also propose to dissipate them. Hurricanes are unique in the climate system because they represent major self-organization. As physicists well know, self-organization occurs in dissipative systems in which energy is not conserved but instead is exchanged with the environment. Hurricanes involve huge amounts of energy. Scientists have little idea how the atmosphere and the ocean will be affected if that energy is not allowed to be exchanged. I would not have a problem with geoengineering if the physics and dynamics of the climate system were well known. Climate scientists have a good idea of the large-scale flow of ocean currents, but detailed measurements are not available. They know the basic physics of cloud formation and its thermodynamics but do not fully understand detailed cloud microphysics or the complex connections between climate and ecosystems. And with complex nonlinear systems, details are important. So we need to make an effort to improve our understanding of our climate system and its components before we try to operate on it. We can engineer a car or a plane because we know the underlying physics of motion, combustion, and flight, and we understand the role of every component. Can geoengineers say the same about climate? ________________________________________________ Simon Driscoll Atmospheric, Oceanic and Planetary Physics Department of Physics University of Oxford Office: +44 (0) 1865 272930<tel:%2B44%20%280%29%201865%20272930> Mobile: +44 (0) 7935314940<tel:%2B44%20%280%29%207935314940> http://www2.physics.ox.ac.uk/contacts/people/driscoll -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To unsubscribe from this group and stop receiving emails from it, send an email to geoengineering+unsubscr...@googlegroups.com<mailto:geoengineering%2bunsubscr...@googlegroups.com>. To post to this group, send email to geoengineering@googlegroups.com<mailto:geoengineering@googlegroups.com>. Visit this group at http://groups.google.com/group/geoengineering. 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