On methane limitation, remember that human sources have elevated the methane concentration to near 1800 ppb from its preindustrial value of about 1000 ppb less, so there is potentially a lot that can be done to bring the elevated methane concentration back down, and it would have a very large climatic influence. As far as human sources, in the US the EPA inventory gives, as I recall, roughly the following source categories:
1. About 25-30% from fossil fuels‹and if we are going to phase these out, we should be able to get this down a good deal; 2. Another 25-30% from landfills and sewage treatment, etc.--and we know how to reduce these emissions 3. Something like 30-35% from agriculture‹and these can be partly controlled. In fact there are already efforts underway to suck in and separate the methane out in cattle feeding lots in California (and this can be done in barns as well) and use the methane for power (right now through combustion engines that emit NOx which troubles air pollution district officials) but perhaps soon into fuel cells. Other nations have different mixes, but also a lot of opportunities to reduce methane and we should do all that we can‹and whatever we can do will help keep temperatures down so help to slow the increase in emissions from thawing permafrost. Related to this, we also need to aggressively reduce emissions of black carbon and precursors to tropospheric ozone because those as well will bring down atmospheric concentrations forcing noticeably and quickly. In fact, the 21st century emissions of CO2 provide only about half of the 21st century warming influence of the emissions of all GHGs (i.e., methane and tropospheric ozone are the other most critical ones‹then halocarbons and N2O), so we simply must go after all GHGs aggressively. Limiting Arctic warming would help keep natural emissions from going up, but with humans causing an increase of about 1000 ppb, there is plenty of potential to do better. Mike On 11/14/09 9:33 AM, "Andrew Lockley" <andrew.lock...@gmail.com> wrote: > David, > > I have to take issue with your comments. The most worrying sources of methane > are distributed, natural sources, such as permafrost and clathrates. These > cannot be effectively controlled at present, and their role in AGW is likely > to increase as feedback effects kick in. > > Whilst recovering and remediating methane from sources such as landfill, etc, > is perfectly sensible, it can't hope to solve the problem of methane in the > long run. We need to address the presence of methane in the atmosphere, the > sources which create it and the potential failure of hydroxyl 'cleaning' > mechanisms - all at the same time. Complacency on methane could be our > undoing. I compare the situation to fighting off a dog whilst ignoring a > charging lion running straight for us. > > A > > 2009/11/2 David Schnare <dwschn...@gmail.com> >> Actually, it looks to me like it would be far more cost-effective to reduce >> methane first. It not only is a more potent greenhouse gas, but it has >> significant energy potential that can help pay for emissions reductions. Why >> not start there, even world wide, to include developing countries. About the >> only sources that cannot be captured and reused are from cows and the like >> and rice crops. >> >> David Schnare >> >> On Mon, Nov 2, 2009 at 10:27 AM, David Keith <ke...@ucalgary.ca> wrote: >>> It's not so blindingly obvious to me. Pretending that we can't cut emissions >>> is a way to hide from the moral implications of the choice we have made to >>> ignore the welfare of our grandchildren and keep pumping CO2 into the air. >>> >>> >>> >>> I agree with Alan Robock (among others) that we could begin making >>> substantial reductions in CO2 emissions with existing technology today. >>> >>> >>> >>> Electricity is the easiest place to start, it's 40% of global emissions and >>> you can mix and match solutions in a way you cannot with transportation >>> where we probably have to make a single choice about fuel substitution. >>> Large-scale wind power + gas backup, nuclear power, coal with CO2 capture, >>> and (in the right locations) central-station solar thermal could all be >>> built today at costs that we in the rich world could easily afford. (see >>> enclosed). >>> >>> >>> >>> Here's a blunt way to say it: there are at credible estimates (New England >>> Journal of Medicine) that more than 300 $bn/yr are wasted in transaction >>> costs in the US healthcare system. If you gave me that much money, and if I >>> was free to avoid political correctness (no solar PV on roofs), I think it's >>> reasonable that one could completely decarbonized the US electric power >>> system in a few decades. >>> >>> >>> >>> I am still optimistic that we will see real commitment to emissions cuts in >>> the rich world, and soon. I may be wrong, but in any case I don't claim any >>> special ability to judge political outcomes. >>> >>> >>> >>> It is very destructive when people from the technical community confuse >>> technical facts with judgments about values and politics. >>> >>> >>> >>> When someone like Peter Read (see below) says ³there is no way increasing >>> CO2 emissions can be significantly slowed any time soon² I think he really >>> means is that his political judgment is that the commitment to doing so will >>> not be made. >>> >>> >>> >>> However when people and the political community hear technical people say >>> can't be done they assume we mean that technically can't be done and that is >>> untrue and destructive. >>> >>> >>> >>> It's destructive because it hides the central moral choice: we could cut >>> emissions if we want to, we could have started decades ago when the >>> scientific warnings about climate change were first raised, but we decided >>> not to. It was a choice, implicit or not. A choice that, in effect, we cared >>> more about current consumption than we did about preserving our >>> grandchildren's chances to enjoy a climate like the one in which our >>> civilization developed. >>> >>> >>> >>> I think we need to develop the capability to geoengineer to manage the risk >>> of dangerous climate change posed by CO2 already in the air. That risk grows >>> with every added kilogram of carbon, and it cannot be eliminated by >>> emissions cuts even if we cut emissions to zero today. >>> >>> >>> >>> -David >>> >>> >>> >>> >>> >>> >>> From: Peter Read [mailto:pe...@read.org.nz] On Behalf Of Peter Read >>> Sent: November 1, 2009 3:23 PM >>> To: mmacc...@comcast.net; John Nissen; David Keith >>> Cc: Climate Intervention; Geoengineering; Ken Caldeira; Julian Norman >>> Subject: Re: [geo] Re: ERL papers on line >>> >>> >>> There's no way that increasing CO2 emissions can be significantly slowed any >>> time soon. There's 5 billion people out there that want the lifestyle they >>> see 2 billion Westerners enjoying on TV >>> >>> So the answer has to be to get 10 GtC / yr out of the atmosphere, and a bit >>> more so as to bring the level down. >>> >>> Do that and you can progressively replace the current flow of fossil fuel >>> with a flow of biofuel. >>> >>> A welcome prospect to those who worry about 'peak oil'. >>> >>> It doesn't need rocket science, just sensible policy and a bit of >>> organization. >>> >>> It's all so blindingly obvious >>> >>> Peter >>>> >>>> ----- Original Message ----- >>>> >>>> From: Mike MacCracken <mailto:mmacc...@comcast.net> >>>> >>>> To: John Nissen <mailto:j...@cloudworld.co.uk> ; David Keith >>>> <mailto:ke...@ucalgary.ca> >>>> >>>> Cc: Climate Intervention <mailto:climateintervent...@googlegroups.com> ; >>>> Geoengineering <mailto:Geoengineering@googlegroups.com> ; Ken Caldeira >>>> <mailto:kcalde...@stanford.edu> ; Julian Norman >>>> <mailto:julian.nor...@iop.org> >>>> >>>> Sent: Monday, November 02, 2009 9:50 AM >>>> >>>> Subject: [geo] Re: ERL papers on line >>>> >>>> >>>> Dear John‹A couple of comments: >>>> 1. Indeed, keeping the Arctic cold and keeping summer sea ice go hand in >>>> hand. So, yes, I certainly want to keep summer sea ice around (what would >>>> actually be helpful is to have thin sea ice in the winter so the heat held >>>> by the ocean could be conducted through the sea ice and radiated to space, >>>> making the ice thicker). >>>> 2. On the issue of the paper just dealing with solar radiation management, >>>> my talk in Copenhagen in March 2009 and the World Bank report that I >>>> prepared on geoengineering for the World Sustainability Report I had a >>>> fourth category devoted to reducing CO2, which I agree is also essential. >>>> This was not covered in the paper as the paper was long enough as it was >>>> and I am not as knowledgeable on that area, but I certainly agree we want >>>> to keep CO2 down. As long as global fossil fuel emissions are heading >>>> upward toward 10 GtC/yr and then higher, however, it is hard to see how >>>> pulling CO2 from the atmosphere is going to have enough of an effect to >>>> make a significant difference-we have to get emissions down to deal with >>>> CO2 related issues such as acidification, and keeping sea ice from melting >>>> is going to take geoengineering, at the pace we are going (the only other >>>> alternative is really cutting the non-CO2 GHG emissions and soot to zero >>>> quickly as their radiative forcing can go down faster than the rise in >>>> forcing due to rising CO2, at least for a short time. You can see my >>>> thoughts on dealing with short-lived GHGs at >>>> http://www.climate.org/PDF/MacCracken_Erice.pdf >>>> >>>> Mike >>>> >>>> >>>> On 11/1/09 1:53 PM, "John Nissen" <j...@cloudworld.co.uk >>>> <http://j...@cloudworld.co.uk> > wrote: >>>> >>>> Thanks for the reference to the Environmental Research Letters, David. >>>> >>>> Only Mike MacCracken's paper considers the context for geoengineering. If >>>> we are going to have to use geoengineering to tackle certain problems, how >>>> should we approach it. He considers three problem areas: >>>> 1) the warming of low-latitude oceans which contribute to more intense >>>> tropical cyclones and coral bleaching; >>>> 2) the amplified warming of high latitudes and the associated melting of >>>> ice that has been accelerating sea level rise and altering mid-latitude >>>> weather; >>>> 3) the projected reduction in the loading and cooling influence of sulphate >>>> aerosols, which has the potential to augment warming sufficient to trigger >>>> methane and carbon feedbacks. >>>> >>>> I would suggest that the amplified warming of (2) has the potential to >>>> trigger massive methane discharge (and associated positive feedback on >>>> global warming) of (3) as well as the potential to trigger rapid sea level >>>> rise. The retreat of Arctic sea ice is part of the warming amplification >>>> process, so it is crucial to prevent its summer disappearance. Do you >>>> agree, Mike? >>>> >>>> If you agree, then the importance of this (i.e. preventing Arctic sea ice >>>> summer disappearance) makes the arguments against geoengineering in the >>>> other papers seem rather irrelevant! >>>> >>>> Note that Mike has only considered the problems that could be addressed >>>> with SRM geoengineering. If we consider problems such as ocean >>>> acidification, and addressing them with techniques such biochar, then the >>>> arguments in the other papers against geoengineering seem irrelevant to the >>>> point of absurdity - but then perhaps the arguments were directed at SRM >>>> geoengineering alone. >>>> >>>> Cheers from Chiswick, >>>> >>>> John >>>> >>>> --- >>>> >>>> David Keith wrote: >>>> >>>> >>>> >>>> Folks, >>>> >>>> >>>> >>>> There is a set of papers on geoengineering on line at Environmental >>>> Research Letters. Ken Caldeira and I served as editors of this special >>>> issue. More papers and a editorial will be added later. >>>> >>>> >>>> >>>> Cheers, >>>> >>>> David >>>> >>>> >>>> >>>> >>>> >>>> http://www.iop.org/EJ/abstract/1748-9326/4/4/045101 >>>> >>>> >>>> >>>> Focus on Climate Engineering: Intentional Intervention in the Climate >>>> System >>>> >>>> 2009 Environ. Res. Lett. 4 045101 doi: 10.1088/1748-9326/4/4/045101 >>>> <http://dx.doi.org/10.1088/1748-9326/4/4/045101> >>>> <http://www.iop.org/EJ/help/-topic=abstract/abstract/1748-9326/4/4/045101> >>>> >>>> >>>> Geoengineering techniques for countering climate change have been receiving >>>> much press recently as a `Plan B' if a global deal to tackle climate change >>>> is not agreed at the COP15 negotiations in Copenhagen this December. >>>> However, the field is controversial as the methods may have unforeseen >>>> consequences, potentially making temperatures rise in some regions or >>>> reducing rainfall, and many aspects remain under-researched. >>>> >>>> >>>> This focus issue of Environmental Research Letters is a collection of >>>> research articles, invited by David Keith, University of Calgary, and Ken >>>> Caldeira, Carnegie Institution, that present and evaluate different methods >>>> for engineering the Earth's climate. Not only do the letters in this issue >>>> highlight various methods of climate engineering but they also detail the >>>> arguments for and against climate engineering as a concept. >>>> >>>> >>>> Further reading >>>> Focus on Geoengineering at >>>> http://environmentalresearchweb.org/cws/subject/tag=geoengineering >>>> IOP Conference Series: Earth and Environmental Science is an open-access >>>> proceedings service available at www.iop.org/EJ/journal/ees >>>> <http://www.iop.org/EJ/journal/ees> <http://www.iop.org/EJ/journal/ees> >>>> >>>> >>>> Focus on Climate Engineering: Intentional Intervention in the Climate >>>> System Contents >>>> >>>> >>>> Modification of cirrus clouds to reduce global warming >>>> <http://www.iop.org/EJ/abstract/1748-9326/4/4/045102> >>>> David L Mitchell and William Finnegan >>>> >>>> >>>> Climate engineering and the risk of rapid climate change >>>> <http://www.iop.org/EJ/abstract/1748-9326/4/4/045103> >>>> Andrew Ross and H Damon Matthews >>>> >>>> >>>> Researching geoengineering: should not or could not? >>>> <http://www.iop.org/EJ/abstract/1748-9326/4/4/045104> >>>> Martin Bunzl >>>> >>>> >>>> Of mongooses and mitigation: ecological analogues to geoengineering >>>> <http://www.iop.org/EJ/abstract/1748-9326/4/4/045105> >>>> H Damon Matthews and Sarah E Turner >>>> >>>> >>>> Toward ethical norms and institutions for climate engineering research >>>> <http://www.iop.org/EJ/abstract/1748-9326/4/4/045106> >>>> David R Morrow, Robert E Kopp and Michael Oppenheimer >>>> >>>> >>>> On the possible use of geoengineering to moderate specific climate change >>>> impacts <http://www.iop.org/EJ/abstract/1748-9326/4/4/045107> >>>> Michael C MacCracken >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> >>>> No virus found in this incoming message. >>>> Checked by AVG - www.avg.com <http://www.avg.com/> >>>> Version: 8.5.423 / Virus Database: 270.14.43/2474 - Release Date: 11/01/09 >>>> 07:38:00 >>>> >>>> --~--~---------~--~----~------------~-------~--~----~ >>>> You received this message because you are subscribed to the Google Groups >>>> "geoengineering" group. >>>> To post to this group, send email to geoengineering@googlegroups.com >>>> To unsubscribe from this group, send email to >>>> geoengineering+unsubscr...@googlegroups.com >>>> <mailto:geoengineering%2bunsubscr...@googlegroups.com> >>>> 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 geoengineer...@googlegroups.com. >>> To unsubscribe from this group, send email to >>> geoengineering+unsubscr...@googlegroups.com. >>> For more options, visit this group at >>> http://groups.google.com/group/geoengineering?hl=. >>> -- You received this message because you are subscribed to the Google Groups "geoengineering" group. 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