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Comments 60001 to 60050:

60001. KR at 01:01 AM on 18 April 2012
       Return to the Himalayas
       Steve Case - Sudden floods after rainfall are not helpful for agriculture, as most of the runoff is simply lost downstream. Steady water supply throughout the summers requires significant snowpack or glacier melt throughout the year. Declines in that late season water will affect huge agricultural areas. [Source]
60002. Tom Curtis at 00:54 AM on 18 April 2012
       Return to the Himalayas
       Steve Case @34, you are quite correct that the flow of the river is a function of precipitation. Essentially, if all the precipitation is rainfall, it is a function of the average precipitation over the preceding week or so, with run off being delayed by vegetation. With very heavy precipitation, you get a greater proportion of run off, and hence a more immediate response to precipitation but the idea is valid. With snow pack, run off in the spring is a function of precipitation during the preceding winter, plus the precipitation during spring. In most river systems, by summer most of the snow will have melted, so river flow will be a function of summer rainfall. With glaciers, runoff is a function of precipitation averaged over several preceding years or even decades. Consequently, where you have heavy winter precipitation and light summer and spring precipitation, if precipitation is as rain, you will have flooding in winter, while in spring and summer the river will run low. With snow pack fed rivers, you will instead have flooding in spring, with winter and summer river levels being low. While with glacier fed rivers you will have near constant river flows throughout the year, with a peak in summer due to the faster rate of melting with summer temperatures. Specific situations will of course vary based on specific details of geography and meteorology in the area; but the basic pattern will hold. Packed snow is known to be permeable to air, both from the well known survival trick of burying yourself in snow to stay warm. If the snow was not permeable, that would not be a survival trick, but an invitation to death by suffocation. Further, studies related to measuring the trapped atmosphere in ice cores have measured the permeability of the firn to air, and found it is still permeable for up to 100 years (in the case of the South Pole). How quickly it becomes impermeable will depend on the rate of deposition of new snow, and hence the rate of compression of the firn, but periods in excess of 30 years are still common even in areas of very heavy deposition. Consequently the assumption that seasonal snow pack is still permeable to air is very safe. Finally, you say repeatedly that it will come down to the rate at which snow and ice melt. That formulation is, however, nonsensical. Snow is just a particular form of ice. What is relevant are the particular details of heat transfer, and how it effects the rate of ice melt given the different structure of snow and ice. Air is an excellent insulator. Consequently in cold weather, the many air spaces in snow will help insulate the inner layers from warming due to conduction or radiation on the outer layers. Without the air spaces, ice blocks have no such insulation. Consequently, in cold air conditions ice blocks heated by conduction or radiation will melt relatively faster. Against this, the snow has a larger surface area for a given mass which would encourage more rapid melting. Apparently in late winter and early spring with snow still on the ground, the balance of extra surface area vs better insulation is unfavourable for loosely packed snow, but favourable for densely packed snow. In April and May, however, the warmer air will penetrate the snow through those air gaps, hastening melt rather than retarding it. Consequently, if you carried out the same experiment in each month of the year, you would get different results in each month. And your experiment ignores the obvious facts that glaciers have a very large mass (and hence heat capacity) per unit surface area, while snow which is scattered thinly over the side of the mountain has a very large surface area per unit mass. If you are serious about your experimentation, you need to first control air temperature and mass and change surface area to see what effect that has. You then need to control for surface area and mass, and change air temperature and see what effect that has. Until you do so, your experiment is irrelevant, and certainly does not provide evidence that you can set against the observations of hydrologists on the actual impact of glaciers and snow packs of flow rates in rivers.
60003. Michael Whittemore at 00:34 AM on 18 April 2012
       New research from last week 15/2012
       I always dislike when people say that Al Gore was not telling the truth in his movie regarding high sea rise. He clearly explains that West Antarctica could rapidly melt and that Greenland could slip into the ocean. All I see in the peer review, is paper after paper of Greenland lakes disappearing and West Antarctica breaking up..
60004. Steve Case at 00:18 AM on 18 April 2012
       Return to the Himalayas
       Tom, Over time, measured in years, the flow in the river of any watershed is a function of the precipitation that falls in that watershed. The presence of a glacier ultimately has nothing to do with it. If the glacier is advancing year to year, the flow will be less than precipitation. If it's receding, the flow will be more. If the glacier is static or there is no glacier then flow will the same as precipitation. Those four cases are all minus evaporation. Packed snow permeable to air? Well, that's an assertion. As I've said a few times now, this whole thing will revolve around the difference in melt rate between ice and snow.
60005. Tom Curtis at 00:04 AM on 18 April 2012
       Return to the Himalayas
       Steve Case @33, you are ignoring the fact that snow pack comes in drifts of a few feet thick while glaciers are tens of meters thick. The result is that relative to snow pack, the glaciers have a much larger volume relative to surface area which accounts for their slow melt rate. I should also note that snow pack, even thickly packed snow is permeable to the air. That is of little consequence when air temperatures are below freezing, but for temperatures significantly above freezing, I strongly suspect it will result in the packed snow melting faster than the ice of the same mass.
60006. Steve Case at 23:47 PM on 17 April 2012
       Return to the Himalayas
       skywatcher #30

       You wrote:

       ...The ice cube is a reservoir that lasts through the dry season, holding back the precipitation that fell earlier in the year and gradually releasing it through the dry season. Snowpack is a much weaker and less stable form of this, often diappearing quite quickly in the melting season ...

       I said in my first post that this discussion would boil down to the difference in melt rate between ice and snow. I've been making this argument on different boards for some time now and I always wind up dealing with assertions like yours above. Last year I even did some crude experimentation:

       
       
       I got an "It depends answer" Packed snow outlasted the ice and fluffy snow does not.

60007. Kevin C at 23:46 PM on 17 April 2012
       2012 SkS Weekly Digest #15
       LarryM: There's a trivial proof that climate is not chaotic, and indeed is predictable. Isaac Held's presentation is elegant.
60008. Riccardo at 23:24 PM on 17 April 2012
       Global Warming in a Nutshell
       davpaf "doesn’t any material with a temperature above absolute zero, radiate heat?" A black body radiates following the Stefan-Bolzmann law. You need to multiply it by ε, the emissivity, for any real substance. If ε is zero, or in the frequency range where it is zero, so will be the radiation flux. Then the answer to your question is "more or less", depending on ε.
60009. tmac57 at 23:06 PM on 17 April 2012
       Newcomers, Start Here
       Tom-Yes,thanks,I had already read Tamino's post.I thought that it could have been a bit more comprehensive,but maybe it doesn't really deserve that much attention.It does appear that the denial machine is making quite a bit of noise about it,so I thought more push back from the science side might be warranted.
60010. Tom Curtis at 22:31 PM on 17 April 2012
       2012 SkS Weekly Digest #15
       Alexandre @24, that a cooler object can contribute to the more rapid, or greater heating of a warmer object is one of the easiest home experiments you can conduct. It is in fact, as easy as putting on a lid: For an alternative take, we can check out Matt. To fully satisfy the "skeptics" we would need two thermometers, one in the water and one on the lid to show that the lid is cooler (the use of hands to determine temperature not being recommended). I discuss the relevance, and other examples here. This experiment has additional benefits. It teaches you how to save water, money and CO2 emissions.
60011. Alexandre at 21:52 PM on 17 April 2012
       2012 SkS Weekly Digest #15
       Tom Curtis at 09:43 AM on 17 April, 2012 Indeed, an experiment has to be sufficiently controlled to produce any meaningful result. But I still think the education provided by SkS could greatly benefit from experiments, even simple ones. Questions like "can a cooler object affect the temperature of a warmer object?" could be greatly assisted, or even resolved, with an experiment, saving patience and time from all parties involved. I confess I don't have the time or knowledge to provide concrete examples, though. It's just a thought.
60012. Steve Case at 21:52 PM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       Rob Painting, Yes, I noticed that CU's Sea Level Research Unit put out a new release yesterday, and that graph I posted above would now look like: http://i40.tinypic.com/a1ppy.jpg
       Moderator Response: [DB] This thread is abour Cliff Ollier: Swimming In A Sea of Misinformation; if you wish to pursue your long-standing skepticism of SLR, please take it to one of the SLR-specific threads. Those who wish to engage Steve further on this, please do likewise.
60013. bath_ed at 20:23 PM on 17 April 2012
       Return to the Himalayas
       Steve Case#16: "the IPCC tells us that in a warmer world there will be more precipitation." Rather than arguing from first principles, it would be better to see if you can find any peer-reviewed studies that support your opinions. The predicted effects of climate change are well studied and the conclusions don't generally match yours. Your starting point is correct, that a warmer world also tends to be a wetter world *in general* and the Earth has *in general* dried as it has cooled in the Cenozoic (with the emphasis on “in general”). However, things are not quite so simple as to be able to conclude from that the effects will be beneficial to humanity. There are a number of other, complicating, factors that make the picture less rosy. First of all, where will the extra precipitation fall? Not everywhere will receive more rain – some will receive less. If, as is predicted, already wet regions receive more rain and snow while dry ones, especially in the subtropics, receive less, that would be extremely damaging for agriculture. It is predicted that precipitation will increase in the equatorial and sub-polar regions which are generally regions of excess moisture but decrease in the subtropics, where most of the world’s arid and semi-arid regions are found. Secondly, as temperature rises so does water loss and so more rainfall is needed. Would any increase in precipitation be sufficient to compensate for increased water loss? Think of say England, generally a ‘green and pleasant land’ where crops grow without irrigation, naturally covered in woodland (now mainly cleared). London has an average annual rainfall of 602mm, but is in world terms not exactly a hot city. By comparison, in tropical regions, around 1800mm of rainfall is needed per year to support woodland growth where the trees do not need to drop their leaves for part of the year for lack of water. At equatorial temperatures 602mm of rainfall wouldn’t go far and there would be many brown, parched months. Thirdly, one needs to think of when in the year the precipitation comes. Part of the reason for England’s greenness is that the rainfall is distributed fairly evenly through the year. If it mainly fell in the winter half of the year with little in the summer, the picture would be very different. Models of climate change predict greater seasonality of rainfall. Indeed, studies of the Palaeocene-Eocene Thermal Maximum (PETM), a period of extreme global warming thought to have been brought about by massive greenhouse gas release, show evidence of greatly increased seasonality with long dry periods followed by violent downpours. At the height of the PETM in the Bighorn Basin of Wyoming moist woodland was replaced with seasonally dry, open forest, similar perhaps to that found today in parts of Central America. Fourthly, if some regions become more suitable for agriculture and others less there are many associated problems even if there is little or no net change (or even a net positive change). Imagine if agriculture were to fail in say Kenya but open up new possibilities in Russia. Would it be possible for Kenyan farmers to simply up sticks and move to Russia? Would the Russians welcome them? Would they adapt? Or would we just decide that the Kenyans’ loss was balanced by the Russians’ gain and therefore famine in Kenya didn't matter because there were bumper harvests in Russia? I think you can see that the problem wouldn’t be trivial.
60014. davpaf at 19:53 PM on 17 April 2012
       Global Warming in a Nutshell
       Ok, so by equating TS and TE, one assumes TS is based on an existing atmosphere (affecting the amount of incoming solar radiation, as stated by clouds, dust, ozone) and TE is based only on the earth surface radiating into space, not the atmosphere. Shouldn’t strictly speaking all GHG effects be also removed from the TS part, I mean in this way it seems a bit inconsistent? One more question, doesn’t any material with a temperature above absolute zero, radiate heat? So if say one puts a parcel of air into space, it will eventually cool down. I understand that GHG, have specific bands of emission/absorption characteristics for specific radiation wavelengths, which oxygen/nitrogen don’t have. But both must be radiating if they have a temperature, right? Thanks.
60015. funglestrumpet at 19:34 PM on 17 April 2012
       2012 SkS Weekly Digest #15
       Issue of the week My biggest problem with the whole issue of AGW is the 'A' bit. The opinion seems to be that if the current warming we are experiencing were not anthropogenic in origin, all would well. I find that utter nonsense, and consider that we on this side of the fence do great harm by concentrating on that aspect of the problem. Perhaps I have it wrong, but from my perspective if the current warming were due to the Sun, say, then the need to reduce CO2 emissions would be all the more urgent, seeing as such an increase in solar output would be unexpected and not in line with how we expect the Sun to behave. Such unexpected behaviour would mean that we would be unsure whether the warming was going to continue indefinitely, stabilize at some point, or was just the ‘up’ part of a new and previously unknown cycle that was soon going to reverse itself and thus become a cooling phase. Until we were able to determine which of the options was correct (and quantify, if possible, the extent of the warming we were going to experience), it seems to me utter folly not to act, and act urgently, to do whatever we could to combat the warming induced by the increased solar radiation. Obviously, increasing albedo by painting all roofs white and growing flora that had lighter coloured, or shiny, foliage would help. So too would reducing CO2 emissions. In fact, so long-lived is atmospheric CO2 it would surely have top priority. I would find refusing to support action to combat the warming an act of treason against the human species, as indeed do I see the behaviour of all current members of the denialati, some more than others, in fighting CO2 induced warming. It is no defence that a very small number of scientists do not think that the level of warming will be as high as others. Until they can prove their case conclusively, we are obliged to go with the majority of scientists (as Galileo did with his fellow scientists, with emphasis on the word ‘scientists’). As for action by sks, or lack of it, I think that this site pays far too little attention to tipping points. In fact it almost seems to be a side issue, yet crossing a tipping point – always silently – might commit our offspring to dire conditions. Again, perhaps I am wrong, but I don’t think that the public is as aware as they should be of the danger that crossing a tipping point brings. There is a YouTube video of a car on a road covered in black ice. The driver crawls very cautiously at less than walking pace over the brow of a gentle hill on a housing estate somewhere or other. The driver obviously becomes aware, too late, that they have crossed a tipping point past which they cannot slow down. The car proceeds down the hill, wheels locked, until it hits a parked car. Am I wrong in thinking that we, as a species, are in a ‘car’ called planet earth that is creeping towards the brow of an icy galactic hill and the time is nigh, if not already in the past, where we will not be able to slow down, or stop progress to circumstances where planet earth will not support our descendants in anything like the projected population numbers soon to be upon us, not to mention what will happen to those that survive. The public are just not aware of that there is even a hill, let alone the danger of crossing its brow. The question in my mind is not ‘if’ the population will wake up to the danger of climate change, but ‘when’ it will, and whether the time that it does will be too late to act in any meaningful way. I will only get a small amount of pleasure from the fact that the prominent members of the denialati will be in grave danger if the public rise up in the way they have in the past, such as how they did in forming lynch mobs against paedophiles in the U.K. That will be their problem; my problem will be concern that perhaps I could have done more.
60016. CBDunkerson at 19:29 PM on 17 April 2012
       Global Warming in a Nutshell
       davpaf wrote: "Wouldn't this be effectively the representation of a planet system without an atmosphere?" If the atmosphere were composed entirely of gases which are 'transparent' to outgoing radiation (i.e. if all 'greenhouse' gases were removed) then it wouldn't matter... an atmosphere 100% transparent to all outgoing radiation is the same as no atmosphere at all for this purpose. That said, there are a lot of things in the atmosphere (e.g. dust, ozone) which block incoming radiation. Thus, if Earth had no atmosphere at all the incoming radiation and TS would be higher... at that, if we removed all GHG that'd mean no clouds, a correspondingly lower albedo, and thus higher TS (with or without an atmosphere). Anyway, the takeaway message is that GHG are the only reason TE does not equal TS - irrespective of any changes in the value of TS due to linked factors.
60017. davpaf at 18:37 PM on 17 April 2012
       Global Warming in a Nutshell
       Morning, OK, I think I also got a bit mixed up with CO2 and all the other GHG's in this thought experiment and after reading the quotes from the papers again and your comments, I am a bit clearer I think So would it be correct to say then, that in a situation without any GHG's, TS = TE, which would actually mean, the complete atmosphere is not active in radiating to space, only the surface. Wouldn't this be effectively the representation of a planet system without an atmosphere?
60018. Rob Painting at 18:13 PM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       Steve Case - it will sure be interesting to see how quickly sea level rises should an El Nino begin to develop. All that water temporarily held on land will drain back into the ocean. We'll get a better idea then, but I do note that AVISO has updated their figure; the 'speed bump' is getting steeper.
60019. skywatcher at 14:10 PM on 17 April 2012
       Return to the Himalayas
       #30 - many of these regions are dry for extended periods of the year. With a glacier present upstream, there's a water supply all year round, even in long dry periods. The ice cube is a reservoir that lasts through the dry season, holding back the precipitation that fell earlier in the year and gradually releasing it through the dry season. Snowpack is a much weaker and less stable form of this, often diappearing quite quickly in the melting season, leaving you with no water reservoir. Remove the ice cube altogether, and your river flow is much less reliable in the dry season. you might have a season with lots of snowpack and be fine, but how many season with little snowpack will you even survive?
60020. Steve Case at 14:05 PM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       Skywatcher, Thanks for the comment
60021. skywatcher at 14:01 PM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       #4 And if you read through the presentation slides themselves (noting that you are missing a vast amount of information as we are not hearing the presenter speak), you'll note a number of slides discussing why there's an apparent slowdown in the altimeter era. Chief among the culprits appears to be ENSO - the 1990s were dominated by El Nino, leading to higher apparent sea level, and the 2000s were dominated by La Nina, giving the reverse (histogram slide #15). There's an expectation that the apparent slowdown will reverse when El Nino conditions return. Hence the altimeter era is highlighting the variation of sea level around the obvious accelerating trend in sea level seen in Figs 1 & 2 above. The above graph is shown first at slide #9, discussions of possible reasons starts at slide #10, continuing to the summary at slide #23. Perhaps Steve Case could point us to where he thinks the presentation fundamentally contradicts our understanding of long-term sea level rise acceleration, as seen in Figs 1 & 2 above?
60022. Tom Dayton at 13:51 PM on 17 April 2012
       Newcomers, Start Here
       tmac57, tamino's got Spencer's latest slip covered at Open Mind.
60023. Steve Case at 12:49 PM on 17 April 2012
       Return to the Himalayas
       Daniel Bailey at 10:07 AM on 16 April, 2012

       How does the process of taking in snow in the accumulation zone, rain in the ablation zone and emitting water from the lower reaches vary all that much from melting snowpack and rain?

       I had said that this discussion would boil down to the difference between the melt rate of ice and snow.

60024. Steve Case at 12:39 PM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       If you go to
       aviso.oceanobs.com Mean Sea Level rise References

       You will find this link:

       Why has an acceleration of sea level rise not
       been observed during the altimeter era? R. Steven Nerem (University of Colorado)

       And this illustration on the last page of the presentation:
       http://i39.tinypic.com/nr14bq.jpg

       Moderator Response: TC: Link fixed.
60025. scaddenp at 11:37 AM on 17 April 2012
       Data Contradicts Connection Between Earth's Tilt and the Seasons
       Hi Manny. For a look at that predictive power, you might to look at this. The question is similar to how can you be sure that our experience of space-flight to the moon is enough to guide a space craft to pluto. The answer of course is that our confidence is based on understanding the basic physics. You should also be aware that modelling on one scale or another extends well past last century and seems adequate to explain most aspects of the evolution of climate through the history of the planet. For the evidence to support this, then please see the rather overwhelming detail found in the IPCC WG1 report. In the "Paleoclimate" (Chapter 6), you can see very much the graphs you are asking for. I would also strongly recommend you study this post from one of the modelling groups to understand what those model outputs mean.
60026. tmac57 at 10:27 AM on 17 April 2012
       Newcomers, Start Here
       Looks like Roy Spencer has 'slipped up' again: Virtually all of the USHCN warming since 1973 appears to be the result of adjustments NOAA has made to the data, mainly in the 1995-97 timeframe. Does this deserve a new post at SKS?
60027. skywatcher at 09:51 AM on 17 April 2012
       Return to the Himalayas
       wow - what a difference between the Guardian and BBC articles. You could use them as an educational example of how to place a story into context and how not to. Of course, one author is a science writer, the other a glaciology professor, and the difference in understanding is stark. Well done Prof Bamber!
60028. Tom Curtis at 09:43 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       Alexandre @19, having reviewed a large number of "home experiments" purportedly proving or disproving the greenhouse effect, my conclusion is that people conducting those experiments nearly always fail to control for other factors, and execute the experiment poorly. Even the Myth Buster's attempt may only show that the containers in the center catch more stray light from adjacent spotlights. What is more,the do not demonstrate the GHE, but only the fact that methane, and CO2 absorb IR radiation. This is more directly demonstrated by Iain Stewart for the BBC: A proper "home" demonstration of the GHE would require an investment of several hundreds of dollars for materials and instruments.
60029. noelfuller at 09:33 AM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       I observe that in most puddles the water spreads as the surface rises so even a linear rise or a small fall might still represent an accelerating increase in volume. "Sea level rise" is measurable of course which is why we use the term ,yet predictions and explanations of change in sea level are based on volume - volume of ice melting, measurable, volume of rain fallen as in floods, volume of ice still to melt, volume of water in the atmosphere as represented by percentage of water vapour. Discussion of Arctic Sea Ice Extent is a kind of analogue. It's readily measured but is highly dependent on how the winds are blowing. Do they push the floating chunks of ice together or drive them apart? But sea ice volume is quite another animal. As the ice thins it could increase in extent at times, depending on the winds. These differences between what is readily measured, ice extent or sea level, and what is really goin on, changes in volume, provides plenty of room for misunderstanding and misrepresentation. Noel
60030. Rob Honeycutt at 09:31 AM on 17 April 2012
       Return to the Himalayas
       muoncounter @ 19... The Guardian actually did a good job with this one. The glaciers are still shrinking – and rapidly
60031. Rob Honeycutt at 09:24 AM on 17 April 2012
       Return to the Himalayas
       Steve... I checked. Your comment was not deleted. But I do take exception to your "no comment" response at 16. An enhanced hydrological cycle means both more evaporation and more precipitation. Wetter and drier conditions.
60032. Tom Curtis at 09:21 AM on 17 April 2012
       Global Warming in a Nutshell
       davpaf @24, there is no reason why TS should equal TE, and unless you remove all greenhouse gasses it will not be. In removing all greenhouse gases, you need to remove not only well mixed GHG, but also water vapour and clouds. In the model runs by Lacis et al 2010, whose results I showed @22 above, TE is reduced by about 15 degrees C because the albedo in increased from 0.3 to about 0.42. That is compensated for by the remained greenhouse effect from water vapour and clouds so that by coincidence TS approximately equals the value of TE prior to the removal of CO2. Please note that in his comment @27, KR assumes zero greenhouse effect, which is a different thought experiment (see his comment @ 32). CBDunkerson @30, as already noted by KR, the model results I presented are for the removal of CO2 (strictly, all well mixed GHG so that it removes methane as well as CO2), not for the removal of all GHG including water vapour. Personally I am surprised at the results. It is known that the Earth entered a "snowball" state, with extensive continental ice at sea level at the equator, at least twice between 1 billion and 600 million years ago. The sun emitted about 10% less radiation then, which would make that easier, but the model results suggest that it is no longer possible for the Earth to enter a Snowball state, even with the complete removal of all CO2. A solution to the paradox may be that the model does not allow for the growth of ice sheets. That is, it only incorporates fast feedbacks. With the growth of ice sheets temperatures may fall further, flipping the Earth into a true snow ball state. Lacis et al also mention the simple ocean they use in the model as also potentially introducing a false stability to temperature. Regardless, I think we are in safe territory if we conclude that the removal of all well mixed GHG would reduce the Global Mean Surface Temperature by at least 30 degrees C, and probably significantly more if (as you say, magically) the Earth's atmosphere could be kept free of well mixed greenhouse gases.
60033. Manny at 09:18 AM on 17 April 2012
       Data Contradicts Connection Between Earth's Tilt and the Seasons
       Scadenp, I am male and you are criticizing me for the use of the word "proof". I recognize my error and will therefore ask for "evidence" that one century of hindcast is enough to support climate predictions for the next century. Skywatcher, I am not comparing apples to oranges, I am questioning the predictive power of the IPCC models. With your answer, you are implying that the modelers made no mistake and you are expecting me to trust you. Sorry, I do not. I want to see evidence. All I am asking is graphs of the output of the various IPCC models (there are several) vs observed temperature in order to judge the models for myself. Is this too much to ask?
60034. Minkie41 at 09:05 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       My own experience is that the well known Groucho Marx crack: "What do I care about posterity? What's posterity done for me? usually applies."I'll be long dead when it gets really bad" is a common response.Personally speaking,I'm a powerless-useless AGW flailer.Trying to pull up people's denialist anchors needs a Hercules because the AGW worry-load that is swopped for the anchor is groaningly heavy cargo.In any case,debunking denialism just creates more denialism feedback--more anchors.All I can offer is that we need to organise a la 350.Org and ACTIVATE! but just how:what's the best way? escapes me. Peter Cummins New Zealand
60035. LarryM at 08:53 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       I don't know if this is THE most difficult aspect of AGW to explain, but I think it's important. It's the difference between 'weather' and 'climate'. There are many tv weathermen out there who are climate deniers, and that's a BIG problem because 1) they have a tv audience of regular people, and 2) they have some science background and therefore some credibility to have a reliable opinion about climate change. They understand weather very well, but weather is more deterministic (meaning models that involve solution of a system of partial differential equations), whereas climate models are more statistical in nature and involve more sampling from probability distributions. We can't predict the weather much more than a week or so into the future, so how the hell can we be predicting it years or decades or centuries in the future? We need to do a better job of getting across to the general public (not just SkS readers) that climate is averaged weather, and it's an entirely different thing to predict and even to think about. And we need to start by educating the weatherpeople.
60036. LarryM at 08:02 AM on 17 April 2012
       Global Warming in a Nutshell
       @Chris G #17 and #25: I made a few changes to the caption of Fig. A4 to clarify that it is not just cloud particles but also re-emission of absorbed IR radiation that occurs at lower temperature levels and contributes to the lower effective temperature of the Earth's outgoing longwave radiation as seen from space. The excellent article suggested by @Tom Curtis #18, Greenhouse Effect Basics: Warm Earth, Cold Atmosphere, has also been linked. I also added a link to the excellent article mentioned by the moderator in comment #28, about energy flows in the Earth System, called Trenberth on Tracking Earth’s energy: A key to climate variability and change.
60037. Alexandre at 07:05 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       About the Issue of the Week: Debunking is a well-intended effort, but ineffective. It even reinforces those unfruitful "debates" with boneheaded "skeptics" - a waste of good minds. Explaining the science is good. How about some do-it-yourself experiments that the reader could try at home or at some simple lab? This would be much more effective than, say, 1000+ comments trying to explain to some hard-headed commenter why the 2nd law of thermodynamics is correct and consistent with the GHE. Much in agreement with ajki above.
60038. Same Ordinary Fool at 06:13 AM on 17 April 2012
       Which plants will survive droughts, climate change?
       It is truly sad that we really need to know about the importance of cell saltiness, and turgor loss points. Just in case we have to make the selections that Darwin thought natural. And then have to play Johnny Appleseed. But this is a good story about rigorous science. In which they had to solve, for the first time, the mathematical equations of wilting.
60039. lurgee at 05:26 AM on 17 April 2012
       Cliff Ollier: Swimming In A Sea of Misinformation
       'Ollier writes: "Note that the IPCC estimates have been falling with each report"' This is another meme that seems to be popular at the moment. Here in NZ, the obnoxious Matthew Hooton was grinding his teeth over this the other day (http://www.nbr.co.nz/article/sanity-prevail-climate-change-policy-115955). 'Falling predicitons' and 'Dying interest' seem to work quite well together, and both play to the publics general preference not to have to think that theior way of life is unsustainable,, destructive and making a horrible mess for their kids and grandkids.
60040. ajki at 04:58 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       Based on your personal experience, what is the most difficult aspect of manmade climate change to explain to the average person? From your perspective, has SkS adequately addressed this particular issue? I'm getting more and more pessimistic towards the effectiveness of the whole debunking process. One reason for this has lately publicly been brought up by Dr James Hansen (see Climate scientists are losing the public debate on global warming [Telegraph, UK]). Another reason for me is that the ongoing discourse has lost any rationally based angle (or never had that). When person A says "p!" and B responds with "non p, because...", you'd expect A to argue about the case and, eventually after a longish and intense discussion, A and B will come to an end (be it p, modified p, modified non-p or non-p). This whole concept of a discourse is plain and simple not existing regarding climate change. A very subjective perception is that for every great article on SkS or elsewhere 10 new blogs pop up with myth content that has been totally debunked 10, 15, 20 years ago. One reason for Joe Sixpack (or national equivalent) to "mistrust" the findings of the scientific community may be something like the notion 'This will cost me NOW!'. To counter that, SkS could possibly intensify argumenting within "It's not bad" or "Animals and plants can adapt" or the like. But SkS can't do that, since it can not and will not spread FUD. So beyond "Keep up the valuable work" I can't tell. Best, Andreas
60041. KR at 04:56 AM on 17 April 2012
       Global Warming in a Nutshell
       A side note to the last few comments: A simple thought experiment of removing GHG's shows an expected temperature of -18C. Tom Curtis linked to a model that included some secondary effects, such as albedo changes from ice growth and cloud cover, which reaches -20C even with some water vapor still present. But the core of the discussion remains, whether you attempt to account for all details of the extreme thought experiment - we're a lot warmer with greenhouse gases than we would be without...
60042. KR at 04:52 AM on 17 April 2012
       Global Warming in a Nutshell
       davpaf - "...the initial sentence of the paper is the basic assumption, which is unclear" Energy balance in the climate is determined by the difference between what comes in from the sun (240 W/m^2), and what gets radiated out to space (~239 W/m^2 or so at present, given the observed warming). Without GHG's, given the IR emissivity of the ground and water on the Earth's surface, 240 W/m^2 could be radiated with a surface temperature of about -18 C. That's as per the basic Stephan-Boltzmann equation. With the presence of various GHG's absorbing/emitting in the lower atmosphere, and the lapse rate of temperature fall with altitude, the top of troposphere location for those GHG's to effectively emit to space is both higher and colder than the surface - and since IR emission scales with T^4, they emit less energy than the surface or near-surface air could if directly exposed to space. This is often expressed as an "effective emissivity", or the proportion of a theoretic blackbody emission at surface temperatures. For our climate (as measured from space, relative to a 15 C blackbody) the effective emissivity is ~0.612, meaning that the Earth emits ~240 W/m^2 to space - rather than the ~396 W/m^2 emitted by the surface at that temperature. GHG's slow the effective cooling to space - and hence a higher temperature on the surface is required (higher than required without GHG's) to match incoming energy with outgoing IR.
60043. KR at 04:36 AM on 17 April 2012
       Global Warming in a Nutshell
       CBDunkerson, davpaf - My apologies, I was thinking of the more extreme thought experiment with no greenhouse gases, not just missing CO2 (and methane). However, the link Tom Curtis gave above looks to be a model of just that situation, removal of non-condensing GHG's - a cooling Earth, condensation of water vapor reducing the absolute humidity, tapering off to a temperature of about -20 C.
60044. John Hartz at 04:16 AM on 17 April 2012
       Polar bear numbers are increasing
       The denier meme identified in the OP is a quote of Mitch Taylor who was billed as a “leading Canadian authority on polar bears.” Thanks to Peter Gleick, we now know that Mitch Taylor receives a monthly stipend from the arch-conservative US think-tank, The Hearltand Institute. For more details about the Taylor-Heartland connection, check out: “What passes for a Brain Trust at Heartland?” by Richard Littlemore, DeSmog Blog, Feb 24, 2012
60045. John Hartz at 03:55 AM on 17 April 2012
       Polar bear numbers are increasing
       Seems to me that the OP should be updated to reflect the scientific findings that have been published since Sep 2010.
60046. John Hartz at 03:52 AM on 17 April 2012
       Polar bear numbers are increasing
       Speaking of polar bears, here are a couple of interesting facts about where they came from and where they may be headed. “Polar bears have maternal Irish brown bear ancestors” by Stephen McKenzie, BBC News, Jul 7, 2011 “Brown and polar bears set to mate again due to global warming” by Cathy Hayes, Irish Central, Jul 13, 2011
60047. davpaf at 03:42 AM on 17 April 2012
       Global Warming in a Nutshell
       I am not in any way in doubt about the radiative characteristics of the different gases! Here what I understand so far: As you have pointed out in the figure of this article, various gases have different characteristics of emitting radiation. According to the figure the major players seems to be Water vapour & CO2. So if in our thought experiment an atmosphere without CO2 is present, there are still gasses available which will provide radiation to space, hence the atmosphere will be radiating to space. So the two components from before, atmosphere + surface, both radiating are still present, leaving me with my original question why it is valid to disregard the atmospheres part. Thanks for the link to the paper admin. As I understand it is mostly on the effectiveness of the individual greenhouse gases, and how individual and combined effects are important. But still the initial sentence of the paper is the basic assumption, which is unclear: “The global mean greenhouse effect can be defined as the difference between the planetary blackbody emitting temperature (in balance with the absorbed solar irradiance) and the global mean surface temperature. The actual mean surface temperature is larger (by around 33°C, assuming a constant planetary albedo) due to the absorption and emission of long‐wave (LW) radiation in the atmosphere by a number of different “greenhouse” substances.” I have also checked the reference of this quote in this paper (Charney, J. (1979), Carbon Dioxide and Climate: A Scientific Assessment,Natl. Acad. Press, Washington, D. C.) but don´t seem to find its origin.
60048. CBDunkerson at 03:40 AM on 17 April 2012
       Global Warming in a Nutshell
       Tom & KR, note that the original hypothetical was just the removal of all carbon dioxide from the atmosphere... not all greenhouse gases. Of course, it would be impossible to remove all CO2 without also removing all methane (which breaks down into CO2)... and the temperature drop from decreased CO2 would perforce cause a significant reduction in atmospheric H2O... However, I ignored all of that in my response... which was then still just a wild guess. The ~33/34 C values you are citing would be removal of the entire greenhouse effect... though I believe even then it isn't accounting for additional cooling which would result from the albedo shift. Basically, it is a physically impossible hypothetical and thus the answer depends in large part on what assumptions we make to 'gloss over' the inherent contradiction of CO2 levels somehow changing to zero independently of all interconnected factors. It would be cold exactly how cold is impossible to say without understanding the magical process which allows the atmospheric CO2 to drop to zero.
60049. vrooomie at 03:29 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       chriskoz@3: You ask: "What is the difference between "denier" and "denialist"? And similarly, between "denial" and "denialism"?" As a paid skeptic (geologist) here's how I define it: Deniers/denialism reject *any* evidence of AGW/CC regardless of its robustness or irrespective of how well vetted the data is. To utilize an oft-used term, they are the 'birthers' of the science world. skeptics, OTOH, question the data and interpretations of data NOT with ad hominem attacks, or hyperpartisanship: they act as any good scientist should, by analyzing the extant evidence then addressing that with science-based rationale.
60050. vrooomie at 03:24 AM on 17 April 2012
       2012 SkS Weekly Digest #15
       lurgee@1: As a earth systems scientist who battles this type of disinformation almost daily, the best I can offer as an answer is: -Rampant Dunning-Kruger, coupled with; -wishful thinking, that if the deniers say it loud enough and long enough, the general public will believe it. given their overwhelming success at that tactic so far, I wouldn't count them out. I will, however, continue to add my voice to the side of reasoned, rational and non-hyperpartisan science.

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