Re: [geo] Arctic Agenda

[John Nissen]

Hi Dan, Cooling the Arctic is particularly important, because 6.  A whole ecosystem is dependent on the continued existence of the Arctic sea ice, with implications on the marine food chain. We don't know how large this risk is, but it could be very large. 7.  Cooling the Arctic should reduce rate of sea-level rise from the melting and sliding of Greenland ice sheet into the sea [1]. 8.  The loss of Arctic sea ice would result in loss of the driver of the global thermohaline circulation [2], with unknown repercussions for thousands of years hence. 9.  Warm water from the Gulf Stream is getting diverted to West Greenland [3] [4], which is cause destabilisation of ends of glaciers [5]. 10.  Cooling the Arctic could prevent massive release of methane from permafrost.  Again, we don't know how large this risk is, but it could be very large, if all carbon were released as methane, with global warming potential of 72 over 20 years [6]. Further advantages: 11.  If SRM works in the Arctic, it might then be considered for the Antarctic or globally.  (Though perhaps there are arguments to start in the Antarctic rather than Arctic - I don't know.) 12.  The danger of adverse side-effect on the ozone can be minimised by application of aerosol in early spring. 13.  By applying aerosol only in the Arctic, less aerosol is needed, so side-effects are minimised. Disadvantage (care of Bill Fulkerson) 1. Restoring sea ice would make mining for gas and oil more expensive (but perhaps that's a good thing, since the extraction could involve a lot of energy, hence not "green".) Debatable points (Alan Robock) 1. It won't solve the problem of global warming (so what - the aim is to halt regional warming in the Arctic?) 2. The country or countries involved with geoengineering might feel obliged to get agreement from the whole world.  (But UNFCCC Article 3 says countries which are able, should act to mitigate adverse effects for all mankind  [7]) 3. Effect on lower latitudes is currently unknown (but shouldn't we at least find out if there is any, and whether with positive or negative impact?) 4.  No technology has been demonstrated that can create an aerosol cloud in the stratosphere (but isn't that why we need some experimental trials?). Cheers, John [1] Note that the Greenland ice sheet may have contributed 1 to 2 metres to sea level rises at end of Eemian: http://www.nature.com/nature/journal/v404/n6778/full/404591a0.html There could have been more, but other ice fields might taken into account: http://www.sciencemag.org/cgi/content/abstract/311/5768/1751 This was at a time when Southern Greenland was forested: http://www.ncbi.nlm.nih.gov/pmc/articles/PMC2694912/?tool=pmcentrez [2]  Peter Wadhams found a marked weakening in 2005: http://en.wikipedia.org/wiki/Shutdown_of_thermohaline_circulation [3] http://www.dailykos.com/story/2010/1/6/822520/-Freak-Current-Takes-Gulf-Stream-to-Greenland [4] http://www.dailykos.com/story/2009/12/30/820607/-Warm-Atlantic-Water-Rapidly-Replacing-Arctic-Sea-Ice- [5] RGS Spring Bulletin, page 13: http://www.rgs.org/NR/rdonlyres/99F989E2-101D-4975-AC17-F1A22BED0363/0/BulletinSPRING2010FINAL.pdf [6]  http://www.ccrc.unsw.edu.au/Copenhagen/Copenhagen_Diagnosis_LOW.pdf The total amount of carbon stored in permafrost has been estimated to be around 1672 Gt (1 Gt = 109 tons), of which ~277 Gt are contained in peatlands. This represents about twice the amount of carbon contained in the atmosphere. [7]  UNFCCC Convention Article 3, points 1 and 3: http://unfccc.int/essential_background/convention/background/items/1355.php 1. The Parties should protect the climate system for the benefit of present and future generations of humankind, on the basis of equity and in accordance with their common but differentiated responsibilities and respective capabilities. Accordingly, the developed country Parties should take the lead in combating climate change and the adverse effects thereof. 3. The Parties should take precautionary measures to anticipate, prevent or minimize the causes of climate change and mitigate its adverse effects. Where there are threats of serious or irreversible damage, lack of full scientific certainty should not be used as a reason for postponing such measures, taking into account that policies and measures to deal with climate change should be cost-effective so as to ensure global benefits at the lowest possible cost... Efforts to address climate change may be carried out cooperatively by interested Parties. --- xbenf...@aol.com wrote: All: Preparing for the Asilomar conference, I summed up major points favoring doing aerosol cooling of the Arctic. Can others suggest further points? Feel free to dispute their importance, too. Gregory Benford STEPS TOWARD SAVING OUR ARCTIC GREGORY BENFORD Department of Physics & Astronomy University of California, Irvine        This paper proposes experiments to halt Arctic warming. The advantages of first attacking climate change in the Arctic by reflecting sunlight are several: 1.  The Arctic is the most endangered region, warming faster than other areas. 2.  The Arctic stratosphere is the lowest, beginning at about 38,000 feet (11.5 km). This places it within range of the most suitable aircraft for spreading aerosols, the in-flight refuelers. The tropical stratosphere is largely beyond range of these aircraft, so experiments there will demand fighter-class aircraft. The US has a large lead in such technologies, and economies of scale. 3.  The Arctic Council forms a natural group for managing such experiments. The US has many allies on the Council, and Russian objections can be met there. Eventual cooling targets that allow northwest passage in the summer can be negotiated as well, away from larger international bodies. 4.  Experiments can proceed from US territory. We have the best space technologies for diagnostics in the region. No treaties now govern the stratosphere. 5.  Arctic experiments done in summer will have minimal effects on lower latitudes, despite some diffusion and convection of aerosols. Rainfall effects in monsoons, etc, will be minimal. Costs of Arctic experiments (~$300 million) are far lower than tropical experiments (~$ several billion). -- 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=en.