Folks I am not getting this, and yet I am close to it. My office is down the hall from the GEOS-Chem group that produced these papers. We collaborate in that Debra Weisenstein works with me and with that group is doing modeling for geoengineering and looking into improvements to the GEOS-Chem stratospheric chemistry.
1. Can someone tell me exactly what would be tested here? Climate response? Aerosol radiative forcing? 2. Is there a sensible reason why you one would prefer troposphere SO2 for geoengineering if one wanted to do it? Recall that trop SO2 now is linked to about 1 million air pollution deaths per year globally as well as acid rain etc. 3. The idea that cutting tropospheric SO2 pollution is a form of geoengineering would seem to me to extend the definition of geoengineering to mean, in effect, "any human action that may alter the climate". I doubt this definition will help clarify debate. Yours, David From: [email protected] [mailto:[email protected]] On Behalf Of Hawkins, Dave Sent: Tuesday, May 01, 2012 10:51 AM To: [email protected]; [email protected] Cc: [email protected] Subject: RE: [geo] Regional SRM experiment Nathan, The CEC report you link to was useful but is now dated. Much more current information on SO2 emissions (up to and including 4th quarter 2011 for the power sector) is available thanks to the 1990 Clean Air Act, which required SO2 continuous emission monitors on all coal power plants in the 48 contiguous states of the US. A handy spreadsheet of national SO2 emission trends from 1980 to 2010 can be found here: http://www.epa.gov/airmarkets/progress/ARPCAIR_downloads/CAIR_ARP_2010_data_1.xls This spreadsheet also includes data disaggregated by state and by month. Other pages at the airmarkets link above will get you access to hourly emissions and operational data from all significant US coal power plants. (FWIW, getting the rules in place to require these data to be reported at all, much less to be reported electronically and accessible to anyone, required quite a lot of persistent advocacy.) The national SO2 trends are informative as to the scale of the reductions from more than 17 million tons of SO2 from the power sector in 1980 to about 5.2 million tons in 2010. The combination of EPA's new transport rule and toxics rule will cut the load further to about 2 million tons in the 2015-2016 time frame. http://www.epa.gov/ttn/ecas/regdata/RIAs/matsriafinal.pdf, Table 3-4. But the additional instrumentation I was referring to in my email was not emission monitoring data (as the above information indicates, we now have that pretty well in place in the US for the power sector). Rather, I am thinking of high resolution data of the characteristics of the atmosphere that might change as these additional emission reduction occur. I don't know enough to have anything in particular in mind but I imagine there are some on this list who could identify the data sets they would like to have to fully characterize the forcing and other aspects of the changes brought about by the large SO2 reductions from 1980 to date and from the large additional percentage reductions that will occur over the next 3-5 years. For example, how linear or nonlinear are the forcing responses to a given tonnage reduction in fine particle precursors or a given ppm change in fine particle concentrations. My hunch is that the localized impacts will differ depending on the baseline atmospheric conditions on which the emission changes are imposed. Knowing more about that might be nice to help improve modeling estimates of the local/regional impacts of SRM experiments. David From: [email protected]<mailto:[email protected]> [mailto:[email protected]] On Behalf Of Nathan Currier Sent: Tuesday, May 01, 2012 11:38 AM To: [email protected]<mailto:[email protected]> Cc: [email protected]<mailto:[email protected]>; Geoengineering Subject: Re: [geo] Regional SRM experiment Hi, David - I fully agree with that, and actually used that same MIT paper in something I wrote up for the group AMEG recently. In fact, if you look at table 3.3 in this - http://www.findthatfile.com/search-19564999-hPDF/download-documents-4876_powerplant_airemission_en.pdf.htm you'll also see that of the top 10 highest SO2-producing power plants in the US - and these are the only US plants that put out over 100,000 mt SO2/yr each (and their inputs get smaller pretty quickly as the sizes decrease) - 7 of the 10 are just in Penn & OH alone. On the "dot map" of US SO2 emissions in the attached, these two states are almost invisible, being swallowed up by a big dot for all the SO2 there. I don't have a figure for the average loading of the two states, but it could be roughly ascertained pretty easily by EPA's SO2 trends map. Anyhow, just a study of the SO2 in these two states, Penn and Ohio, would be the most helpful, and in fact possibly even more useful *because* it's in the troposphere, I feel. But it needs to be done very soon, as the new CAIR program rules are apparently going to reduce all of this a good deal more in the next 3-4 yrs, I believe. All best, Nathan On Monday, April 30, 2012 2:44:33 PM UTC-4, David Hawkins wrote: The largest insight I draw from this paper is the reminder that there are fairly large-scale activities going on right now that might provide useful information regarding SRM if we had systems set up to monitor resulting changes. This paper documents one of them - the large reversal of sulfate loadings in the eastern half of the US, mostly occurring since the 1990 Clean Air Act was passed. And those reductions will continue. Rules promulgated by EPA in the last six months will required millions of tons more of SO2 and NOx reductions over the next 3-5 years. It would be nice to do a rapid assessment of what additional instrumentation might produce even more useful information, relevant to the many unanswered questions about SRM. To be sure, most of these reductions are occurring in the troposphere and so may not be directly applicable to SRM in the stratosphere. Still, I imagine there could be useful information to be gathered. It might be much easier to get governments to devote some money to such an enhanced measurement effort than to try to stand up some new "geoengineering program." From: [email protected]<mailto:[email protected]> [mailto:[email protected]<mailto:[email protected]>] On Behalf Of Mike MacCracken Sent: Sunday, April 29, 2012 8:38 PM To: Geoengineering Subject: Re: [geo] Regional SRM experiment Hi David-Very interesting, and just why it might be possible to do something to limit warming in an area like the Arctic, which, as was documented over and over again at the Montreal IPY meeting last week, is changing very fast. Mike MacCracken ******** On 4/28/12 10:06 AM, "David Hawkins" <MailScanner has detected a possible fraud attempt from "[email protected]" claiming to be [email protected]<http://[email protected]>> wrote: Climatic effects of 1950-2050 changes in US anthropogenic aerosols - Part 2: Climate response http://www.atmos-chem-phys.net/12/3349/2012/acp-12-3349-2012.pdf Reduction in air pollution from coal fired power stations due to environmental regulations since the 1980s has increased regional global warming in the Central and Eastern United States. Climate scientists from the Harvard School of Engineering and Applied Sciences (SEAS) found that particulate pollution, particularly from coal fired power stations, caused a global warming hole, or a large cold patch reducing temperatures by up to 1 degree C in the region, particularly lowering maximum temperatures in Summer and Autumn. Since I have spent a good deal of the past several decades advocating for rapid deployment of particle reducing techniques, I guess I can be tagged as an inadvertent geoengineer. :>) Sent from my iPad -- You received this message because you are subscribed to the Google Groups "geoengineering" group. To post to this group, send email to [email protected]<mailto:[email protected]>. To unsubscribe from this group, send email to [email protected]<mailto:geoengineering%[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 view this discussion on the web visit https://groups.google.com/d/msg/geoengineering/-/PRIGiFXTufkJ. To post to this group, send email to [email protected]<mailto:[email protected]>. To unsubscribe from this group, send email to [email protected]<mailto:[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]<mailto:[email protected]>. To unsubscribe from this group, send email to [email protected]<mailto:[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.
