A few comments.
1. Am CCing my colleague Jim Corbett, who wrote a bunch of the important papers on emissions from shipping, is an author of the latest paper mentioned her, and as worked with the IMO on this. Jim: any discussion on this tradeoff at IMO? 2. Some ships already dual fuel (bunkers and natural gas), where the NG is burned in and near port to comply with local air quality. 3. Numbers only work against bifurcated system if no policy to preserve or promote sulfur emissions in open ocean. 4. Work needed to estimate the ratio of climate forcing to heath impacts of S emissions as a function of the location of the emissions, this would allow where it make most sense to promote or restrict emissions. I will pitch this to atmo chemists at their Gordon Research conference this evening. 5. We don't just want to leave ship emissions as they are because we will need manage NOx even if we want S emissions. Both are big from ships. See Jim's paper: J. J. Corbett and P. S. Fischbeck, "Emissions from Ships," Science, vol. 278, no. 31 October 1997, pp. 823-824. 6. The idea that we can use the S for geo is likely irrelevant. There is ample S as H2S in sour gas either produced and re-injected or made into elemental S using Claus process. (There are many megaton-scale blocks of elemental S from this process in Alberta where I live, stunning yellow patches on the landscape.) -David ________________________________ From: [email protected] [mailto:[email protected]] On Behalf Of Alvia Gaskill Sent: August 20, 2009 1:07 PM To: [email protected]; geoengineering; Climate Intervention Subject: [geo] Re: The International Maritime Organisation's plans to warm the world The actual experienced level of sulfur in bunker fuels is now around 2.7%, so the reduction isn't going to be a factor of 10. And it will require a significant effort on the part of refiners to achieve the target levels, so some slippage is likely. I also doubt that ships will be equipped with high sulfur and low sulfur fuels, although some ships that do mainly transoceanic routes like container ships may be given waivers to use only high sulfur fuel in order to keep the aerosol levels up. At some point, however, the numbers work against such a bifurcated system and low sulfur will prevail, the other fuel simply no longer available in meaningful quantities. The reduction in negative forcing from tropospheric sulfate aerosols will continue as Paul Crutzen predicted. Not only will the contribution from shipping eventually become negligible, but the same will be true for coal and distillate fuels used on land and in air transportation. All told, the loss of these aerosols may be as much as 1.6W/m2 by 2050 if not sooner. The good news out of this besides the improvement in air quality is that more sulfur in the form of H2S and SO2 will become available for use in stratospheric aerosols if that approach is adopted. Regardless, the real global warming is just getting started. --~--~---------~--~----~------------~-------~--~----~ 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 -~----------~----~----~----~------~----~------~--~---
