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Ranyl
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This graphic from this, article, http://www.skepticalscience.com/climate-models-accurate-when-reflecting-natural-cycles.html Derived from this paper, http://www.nature.com/nclimate/journal/vaop/ncurrent/full/nclimate2310.html Looking at how CMIP5 models with La Nina trends from 1998-2010 tend to reproduce observations in terms of temperature,are in the 5-95% range and the cooling seems to be due to a PDO pattern. "he models in phase with ENSO (Fig. 5a) exhibit a PDO-like pattern of cooling in the eastern Pacific, whereas the models least in phase (Fig. 5b) show more uniform El Niño-like warming in the Pacific." And the first graph in the figure is the PDO run and the paper shows that internal mechanisms can cause warming slow downs even with a strong forcing. Sorry I know slightly off topic however, However the second graphic is interesting and is actual observations, and what the anomalies are is the rate of warming per decade (K/Dec). It seems looking at it that the NH has continued to warm rapidly especially in North Pacific and Arctic, and that the SH has cooled, and seems a reasonably distinct north south divide. Just wonder if anyone here could shed any light on why this North warming South cooling is occuring? Has the AMOC sped up due to polar shift in SH westerlies pulling the Agulhas current around the horn of Africa and draining the Southern oceans of heat? Has the AMOC just sped up? but recent papers seem to suggest the opposite, although the warm water do seem to be penetrating further north. Just quite striking north south heating cooling divide and was just wondering what people's thoughts are, as sea ice south has increased and sea ice north as we know in rapid decline, so does have some relevance to cryosphere. Anyway if any has any suggestions or knows of papers that explain it thank you in advance.
Toggle Commented 7 days ago on ASI 2014 update 5: low times at Arctic Sea Ice
Sorry LRC linked to same paper as you just meant to link to the large fire occuring now.
Toggle Commented Jul 17, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
http://www.climatecentral.org/news/nw-fires-weather-climate-change-boreal-forests-17778 "The amount of acres burned in the Northwest Territories is six times greater than the 25-year average to-date according to data from the Canadian Interagency Forest Fire Center." http://www.climatecentral.org/news/nw-fires-weather-climate-change-boreal-forests-17778 And these size of fires are unprecedented in 10000 years, http://www.pnas.org/content/early/2013/07/19/1305069110 Is it me or are all these weather extremes, forest fires, melting getting a bit scary? Number of extreme has basically at least doubled since the 1970's in all areas around the earth. http://www.wmo.int/pages/prog/drr/transfer/2014.06.12-WMO1123_Atlas_120614.pdf The drought torn, conflict induced middle east? Permafrost melting more and more rapidly and burning as peat exposed. Wonder what things will be like when we reach 1.5C?
Toggle Commented Jul 17, 2014 on ASI 2014 update 5: low times at Arctic Sea Ice
"However, since they created a predictive model (they even made a prediction for 2013 minimum) I'm actually no longer sure what they did exactly to create that (absolute) predictive model based on de-trended data from melting ponds in May." Hi Rob, I think they took the correlation factors between sea ice extent and melt ponds in May from the year or years preceding the forecast year and forecast using that, so to do the forecast you need the CICE model May melt pond extent and the previous few years correlations I think? I presume there ins't a good enough correlation between the peak melt pond fraction to the September sea min. as it doesn't capture the early start as well and why they used integrated time and area extent series values. I also wonder what effect earlier forest and peat fires in Siberia and Alaska have on melt pond formation as a secondary driver akin to Greenland melt?
Hi Rob, "However, from a physical point of view, no "continued downward trend" without a cause." Isn't Arctic warming is the cause for the downward trend in mean September sea ice extent? And yes predicting the trend for September needs a physical value, however they de-trended the data, both sides, melt pond and summer sea ice extent. And thus aren't they looking at the natural variability left after the warming forcing, that is primary cause of the melt situation, is removed. Happy with the melt pond rationale for increasing etc, however that isn't the warming trend in the arctic and the warming forcing will increase melt ponds I'd of thought and why they detrended to get rid of that influence. I'm not really sure what you think I'm saying here. I'm not saying Arctic isn't melting and this is all natural variation in anyway at all, the arctic sea summer sea ice is already a goner some time soon directly due to the warming it is experiencing which is mainly from GHG warming (the WPAC has heated to highest levels for some reason too!) However the Nature paper is describing the influence of melt pond extent on September sea ice amount around the running mean, and thus a good parameter to define what can be expected that September for a given September mean. If I'd said 2024 instead when the running mean would be much lower, the melt pond extent % will still be a predictor for the ice loss around that new lower mean. And the lowering of the mean does have a direct mechanism driving it, the accelerated Arctic warming due to the huge impulse of GHG gases, indeed if don't stop using all fossil fuels by 2020 humanities civilizations future is then just a mistaken theory. However can anyone provide a link or insights into what effect the el-nino brewing may have?
Been lurking lots here and very interesting as always. On the melt-pond thing, isn't the melt area integrated throughout May an indication of the natural variance aspects of the sea ice minimum, i.e. its predicts how far away from, the current norm that end of September sea ice will, but does not take into account the continued downward trend is sea ice as they de-trended the data. Therefore the question is what is the new norm for 2012-2015, and the melt pond anomaly will indicate how far below of above that September will be. as the sea area is rapidly trending downwards for the same melt pond extent 2014 would end up lower than 2012, therefore there is a little extra melt in 2014 due to general sea ice loss trends for September. Therefore to get to the same actual ice loss as 2012, 2014 melt pond amount need not be quite as low (needs to very close though) as 2012, for same September low, if melt pond area same should go lower and if melt pond area larger should go much lower. I suppose the point is, is that the melt pond extent predicts the natural variation around the mean, but does not tell anything about the negative (and accelerating) trend for the September sea ice loss over the last decades. 2013 had a very low melt pond and probably represents the upper end of natural variability for sea ice loss around the current mean. The question is is where does 2012 lie, is that the new mean, the lowest possible, or just slightly low? Whatever the answer as the downwards trend should continue it shouldn't be long before a 2013 May set up will have a lower ice extent in September anyway, but at that point a 2012 melt pond set up will probably the first ice free Arctic summer? Anyway we'll see what happens but one for sure is that the downward trend is likely to continue and the melt season will continue to extend as we warm and therefore what ever the melt pond amount ice free summers are long away. What does an El-Nino do to arctic sea ice? As 1997 and 2014 similar in Nino data for date in year, will 1997's sea ice variance from the mean then, be an indication of what we can expect this year?
"With that ice stacked up over 3KM deep over wide areas of the island, it will take a very long time for the heat to get to it." Are you sure? Seems from this paper that all that hot melt water takes the latent and sensible heat to the centre of the ice sheet, meaning they will melt like microwaved butter from the inside out, they call it cryo-hydrologic warming of the internal and base of ice sheets. Basically heat gets into the ice sheet a lot faster than previously thought, and not in any melt models yet! Philips T. et al, "Evaluation of cryo-hydrologic warming as an explanation for increased ice velocities in the wet snow zone, Sermeq Avannarleq, West Greenland" Journal of Geophysical Research: Earth Surface. http://onlinelibrary.wiley.com/doi/10.1002/jgrf.20079/abstract
Toggle Commented Oct 2, 2013 on Pinpointing the minimum at Arctic Sea Ice
Seems there is a lot of solution denial here, there is no time for replace any energy system! Renewables don't save carbon there are all a carbon cost to give some future electricity and every sinlge once of the carbon will have to re-removed and What about the grid? And what about other ecological effects of renewables when we are in a mass extinction now being stressed further and further by global warming. 350ppm is a long long long way away and we need to stop emissions now. There needs to be a paradigm shift to something not known and not just of power supply, but of every thing to facilitate a transformation needed to actual stop using fossil fuels i.e. Political system, economic system (entirely), farming and so on..... Write of debt? Outlaw Interest? De-value money every year? Ban coal mining, oil mining, gas mining.. Use far far less power, everyone now. Start shouting that the situation is alarming! alarming ! alarming! And needs the sort of action that this scale of problem deserves. E.g Just never go to an airport again because you care!
Thanks Neven, alarming. Considering the degrees of change already becoming apparent, the multiple positve non linear feedbacks (sea ice, methane, ^H2O with temperature), the recent study showing how it takes a higher climate sensitivity to produce the changes being seen and it does seem that we are in for a significant amount fo warming in the next 100years. Wonder where the runaway feedback tipping point is and is the tipping potential dependent just on scale alone (temperature rise) or on rate and scale? It seems to me that from the video that there this a runaway tipping point of no return, which produces a new temperature target that we must stay below, or it truly is a scorched earth. Lets hope that at least can avoided, they are talking about a lot of methane, however the massive release of methane didn't seem to happen during the last deglciation, although as Hansen has postulated the Arctic is probaly already as hot now as then, just the melt hasn't been completed, which is sort of suggestive we might be going a fair amount hotter. It does seem as though the release of methane from continental self methane has been induced and it has just recently it has been shown that CO2 from the first few metres of permafrost is already going to be released whatever we do. Hansen says the things may get beyond adaptation due to sea level and weather events, yet it is already clear that the sea level and the potential scale of storm surges at New York aren't going to fall anytime soon, 1m sea level is the lower end of conservative chance by 2100 and therefore doesn't that mean New York really does have to be relocated sometime this century? We are going get least 20% more rainfall overall, but also concentrated into deluge events, meaning lots more flooding as is all already being seen. Therefore there must be another temperature taget that is beyond adaptation? ???1.8C is basically inevitable whatever we do now and considering what is already happening (especially America droughts) with 0.8C, that alone is going to take some major transformational changes to the way we do things to maintain a large vibrant civilization. The last time the world has a CO2 of 325-400ppm (most likely 350ppm) and a continental arrangement as today (but with a slightly dimmer sun), was the early Pliocene and the earth by most estimates then was 2-5C warmer, more likely 3-5C and that has to include all feedbacks playing out their parts over millenia. However 60-80% of the warming occurs, so even 350ppm means 1.8C to 3C and a sea level rise ovrall of 20-25M eventually, so all the major cities are going to have to be moved in the next few millenia. It strikes me therefore there needs to a clear target for CO2 aspirations. For me 400ppm max, target 350ppm asap. That is a tight carbon budget, but considering the alternative?? Interesting the Arctic's siesmic activity is incerasing?
"The 450 Scenario of the IEA’s World Energy Outlook 2011, which sets out an energy pathway consistent with a 50% chance of limiting the increase in the average global temperature to 2°C" 50/50 chance of avoiding 2C, well that's not reassuring. 2C lets think about that, that is another whole 1C warmer than now, just how far will the baseline mean for extreme heat events have shifted by then, we've already shifted by gone 1.5SD, so ~3SD, or 1:1000 years events every other year! And the models there using draw down carbon far to quickly, don't have good ozone representation, the lowest possible CO2 release for warming and no permafrost releases, so that 50:50 is a hopeful misinformation in any case. Not to mention a much delayed albedo acceleration as those AGW models don't melt the Arctic a smuch as now for another 30-50years at least. What emissions reductions do we need to have a 95% of avoiding going over 2C? And that still means 1.5C is a certainity! Peak oil for me is somewhat irrelevant, we need to stop using all fossil fuels now, not encourage people to look for more as they think they're running out. The only way of change is to adapt (mitigation included) everything to create a none growth fossil fuel free, equitable, eco-system enhancing,carbon sequestering and sustainable society and protect agiasnt the inevitable warming and extremes to come and face up to the tiny carbon budget (or shoudl I say debt) that we have. That means an adaptation transformation, which is hinted in the SREX report initial chapters and including the adaptation thread into every decision we make as Eileen Shea (NOAA) stresses in her talk here, http://www.youtube.com/watch?v=V1CySwdMW7w&feature=BFa&list=PL61B096B67AD0EE3E I now its a pipe dream but faced with the what is happening we might as well try to make it happen in anyway possible?
And what about the other stuff? Mining, biodiversity, mass extinction, pollution, waste, pesticides, nitrogen fertilizers (kept those carbon sinks up nicely), over exploitation of resources, population, migrations, food insecurity, water issues, and so on. Maybe it is time to consider using lots and lots less power? 350ppm isn't that safe and that means there is no carbon budget, and all electricity production at present needs CO2 emissions to make it, even renewables, and therefore the question I ask is how much more upfront CO2 can be risked to provide power? To get to 350ppm means a peak of 400ppm with optimistic CO2 cycle models, so that is ~3years of current emissions as the latest CO2 is 395ppm. Ah well, what do we do? Rise to the challenge and learn how to adapt to climate and to transform everything else to being fossil fuel free, sustainable, equitable and eco-system enhancing?
Toggle Commented Aug 11, 2012 on ASI 2012 update 9: stormy weather at Arctic Sea Ice
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Aug 11, 2012