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mspelto at 05:41 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
#30 and #32 whether you look at the Alps, Sweden, North Cascades etc. there were significant advances in the 1950-1980 period. The glaciers have since entered a very pronounced and significant retreat that has led to the loss of a number of glaciers. This is not merely an ongoing retreat since the Little Ice Age note three of hundreds of examples that could be givenMer de Glace or Brady Glacier orGigjokull before the eruption. True there are many that have been retreat ever since the LIA, but it is not the majority in most alpine ranges. -
Kiwiiano at 05:14 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
And don't forget that the need for mass evacuations and the loss of many ancient and treasured cities & their infrastructure will be against a background of rapidly depleting resources and the end of cheap energy. -
aj1983 at 04:28 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
@Alexandre: Yeah, but not if you are living near or below sea level in the Netherlands (or several other places), then every meter becomes very much inconvenient. Our species is not very much at risk, but our modern society is much more vulnerable. BTW, at many places glaciers have been melting since the little ice age, I think you can find many examples in the NH. However, the rate of melting seems to be accelerating, which is a bit worrying. How large the impact of natural variability is compared to AGW we will probably see in the next few decades, because of the quiet sun and negative PDO (which have both been proposed by the skeptics for giving large global temperature variations). -
A visual depiction of how much ice Greenland is losing
gallopingcamel @#25 and nofreewind @#3, Even if there was glacier retreat in 1900, it would be consistent with the steady increase in global temperatures at that time. CO2 does not cause glaciers to retreat, CO2 causes warming which causes glaciers to retreat. Unlike the warming that began around 1970, the warming from about 1850 to 1940 was primarily due to an increase in solar activity. This is discussed some here. It is also worth pointing out that the warming now is already more extreme than the 1850 warming period, and projected to get worse. To the other question, even if temperatures were stabilized today glacier retreat would continue for a long while, there is nothing inconsistent about this. This was already pointed out in John's original post: "It takes time for the massive Greenland ice sheet to respond to warming." The glacier retreat you see today is the result of warming in years past. Unfortunately temperatures are continuing to rise, so not only will the melting continue, it will get worse. -
Rob Honeycutt at 03:11 AM on 28 April 2010Has Arctic sea ice returned to normal?
@CBDunkerson... Thanks for that response. I guess I'm also curious about the relative importance of summer and winter extent. Winter ice extent is, I'm assuming, a nominal feedback and mostly an annual data point, whereas summer ice is going to be a more important data point because it's going to suggest more about ice volume and positive feedback due to the albedo of the open ocean. -
Rob Honeycutt at 02:54 AM on 28 April 2010Has Arctic sea ice returned to normal?
@nofreewind... I'm not sure you can call two positive upticks a recovery in the face of 30 years of negative trend. If that positive trend continued for the next 5 years we might have something to begin talk about. But I don't think this answers my question. I'm actually asking less about the disingenuousness of WUWT and more about the lack of negative feedback because winter ice extent occurs mostly during the 24 hr darkness of winter. I'm not suggesting that the winter ice extent isn't important - it's a relevant data point - but with regards to climate change winter ice extent is going to offer very little of what one might hope for: Increased albedo and some negative feedback. (FWIW - We should ALL be hoping that there are more negative feedbacks out there than science seems to be currently finding.) -
Alexandre at 02:48 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
It´s only a small fraction of Greenland´s ice each year. It´s only a tiny increase in CO2 concentration each year. And hey, a few meters of sea level rise are pretty insignificant compared to the total ocean depth. Rationalization is the ultimate solution to global warming. -
Riccardo at 02:29 AM on 28 April 2010Tracking the energy from global warming
Just one more tiny bit of informations. A huge current originating in Antarctica and flowing northward in the Indian Ocean below 3000 meters has recently been discovered. It's volume transport is around 30 Sv. For those of you not familiar with this unit of measure (Sverdrup), 30 Sv are about 20% of the maximum transport of the Gulf Stream (which so nicely helps warming north-western Europe :)). There's much more in the deep ocean than we'd like to admit.Response: Thanks for the link to the Nature article, that's a fascinating development. Considering the Southern Ocean is warming faster than the global trend, I wonder if this is a possible mechanism for transporting extra heat to the deep ocean. I noticed a comment posted repeating the common error of confusing sea ice with land ice and posted a follow-up comment.
So one Sverdrup is equivalent to 30 million cubic metres per second. Hmm, I wonder how big that much water would compare to the Empire State Building... -
Chris G at 02:08 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
#16 Arkadiusz, "By this work in the years circa 193X-5X in Greenland was warmer than today " I understood the work to say that the slope of the 'line' (line segment?) was steeper then than more recently. That doesn't say anything about the height of the line, and temperature is X. Regarding #3 NoFreeWind, #8 rway024, #22 CBDunkerson #23 The Ville, #25 gallopingcamel, @#25, It's hard to know how to answer questions that imply what you believe to be a false premise. (Have you stopped beating your wife?) If you are going to answer at all, the first step has to be pointing out that the premise is false. Once the premise has been shown to be false, there's really no need to answer the original question. (#3, #8, #25) @#23, "Prior to about 1999 Greenland's ice sheet was pretty much in mass balance." (#22) is at least in part a response to "Greenland has been warming and loosing ice for well over 150 years" (#3) @#8, 'glaciologist not a "glacierologist" ' is a bit of a nit-pick. You're correct of course, but Camel is right, there's no need to make a point of it. Lastly, and to further address one point from #3, "Temperatures didn't seem to rise but glaciers did melt." It might be useful to remember that, in proximity of a phase state change, temperature looses its tight coupling with energy. The temperature in a glass of ice water will not change significantly between when it is mostly ice to when it is mostly water, but there is a lot of energy change. But then also, melting isn't the only way for a glacier to retreat. -
chris at 01:39 AM on 28 April 2010Tracking the energy from global warming
Ken Lambert at 00:15 AM on 28 April, 2010 That's not really right Ken. As kdkd says, measurement errors over very short periods of observations/data collection can easily confound interpretations. One needs to be confident of the measurements before making significant interpretations. That's a basic tenet of science. There's not much point in running free with calculations and various forms of numerology, unless one is fairly certain of the data; without that your interpretations are really only "theories" or hypotheses". That confidence (that the data is a true measure of the phenomenon under investigation) comes from (a) analysis of trends over sufficiently long periods that measurement and stochastic variations average to small values, and (b) having sets of self-consistent independent data (e.g. sea level rise and its mass and steric contributions; ocean heat measures; radiative imbalance etc.). So for example although the rate of sea level rise was apparently a bit slower for a couple of years, it's still smack on the 3.2 mm line now (see updated data in my post above), and there isn't really any evidence that the rate of sea level rise has slowed down. Your comments about solar and greenhouse forcings aren't quite correct. Remember that one can only interconvert forcings and temperature changes under equilibrium conditions. Otherwise one needs to factor in the various response times of the climate system. So the expectation that the effect of the solar cycle downturn on surface temperature on average temporarily (5/6 years) cancels the temperature rise from the enhanced greenhouse forcing doesn't say anything necessarily about the relative magnitudes of the forcings (solar and enhanced greenhouse). It just means that surface temperatures are rising near 0.15-0.2 oC per decade under the cumulative greenhouse forcing, and that the solar cycle opposes this by around 0.1 oC during the 5/6 years of the solar downturn and supplements this ( by a similar amount on average) during the 5/6 years of the solar upswing. -
Cecilia at 01:11 AM on 28 April 2010Phil Jones says no global warming since 1995
Could I ask what the significance level (confidence level) of 1995-2009 really is? I've read blogs about 92-94%, but is this correct? -
CBDunkerson at 01:04 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
Ville, your general conclusions are valid but there are a few caveats. First, the 'doubling every six years' scenario is extremely unlikely and the only one which would require immediate action. For any other plausible situation we've got some time to work with and thus can afford (on this issue) to give it several more years to see how the trend line is actually developing. Currently we don't know if it going to be decades, centuries, or millennia... in ten years we likely will (though still not exactly how many). Each of those timeframes requires different kinds of planning. Thus, yes we should be planning for long term sea level rise. However, I think we have time to see how that is going to develop to better inform our efforts to handle it. Of course, all of this is just Greenland. Antarctica is melting too... and oceans are also rising from thermal expansion. However, even with all those factors combined we have time to see how trends are going to develop before taking action. -
mspelto at 01:03 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
I like the graphic. I would like it better if the cubes had more of glacier blue and a bit glacier textured. Then again I think glaciers are gorgeous. Two points to note, going back to a conference I attended in 1985 that was looking at the future of Fast Glacier Flow, we presented work on why the Jakboshavns would speed up in a warmer climate and why other glaciers could become more like the Jakobshavn. It turns out the mechanics behind this forecast were essentially correct. It is the number of Greenland glaciers that are responding that is most striking. All of the 34 largest marine terminating outlet glaciers have accelerated, even the thinner, slower, northern outlet glaciers Humboldt and Petermann Glacier are. -
LordLiverpool at 00:32 AM on 28 April 2010Climate's changed before
The mistake on the part of environmentalists has been to talk about "saving the planet". This leads directly to the sceptics' argument that the planet has changed in the past, and done just fine. Quite true. But we're not really interested in the planet, we're interested in our own welfare. A dramatic change in the climate would, first and foremost, affect our civilisation. Our cities, farmland and economies are far more vulnerable than the planet itself, which will no doubt continue to adapt. To win the global warming argument politically, we need to underline the threat to ourselves from climate change, rather than talking about ice sheets, polar bears and barrier reefs (important as those things might be). -
kdkd at 00:25 AM on 28 April 2010Tracking the energy from global warming
Ken, From a big picture perspective, the "missing heat" of the last 5 or 6 years is most likely caused by measurement error in a large complex stochastic system. I previously showed you that the OHC/TOA trends were statistically indistinguishable from the Temperature Anomaly / CO2 level trends over similar time scales / number of data points. At the level we're analysing it here, as armchair scientists, this point is extremely important, as it clearly shows the limitations of the conclusions which we can draw from a fairly superficial examination of the data. In turn, this strongly suggests that your argument is based around confusing uncertainty in the measurement systems with flaws in theoretical understanding (thanks Chris!). Unless you can demonstrate some large, statistically robust support for your argument, it's an interesting footnote on how not to draw conclusions from statistical noise. A 30% error term is quite reasonable for systems of this complexity. In the social sciences where I come from, we deal with these kinds of error magnitudes all the time. -
Ken Lambert at 00:15 AM on 28 April 2010Tracking the energy from global warming
Chris #76 We are all waiting for BP to respond to Posts #73 thru #76. Meanwhile your points ignore the 'missing heat' divergence over the last 5-6 years as exampled at the start of this discussion. BP's argument is that the OHC for the top 700m of ocean is a direct measure of the integrated TOA forcing imbalance WRT time because there are no other serious heat storages in the system other than the oceans. So far, only von Schukmann has found 'missing heat' down to 2000m - but we lack a convincing theory of a mechanism to get it there. It should be noted that sea level rise over the last 5-6 years on your above chart has flattened to a slope of 1-2mm/year consistent with flattening temperatures. The 11 year solar cycle varies the solar forcing by at most about 0.25 W/sq.m - when Dr Trenberth postulates a TOA imbalance of 0.9 W/sq.m due to CO2GHG and other heating and cooling effects. If you are claiming that a solar drop of 0.25W/sq.m or less has flattened the temperatures, and if the other heating and cooling effects (aerosols etc) forcings remain the same then the CO2GHG effects must be efectively negated by a 0.25W/sq.m drop in solar, which implies that they are nearer to 0.25W/sq.m than 0.9W/sq.m imbalance (mainly based on a CO2 component of about 1.6W/sq.m) Again the 'missing forcing' would be about 0.65W/sq.m. -
gallopingcamel at 00:09 AM on 28 April 2010A visual depiction of how much ice Greenland is losing
rway024 (#8), "nofreewind" (#3) posed some interesting questions that you failed to address. Instead you attacked his credibility which makes no sense when he was merely asking questions. Why don't you have another go at answering "nofreewind" and this time stick to the point and lay off the "ad hominem" stuff. -
Jim Eager at 23:51 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Re JRuss@4, those rumors of active sea bed volcanoes adding tremendous heat to the arctic ocean fail to consider the need to warm the entire water column between the sea bed and the surface before there would be any heat gain at the surface to melt any ice. In other words, they are not just rumors, they are complete nonsense. -
Paul D at 22:55 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Re CBDunkerson and comment no. 22 Some points: 1. Does it matter when the ice sheet has melted? The eventual result is the same. Coastal cities will be flooded and problems for human populations will occur. 2. 3 out of the 4 scenarios you portray are very serious. Lets take the Linear example first. It is generally accepted that the greenland ice sheet will add some 6m or so to sea levels. So in 450 years time a large number of coastal cities will be under water. Ok, 450 years is apparently a long time. But the real problems will still plague coastal cities and communities long before then. Add just 2 or 3 metres in 200 years or so and many coastal city communities will have serious flooding problems. In any case the ultimate fate of many cities will be mass abandonment and migration inland, it doesn't matter when that will happen, the fact that it will happen is the problem. 3. The non-linear scenario doesn't really need explaining once the consequences of the Linear scenario is clarified. Cities would probably start planning for mass evacuation now. 4. If the actual scenario is somewhere between linear and non-linear, then we still have some very serious problems. Evacuation probably needs to be planned for the next century or towards the end of this century. So given that in all probability flooding will occur, risk analysis suggests we should do something about it. -
chris at 22:23 PM on 27 April 2010Tracking the energy from global warming
whoops....I should have said: "Yes the radiative forcing contribution from [CO2] has gone up a tad since 2003" -
chris at 22:04 PM on 27 April 2010Tracking the energy from global warming
Berényi Péter at 13:01 PM on 24 April, 2010 lots of problems with your argument Peter. 1. "We have a negative energy balance for the last six years. The climate system is not gaining energy, but losing it." That's almost certainly incorrect. Since sea levels are continuing to rise (see below), it's almost certain that the climate system continues to gain energy. You're making the logical error of equating uncertainty in measurement systems as an indication of a flaw in theoretical understanding. As always, we need to resolve the uncertainties in measurements before making interpretations about phenomena and our understanding of these. 2. "But wait, CO2 has increased from 375 ppmv to 389 ppmv between 2003 & 2010. The change in radiative forcing during this period is about 5% of a CO2 doubling." Yes the change in radiative forcing has gone up a tad since 2003. And global temperatures have risen through at least 2005 (e.g. here or here). Since around 2002 the solar output has descended through the decreasing part of the solar cycle to an abnormally extended minimum. Under normal circumstances we expect the downward part of the solar cycle to give around 0.1 oC cooling contribution to surface temperature (lagged by a few months). In other words it should temporally counter all the surface warming from CO2-induced greenhouse forcing during this period. We might expect a slightly larger effect of the proesent extended solar minimum. So there's nothing surprising about the fact that surface temperatures haven't risen very much since 2002/3.
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CBDunkerson at 22:01 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
The Greenland ice sheet covers about 2.85 million cubic kilometers and one cubic kilometer of ice weighs about 0.9 gigatonnes... so we are looking at a total of around 2.57 million gigatonnes. Prior to about 1999 Greenland's ice sheet was pretty much in mass balance. It had dipped slightly and then rebounded in the 70s, but otherwise nothing but minor fluctuations for decades. Since 1999 it has dropped at a precipitous and accelerating rate. If we assume that this acceleration stops and Greenland will continue losing ice at 286 gigatonnes per year then it would take about 9,000 years for the entire ice sheet to melt (which matches Berenyi's 15 g out of 150 kg = 10,000 years pretty well). If we instead assume that ice loss will continue to increase at a LINEAR rate equal to what it has been recently (a little under 25 gigatonnes per year) then it would take about 450 years. Finally, if we assume that the rate continues to double every six years then it would take about 60 years. We probably need AT LEAST a decade more data to get any kind of handle on what sort of long term trend we are likely to see, but if ice loss is being driven by CO2 caused warming then the answer will likely be somewhere between the last two figures... though since we are looking at such a small time frame, slightly increased CO2 levels over that period would have a negligible impact, and we are really talking about the melt rate at the CURRENT CO2 level. If CO2 continues to increase the melt time would decrease. -
kdkd at 21:51 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
The butterfly effect is a casual expression referring to to something called "sensitivity to initial conditions". The outcome of the energy calculations will still require that the energy is spent somewhere, be it on change in ice conditions, temperature changes or whatever. In fact, that the (old) models predict precocious arctic warming, and relatively little tropical warming is an example of this sensitivity dependent on initial conditions that you refer to. However it's not a "get out of jail free card" for not needing to understand how energy calcualtions and statistical probabilities work, it's rather more subtle than that. -
Riccardo at 21:32 PM on 27 April 2010CO2 effect is saturated
qball17, Miskolczi's "paper" is well known and badly flawed. As Eli at Rabett Run ironically puts it, his theory could be summarized in just two sentences: "The greenhouse gas theory that has been used for the last century is TOTALLY WRONG! The proof is left as an exercise for the reader.". -
Arkadiusz Semczyszak at 21:31 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
"I's very unlikely" - This is very vague in the context of chaos theory, "butterfly wings" ... 9% or 80-90% - "the same end result" ? It,s only "weather" ? -
kdkd at 21:19 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Arkadiusz #18 I'm not sure of the purpose of repeating what I said back. My point was that the weather that causes the melt is at least somewhat independent of the climate (e.g. manifested by temperature anomaly. Modeling the temperature and the climate are essintially independent tasks. I's very unlikely that a model of the weather will be able to falsify a model of the climate. -
Arkadiusz Semczyszak at 21:11 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
"... but you'd have to develop an understanding of what the RELEVANT parameters were." - exactly yes ... -
CBDunkerson at 20:59 PM on 27 April 2010Has Arctic sea ice returned to normal?
Berenyi, as noted previously in comment #50... the ICESat satellite provided Arctic ice volume measurements which closely matched the PIOMAS model. ICESat is no longer functioning, but the Cryosat II satellite launched several weeks ago will be able to provide the same sort of data in a few months. Thus, this September we will be able to compare PIOMAS not just to the measured sea ice extent, but also the actual measured volume. If it continues to match up to then it would seem to be a fairly solid model. In any case, the fact is that we DO have direct ice volume measurements and they will tell us whether it is 'recovering' or not. robhon, in addition to albedo not being much of an issue during the arctic Winter it needs to be understood that sea ice extent is not DIRECTLY determinative of albedo. Sea ice area, the total surface area of ice floating in the ocean, determines albedo. This differs from extent in that extent is not the area of the ice itself, but rather the area of the ocean which is at least 15% covered with ice. So the extent can be as much as 1 / 0.15 = 667% as great as the ice area. This means that minor fluctuations in extent may or may not tell us anything about albedo... the extent could have changed because the area of the ice did OR because the ice was more or less spread out. This is one of the reasons why extent is really only useful for determining long term trends and making statements about 'recovery' based on minor variations in a couple of years are not just 'disingenuous' but clearly unfounded. -
kdkd at 20:47 PM on 27 April 2010CO2 effect is saturated
qball17 #13 That's not a proper scientific paper, it's a paper from the partisan Science and Public Policy Institute (home of among others the rather badly discredited "Lord" Christopher Monkton, and the australian geologist Bob Carter). If there was any merit in the presentation/summary that you printed, then it would be easy for him to publish in a reputable scientific journal. So you have to ask the question why hasn't he? The papers cited at the top of this page are a much better source for you to form your opinions from. -
kdkd at 20:34 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Arkadiusz #16 There's an old saying in the field of computational neuroscience: "The implementation is independent of the architecture". That is, there are many different paths to the same end result. As far as Arctic ice loss goes, predictions from fairly old models (I have a text book about 20 years old that presents a model predicting ice loss specifically from AGW) state that ice loss is hypothesised to occur due to warming caused by CO2. The model has nothing to say about the mechanism by which this occurs - it could be by the ice being pushed around differently by changes in weather/win patterns, or it could be by it sitting there melting. The models don't care, they just predict the outcome, not the mechanism. So the changes in wind patterns are not any sort of evidence for or against the anthropogenic cause of Arctic ice loss. You could of course try to develop a model looking at what different mechanisms of arctic ice loss may occur under different global warming scenarios, but you'd have to develop an understanding of what the relevant parameters were. -
qball17 at 20:17 PM on 27 April 2010CO2 effect is saturated
hey guys, i think you should all look at Dr. Ferenc Miskolczi's theory on the saturated effect of greenhouse gases. you can download his paper for free on scribd. http://www.scribd.com/doc/25071132/The-Saturated-Greenhouse-Effect-Theory-of-Ferenc-Miskolczi . i would love it if you guys have a look at it and get back to me.. because it looks very very convincing.. so if someone can have a look at the math involved and see if its all legit that would be excellent.. here is the link to the summary report of his findings aswell; http://www.scribd.com/doc/25071473/Saturated-Greenhouse-Effect-Theory He says that the climate models used by the ipcc are based on old math from the 1920's which make an assumption that the atmosphere is infinitly large.. he redoes the math with proper boundary conditions and comes up with very interesting results.. i'll leave it up to you guys to look further into it email me on coatesy91@hotmail.com if you'd like to send me your thoughts if youd prefer that than this comment cheers -
Arkadiusz Semczyszak at 20:02 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
"The decline in the Arctic sea ice from 2005 to 2007 was caused by winds, according to a NASA study . Atmospheric pressure conditions set up wind patterns that compressed the old thick sea ice, loaded it into the Transpolar Drift Stream and then increased its flow rate out of the Arctic along East Greenland. By this the perennial thick sea ice in March 2007 essentially was confined by winds to the Arctic Ocean north of Canada. Consequently, most of the Arctic Ocean was dominated by thinner seasonal ice than usual, melting faster. In addition, this thin ice is more easily compressed and responds more quickly to being pushed out of the Arctic by winds. This thinner seasonal ice conditions facilitated ice loss, leading to the 2007 record low amount of total Arctic sea ice." "Oceanic control of the warming processes in the Arctic - a different point of view for the reasons of changes in the Arctic climate" - professor A. Marsz, 2009. Summary "The paper describes the strong correlation between the sea surface temperature (SST) in the region of the Gulf Stream delta and anomalies in surface air temperature (SAT) in the Arctic over the period 1880-2007. This correlation results from the transfer of a variable amount of heat from the Atlantic tropics into the Arctic through oceanic circulation (AMO - Atlantic Multidecadal Oscillation). Reaction of sea ice is the main mechanism controlling the heat content in water carried to the Arctic and influencing the SAT. Sea ice may either increase or limit the heat flow from the ocean to the atmosphere. The genesis of the 'Great warming of the Arctic' in the 1930s and '40s is the same as that of the present day. Both may be considered to be attributable to natural processes and are not demonstrably associated in any way with a supposed 'Global greenhouse effect'. CHANGES IN THE CONCENTRATION OF CO2 IN THE ATMOSPHERE COULD ONLY EXPLAIN 9% [!] OF VARIATIONS IN THE SAT IN THE ARCTIC." "Greenland Ice Sheet Surface Air Temperature Variability: 1840–2007*" Box et. al. 2009, AMS - "The annual whole ice sheet 1919–32 warming trend is 33% greater in magnitude than the 1994–2007 warming." (http://www.worldclimatereport.com/wp-images/greenland_xmas_fig1.JPG). By this work in the years circa 193X-5X in Greenland was warmer than today ... -
Berényi Péter at 19:49 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Speaking of visual depictions...
Imagine a fat man, weight 150 kg (330 lbs) losing 15 g (half an ounce) a year. This is the type of slimming cure Greenland is going through recently.
Response: LOL, can I ask what value you used for the total ice mass of the Greenland ice sheet and your source?
Of course, when I look at that picture, it reminds me of the numerous papers that have looked at the last interglacial when temperatures were 1 to 2 degrees warmer than now (eg - the warming expected from some of the more optimistic emission scenarios). They found that sea levels were at least 6 metres higher than current levels. Looking at all the ice still stored in Greenland, it's not hard to see why. Going on past history, Greenland (and Antarctica) are very sensitive to sustained warmer temperatures. -
sailrick at 18:38 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
It seems to me that talk about whether the MWP was as warm as tody, has little relevance to today's situation, which is one in which it is the future that is of concern, with possible runaway global warming, caused by man releasing into the atmosphere, within a few hundred years, the carbon that nature has been sequestering in the form of coal for 65 million years. That has never happened before. We know CO2 is a greenhouse gas and how much we are emitting. The greenhouse effect has been known for over 150 years. We know that on our current path, CO2 concentrations could triple from pre industrial levels in this century. If you knew nothing else about climate change or maybe had never heard of it, or the politics of it, and you learned the above, what would your initial reaction be? I would think common sense would give you concern. So why are so many intent on denying it? -
barry1487 at 17:57 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
'Human industry' did not double? There's no reason why regional ice loss rate should match the vector on global CO2 emissions. The dynamics in play are completely different. What they have in common is increased warming. I would caveat the top post by mentioning that 7 years of data is a little short to make confident analyses of trends. -
RSVP at 16:55 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
There is a clear doubling rate associated with the two blocks for 2002 and 2009, yet human industry did not double during that same time frame. This could lead one to conclude that the melting does not correlate with human activity, and furthermore, even if it did, changing human behaviors will not stop it. It would be interesting to see a similar ice cube representation for a much earlier year, and as HumanityRules commented, how this matches up with the entire Greenland icesheet. -
Geo77 at 16:51 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
John- If I were in the audience my first question would be how long would it take to lose half of the Greenland ice sheet to melting at a rate of appx. 300 gigatonnes per year? Also, Humanity Rules comment should give you forewarning to be prepared for questions about the MWP and early Norse settlements. If there is more or almost equal ice volume in that area of Greenland today when compared to the Norse settlement period you're going to lose some of your audience regardless of the science. -
HumanityRules at 16:32 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
The Climatic Research Unit made a merged SW Greenland temperature record which showed the 1940's were as warm as the present period. (It's contained in the PDF linked at the top of their page) Many of the same group have recently produced a paleoclimate reconstruction of Greenland temperature going back 1400 years showing a MWP as warm as present day. Greenlands temperature has shown a fair amount of natural variation no doubt allowing periods of retreat and advance over the past 1400 years. The real skill is putting the changes of the past decade into a context that fully aknowledges this natural variation. Terms such as "steadily accelerating ice loss" are meaningless without putting a timeframe on them. -
Philippe Chantreau at 16:26 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
About sea ice area, The graphs of sea ice area anomaly at Cryosphere Today do not support the assertion that Arctic Sea ice has increased. The Tale of the Tape shows that it has not experienced a meaningful positive anomaly since 2003, even with the new baseline including all years until 2008. The global sea ice shows negative anomaly at or greater than 2 million sq.km for the past 4 years. The last positive anomaly of similar magnitude was in 1988 -
robert way at 14:28 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
nofreewind, First of all, its a glaciologist not a "glacierologist" as an individual who studies "glacierology" (as you would put it instead of Glaciology) I can assure you that your credibility was lost with that one sentence. Secondly, Greenland has not been melting for 150 years. See Wake et al. 2009 for confirmation of this. There have been many periods of growth over the last 150 years. Thirdly, Glaciers still retreat with increased precipitation because they are dependent mostly upon Summer Air Temperature even more than Winter Precipitation. Ablation occurs faster than accumulation. Fourthly, The rate of sea level rise is currently at 3.4 mm per year (Cazenave et al. 2008) whereas the TAR (IPCC Third Assessment Report) predicted rates of 1.9 mm per year. That's an 80% acceleration over the expected results... So I don't see how you indicate that the rate of sea level rise is not accelerating? -
James Frank at 14:25 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
The visual is interesting. In terms of illustrating the size, you lose something by stacking the cubes into a larger cube. There is far more volume there than one sees at first glance. Something like a bar graph (2 dimensional instead of 3, even though we're measuring volume) would help avoid that. Or, as someone already pointed out, a comparison image of the ice in the sheet. If that was too large to work, perhaps the ice added in the same years? -
scaddenp at 14:19 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
JRuss - Antartica needs more precipitation on the cap than it loses in calving. Check the papers on ice loss. antarctica gaining ice Arctic sea ice grew from 2004 to 2009? Would take some special cherry-picking to support that, like the cherry-picked range for temperature. Try the long term data - eg Graphs in Has-Arctic-sea-ice-returned-to-normal And the old "volcanoes under the ice" trick. This is disinformation. Dont fall for it. Some discussion at dotearth -
robert way at 14:15 PM on 27 April 2010Has Arctic sea ice returned to normal?
I actually commented over at Watts Blog about how it was disingenuous for him to insinuate that volume was increasing at the end of his blog post and I got a couple snippy comments back but no refutation. -
brjohn9 at 14:08 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
JRuss, it's misleading to talk about a "decline in Global temperature from 2004 to 2009," not least because NASA puts 2005 as the warmest year on record. It puts 2009 as tied for second warmest. The real point is that fractions of a degree off the all-time record do not constitute a meaningful "decline" in temperatures. Even if that statement was true, Arctic sea ice has increased marginally in surface area since its all-time low in 2007, but it remains far belows its average extent in decades previous. Moreover, while the surface area has recovered somewhat, there is strong evidence that much of the new ice is so-called rotten ice that will melt again easily, rather than the multi-year ice that is resistant to melting. Also, the Arctic sea ice minimum is driven by factors much more complex than the global average temperature. Finally, why are you repeating crazy "rumors" you "heard" about active volcanoes melting Arctic sea ice? Let's stick to actual science, shall we? -
JRuss at 13:34 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
My handbook of Chemistry & Physics [1962]says the density of ice is 0.917. Taken to the minus one-third power, that would be 1.0293 km on a side for Gt cube. [Yes, that assumes the ice is pure H2O and is without voids.] I heard the other night that Antarctica ended its 2010 'Summer' at minus 100 degrees Fahrenheit. So perhaps the Antarctic can now gain back some ice. Because of the decline in Global Temperature from 2004 to 2009, the arctic ice has grown in area. The rumors I have heard is that there are three active volcanoes in the arctic ocean that are adding tremendous heat to the arctic ocean and that prevents a gain in the thickness of the thin ice covering the arctic ocean. -
nofreewind at 12:41 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
Ok, Greenland has been warming and loosing ice for well over 150 years and surely that guy above has some pretty cool photography. I was able to catch his show on cable and the pictures were beautiful on my TV. Call me a skeptic, but I don't completely "trust" that this ice loss necessarily correlates with the big TV that I watched the James Balog show on. We know man has pumped tons of CO2 into the atmosphere and the amount has risen exponentially since the mid 1850's. But why were many of the worlds glaciers retreating at a good pace in 1900 when we emitted only 1/8th of the CO2 that we are now? Why were the glaciers in Greenland retreating throughout much of this century when the Greenland temperatures were stable? The same thing was evidenced by the paper written by the glacierologist from India. If man has been only responsible for temperature rise from 1975 onward, why were glaciers melting since 1850? Why are glaciers retreating if the world precipitation is supposed to be increasing because of the super computer climate models, just like the heavy snowfall this winter in the NH was all expected and "modeled" apparently, (but i'm not so sure about that, because there were many IPCC references of less snowfall, but I guess the theories seemed to just change this year in light of the new data. I did the same things as this did here in Montana at Glacier NP and came up with the same results using the raw data from NOAA. Temperatures didn't seem to rise but glaciers did melt. Call me a skeptic, but I am not so sure we have anything to worry about. Surely world sea levels are rising, but isn't this about the same rate as it was when man was just getting started to discover the wonders and wealth of burning fossil fuels over 150 years ago? Last point(sorry for being bandwith hog on this post), but this is my favorite glacier picture, scroll to page 3. Is all of the above "unprecedented" just like the CO3 above 300 and just like the dramatic rise in temperatures pointed out this century? On page 3 the guy is standing on tree stumps created from a glacier that formed 3,000 yrs ago, this may seem like a long time, but is just a blink of the eye in geologic time. -
HumanityRules at 12:22 PM on 27 April 2010A visual depiction of how much ice Greenland is losing
I don't suppose you could add a depiction of the full size of the Greenland icesheet as well to put this in perpective? -
kdkd at 11:32 AM on 27 April 2010Skeptical Science Housekeeping: flags, printable versions, icons and links... lots of links
It might be an idea to put the source code for SS up in a version control repository somewhere. That way you can get your code autited, and members of the community might want to add features. Good work on the site by the way.Response: Being a novice at the whole open source community, my initial question to this is wouldn't it also be an opportunity for hackers to peruse the code looking for vulnerabilities? -
ubrew12 at 11:15 AM on 27 April 2010A visual depiction of how much ice Greenland is losing
Apologies if I got this link from this website (I forget sometimes), but this James Balog talk about time-lapse video of melting glaciers is quite stunning. The visual pyrotechnices start at minute 9. At around minute 14:30, he starts showing video from Greenland, and its truly amazing.Response: Thanks for the link. Here's the video embedded: -
Berényi Péter at 09:07 AM on 27 April 2010Has Arctic sea ice returned to normal?
There is a sharp conceptual difference between things measured vs. assumed based on a computational model like PIOMAS (Pan-Arctic Ice-Ocean Modeling and Assimilation System). In this sense sea ice extent is measured, volume is not measured, not even calculated. These values are based on a computational model, heavily interlinked with other models. It is extremely difficult to verify such a thing. However, they have a Seasonal Ensemble Forecasts of Arctic Sea Ice from April 2 to September 26, 2010 in three days steps made at the end of March (for scientific research and education only). I have made a backup, just in case. In five months we can check if sea ice extent prediction is correct or not.
That is, the model is falsifiable. We can put more faith into ice volume reconstructions provided the ice extent prediction in fact will not be falsified. The September 2010 arctic sea ice extent is predicted to be 5.3 million square kilometers. We'll see.
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