Further to Mike,
I would like to draw also attention to terrestrial snow cover. Snow has increased due to less ice covered Arctic Ocean during the summers and autumn. This insulates air more from the ground. On the other hand, the amount of ground heat has increased as the soil beneath snow is warmer than in the past. The warmed grounds radiate, put out more heat, during the cold winter time where the snow coverage remains average thickeness. Thermal inertia of soil may be less than that of sea water and there is certainly little mixing, but some areas have active ground water that may produce variable heat output. Both the thickeness and area have increased, but so has the volatility of snow. The record Northern Hemisphere snow cover of February 2008 was quickly followed by record melts. As per the above, the terrestrial variability has become greater, more chaotic due to multiple variables having a greater say to the stability of the snow cover. The microbial activities have also kicked in a positive feedback in soil heat budget in some areas where a tipping point in this respect has been reached, the decay releasing also heat in systems. Kr, Albert > Date: Mon, 2 Nov 2009 13:29:13 -0500 > Subject: [clim] Re: Sea ice: beware of hype, uncertainty cut's both ways > From: [email protected] > To: [email protected]; [email protected] > CC: [email protected]; [email protected]; > [email protected]; [email protected] > > > Also please see > http://blogs.reuters.com/environment/2009/10/30/panic-at-2-am-the-search-for > -multiyear-arctic-ice/ > > Ice cover is not the only issue--ice thickness also matters for it takes an > extensive, pretty solid (i.e., very small or no leads) ice cover about a > meter thick or more (with a bit of snow on top) to insulate the winter > atmosphere from the ocean and allow ice surface temperatures to drop down to > -40 or lower so that the really cold winter air masses that create the > winter weather that we have depended on can form. > > Best, Mike > > > On 11/2/09 10:08 AM, "David Keith" <[email protected]> wrote: > > > A couple of points on sea ice: > > > > 1. There have been a bunch of hype-rich data-poor announcements recently > > that > > confidently predict very early dates for disappearance of summer sea ice. > > There is some good evidence that people are overinterpreting interannual > > variability as signal. The following is quite painful: it was the July 2009 > > compilation of forecasts every single one of which overestimated the actual > > sea ice loss in 2009. (I enclose a figure with the 2009 data added as an > > annotation. See the following for the original report: > > > > http://www.arcus.org/search/seaiceoutlook/2009_outlook/july_report/downloads/g > > raphs/JulyReport_JuneData_Chart.pdf > > > > I am deeply concerned about the rapidity of change in the Arctic, indeed > > unlike most people who talk about this I spent a fair amount of time > > traveling > > on skis high Arctic, but I'm a skeptical scientist and I know that > > uncertainty > > cuts both ways. I also am keenly aware that people tend to interpret noise > > as > > signal when it goes the way they expect. > > > > 2. Several folks on this list talk about the ice-albedo feedback as if it is > > not included in models. In fact this feedback is one of the central reasons > > for the polar amplification of predicted global warming and has been in > > models > > in various forms since the early 70s. In recent years the big focus has been > > improving dynamic (including ocean currents) sea ice models. Among the > > things > > typically not included are the (very uncertain) effect of warming permafrost > > on methane emissions, this is likely not a large omission as it's very hard > > to > > have methane emissions large enough to significantly change radiative > > forcing > > over half-century timescales. > > > > 3. It does appear that the IPCC underestimated the possibility of > > large-scale > > loss of the big ice sheets, I have run an expert elicitation > > (www.ucalgary.ca/~keith/elicitation.html > > <http://www.ucalgary.ca/~keith/elicitation.html> ) on the topic and our > > compilation of expert judgments (almost all of whom were in IPCC) shows that > > IPCC dramatically underestimated the risk. > > > > 4. One can make an argument that albedo geoengineering would be particularly > > appropriate for the Arctic both for the obvious reason that climate change > > impacts and responses are largest there, and because by increasing > > reflectivity geoengineering would be nicely countering the albedo feedback > > that decreases reflectivity. > > > > -David > > > > > > > > From: John Nissen [mailto:[email protected]] > > Sent: November 1, 2009 11:54 AM > > To: David Keith > > Cc: [email protected]; [email protected]; > > Ken > > Caldeira; Julian Norman; Mike MacCracken > > Subject: Re: [geo] ERL papers on line > > > > > > 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> > > > > 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 > > > > > > > > > > > > > > _________________________________________________________________ New Windows 7: Simplify what you do everyday. 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