Guest commentary from Spencer Weart, science historian
Despite the recent announcement that the discharge from some Antarctic glaciers is accelerating, we often hear people remarking that parts of Antarctica are getting colder, and indeed the ice pack in the Southern Ocean around Antarctica has actually been getting bigger. Doesn’t this contradict the calculations that greenhouse gases are warming the globe? Not at all, because a cold Antarctica is just what calculations predict… and have predicted for the past quarter century.
It’s not just that Antarctica is covered with a gazillion tons of ice, although that certainly helps keep it cold. The ocean also plays a role, which is doubly important because of the way it has delayed the world’s recognition of global warming.
When the first rudimentary models of climate change were developed in the early 1970s, some modelers pointed out that as the increase of greenhouse gases added heat to the atmosphere, much of the energy would be absorbed into the upper layer of the oceans. While the water was warming up, the world’s perception of climate change would be delayed. Up to this point most calculations had started with a doubled CO2 level and figured out how the world’s temperature would look in equilibrium. But in the real world, when the rising level of gas reached that point the system would still be a long way from equilibrium. “We may not be given a warning until the CO2 loading is such that an appreciable climate change is inevitable,” a National Academy of Sciences panel warned in 1979.(1)
Modelers took a closer look and noticed some complications. As greenhouse gases increase, the heat seeps gradually deeper and deeper into the oceans. But when larger volumes of water are brought into play, they bring a larger heat capacity. Thus as the years passed, the atmospheric warming would increasingly lag behind what would happen if there were no oceans. In 1980 a New York University group reported that “the influence of deep sea thermal storage could delay the full value of temperature increment predicted by equilibrium models by 10 to 20 years” just between 1980 and 2000 A.D. (2)
The delay would not be the same everywhere. After all, the Southern Hemisphere is mostly ocean, whereas land occupies a good part of the Northern Hemisphere. A model constructed by Stephen Schneider and Thompson, highly simplified in modern terms but sophisticated for its time, suggested that the Southern Hemisphere would experience delays decades longer than the Northern. Schneider and Thompson warned that if people compared observations with what would be expected from a simple equilibrium model, “we may still be misled… in the decade A.D. 2000-2010.” (3)
The pioneer climate modelers Kirk Bryan and Syukuro Manabe took up the question with a more detailed model that revealed an additional effect. In the Southern Ocean around Antarctica the mixing of water went deeper than in Northern waters, so more volumes of water were brought into play earlier. In their model, around Antarctica “there is no warming at the sea surface, and even a slight cooling over the 50-year duration of the experiment.” (4) In the twenty years since, computer models have improved by orders of magnitude, but they continue to show that Antarctica cannot be expected to warm up very significantly until long after the rest of the world’s climate is radically changed.
Bottom line: A cold Antarctica and Southern Ocean do not contradict our models of global warming. For a long time the models have predicted just that.
(1) National Academy of Sciences, Climate Research Board (1979). Carbon Dioxide and Climate: A Scientific Assessment (Jule Charney, Chair). Washington, DC: National Academy of Sciences.
(2) Martin I. Hoffert, et al. (1980) J. Geophysical Research 85: 6667-6679.
(3) Stephen H. Schneider and S.L. Thompson (1981) J. Geophysical Research 86: 3135-3147.
(4) Kirk Bryan et al. (1988). J. Physical Oceanography 18: 851-67. For the story overall see Syukuro Manabe and Ronald J. Stouffer (2007) Journal of the Meteorological Society of Japan 85B: 385-403.
Roger, your question is rather broad and vague. What aspect of the science are you seeking to falsify? See, that is precisely the problem when you have a theory that draws support from such a broad range of phenomena and studies as does the current theory of climate. It is rather like saying, “How would we falsify the theory of evolution?” When a theory has made many predictions and explained many diverse phenomena, it is quite difficult to falsify as a whole. You may be able to look at pieces of it and add to the understanding. Climate science is quite a mature field; future revolutions are quite unlikely. Changes will come but will likely be incremental. It is very hard to envision a development that would significantly alter our understanding of greenhouse forcing unless our whole understanding of climate is radically wrong, and that seems unlikely.
B Clarke in #40 says that GW on Mars casts doubt on a human cause for GW on Earth. This is a long-discredited argument that sometimes resurfaces – for starters, please enter “Global warming on Mars?” (with the question mark) into the search box at the top of this page.
Here is some relevant news about the Antarctic:
Patrick Hadley complains about the need to observe climate over long times. Isn’t it ironic that for the past 20 years, skeptics have been telling us that we don’t have enough data to establish a trend, and now that the trend is finally obvious to all but the most myopic, they complain about climate observations taking too long.
Magnus (45) — (BTW: The 0.1 degrees C trend since 1980 isn’t historically exceptional, all proxies shows without any doubt. The reason for this upward trend can be the same as previously in history.)
I’ll not take your word for it. Cite peer-reviewed literature, please.
#21 Jim Cripwell said, “If you do the right sort of analysis of world temperature anomaly against time over the last 30 years or so, it is clear that temperatures have gone through a shallow maximum, and the temperature/time graph, as of now, is negative.”
Really? Take a look at the following article by Tamino, based on NASA GRISS compilations, Jim. I think you will agree that your statement cannot be substantiated. Unless by “now” you are referring to some short term cherry-picked part of the temperature graph that is presently going down. But then there are numerous occasions over the last 30 years or so when that has been the case – that is why it is necessary to look at longer term trends, and rather than short term variations.
http://tamino.wordpress.com/2008/01/09/dead-heat/
OK, see the problem I have is this:
http://www.ucsusa.org/global_warming/science/early-warning-signs-of-global-warming-arctic-and-antarctic-warming.html
First sentence: “Climate change is expected to be more rapid and severe in polar regions compared to other places on Earth.”
One paragraph down: “Although there is some variability among models, most projections indicate that increased CO2 concentrations will lead to a polar warming that is greater than the global average, with more warming over land than sea and the maximum warming occurring in winter (Kattenberg et al., 1996). ”
So, which is it? Do the models predict magnified polar (this includes Antarctica, all of it) warming or not? That article indicates warming should be GREATER over land. Antarctica has land, lots of it. It should be warming a ton. But it’s not. Can’t have it both ways, and claim all is hunky-dorey…
Which. Is. It?
[Response: Don’t just pose rhetorical questions. Have a look and see: Polar amplification or here for some raw output. Try looking at the expected trends from 1970 to 2003. – gavin]
#21 Jim Cripwell said, “If you do the right sort of analysis of world temperature anomaly against time over the last 30 years or so, it is clear that temperatures have gone through a shallow maximum, and the temperature/time graph, as of now, is negative.”
Really? Take a look at the following article by Tamino, based on NASA GRISS compilations, Jim. I think you will agree that your statement cannot be substantiated. Indeed, there is no support for it from the data.
http://tamino.wordpress.com/2008/01/09/dead-heat/
Patrick:
We should have statistically significant results in about 7 years, though it may be as long as 22 years if variation suddenly becomes lower than it has been in the past. See Tamino’s recent post on the subject here: http://tamino.wordpress.com/2008/01/31/you-bet/
You simply can’t determine anything significant about a long-term trend from a single new year of observations unless it differs quite a bit from the trend. If 2008 turns out to be the same temperature as 1908, something might be fishy with the whole warming trend. If its the same temperature as 2003 or 1993, its not that meaningful.
Regarding Dr. Pielke’s question:
“What behavior of the climate system would contradict models of global warming? Specifically what behavior of what variables over what time scales? This should be a simple question to answer.”
I don’t think this so simple, because there are degrees of contradiction. I agree with the following poster, that most of the evidence that would contradict the models, can only be discovered by thoroughly understanding the models. The contradiction might only affect one attribute of the climate system, and thus only a part of the model.
However, there are some purely statistical tests on data compared to a system forecast, that don’t depend on the model behind the forecast. Businesses and manufacturers have used SPC (Statistical Process Control) for years to test data and identify statistically meaningful data excursions that indicate the system is changing. Usually, they don’t have a mathematical model that describes their system, just the stream of data from the system output. Typically, the most common statistical test used, is to construct control limits three standard deviations above and below the mean.
So for example, if the global temperature anomaly suddenly dropped about three standard deviations below the long term running mean, this event would be less than 0.3% likelihood in a normal distribution. Based on the posts here, it appears the 15 year running means, seem to align pretty well;
https://www.realclimate.org/images/giss-15yr.jpg
so we might use that.
The last 35 years of data show a yearly standard deviation of about 0.1 deg, so about a 0.3 deg C drop below the 15 year mean, for a single year data point, should trigger a search for a “special cause”. Currently the 15 year anomaly is approximately positive 0.35 deg C, so we need to see a drop in the anomaly down to around 0.0 deg C to get concerned that the models might be contradicted by the data.
Of course, if it is a known forcing from an unpredictable event, such as a volcanic eruption, then the forecast output should be adjusted for the known forcing, before comparing with the actual data.
(Curious question- Did you adjust forecasts made prior to Pinatubo in 1991, for the estimated effect of that event, before comparing to actual results, in the work that you have done?)
Another statistical test often used, is a 7 point sequence of steadily rising (or falling) data. This apparently has about the same likelihood as a three sigma event, in an normal distribution. So, if we see seven years in a row, where the temperature anomaly is falling lower and lower each and every year, while GHG concentrations are rising, this would trigger the search for a special cause.
There are other statistical tests that don’t require a review of the model behind the forecast, to trigger special cause searches.
I see from your background, you have a degree in Mathematics, so you can probably get up to snuff on this fairly fast. Engineers who run into this kind of question, typically seek out a well qualified and experienced statistician to help with the effort. I have pretty much expended my knowledge level on this, but have worked with some statisticians in the past, who do this kind of work. There was even someone here on an earlier discussion board, who worked in the nuclear industry at one time, and who used statistical tools that adjusted for steadily rising trend data, like encountered here.
But if you aren’t satisfied with purely statistical tests on the measured data, then I am afraid the previous poster is correct… You need to understand all the details of the models themselves, to know when, where, and to what extent the model has been contradicted by the data collected.
So far, there doesn’t appear anything in the global temperature data that is statistically meaningful in questioning the models. On the contrary, the models appear to be predicting global temperatures almost as good as a perfect forecast would have (try regression analyses on the last 8,10,12,15 years of global temperature anomaly data, and compare these trend lines with the model trends).
Of course the modelers here have the advantage on us, and can see inconsistencies, that we can’t, because they know the models. They recognize the models were too conservative regarding Arctic melting. Another example: They apparently don’t have the positive feedbacks from methane released from permafrost melt in their models yet, although I understand this might be coming in the next round of modeling. So like it or not, we need to hear their viewpoints, especially since their track record looks outstanding, so far. And the information that they are talking about seem to indicate that over time, as the positive feedbacks kick in, the current models are too conservative,
[edit]
[Response: There is no mystery as to why persistent off-topic questions don’t make it through. If you are interested in radiative transfer read the relevant posts on that. – gavin]
Just a couple of things:
Regarding the ‘ice’, it’s important to remember to distinguish between volume and surface area. In this vein, Christopher Booker has been at it again in the ‘Sunday Telegraph’ (U.K.) just recently, pouring some scorn over the ‘alarmist’ comments made after the record reduction of sea ice in the Artic last year. Likewise, it might be possible to try to confound predictions for the Antarctic, or rubbish the models for that matter, by failing to make a distinction between these two attributes of the ice.
Another point to bear in mind is the (probably) non-linear response to warming of the submarine ice, something I have tried to highlight before. The effects of melting of this relict ice, much of it likely to be composed of fresh rather than salt water, could lead to some really quite peculiar behaviour in the mixing zones, which again might be used as ‘evidence’ that the models, and ‘global warming’ warnings generally, are unreliable and unscientific.
Thus, from the skeptics’ point of view, every model failure confirms their opinion that the science is highly suspect, and we have nothing to worry about; likewise, every model success is treated as a fluke, and simply further evidence that the scientists are covering up/fiddling the figures/etc. etc.
In response to the query in #38:”I have asked many times and never received an answer here: What behavior of the climate system would contradict models of global warming? Specifically what behavior of what variables over what time scales? This should be a simple question to answer.”
Any one of the following partial list of variables and the resultant effects would contradict models of global warming.
Temperature measurements that indicate that the troposphere is cooling and
that the stratosphere is warming.
The measurement of temperatures at ocean depths of about 1000 meters or more
showing cooling.
Measurements of sea level begin to lower due to temperature contraction.
The lowering of the tropopause.
A migration of species both botanical and zoological toward the equator
A restoration of mountain glaciers to pre 1950 levels.
A lowering of temperatures in the permafrost from the present temps to prior levels.
This is just a partial list of factors. There would be different time scales for the different climate phenomena.
Was wondering about that. My wife is in the Ross Sea right now with a small group and the previous cuise from last month reported the ice pack had not melted as much as prior summers, though the current voyage seems to have penetrated further than last month’s.
This is the latest refutaion paper being passed around.
http://arxiv.org/abs/0707.1161v1
Falsification Of The Atmospheric CO2 Greenhouse Effects Within The Frame Of Physics
Authors: Gerhard Gerlich, Ralf D. Tscheuschner
(Submitted on 8 Jul 2007 (this version), latest version 11 Sep 2007 (v3))
Abstract: The atmospheric greenhouse effect, an idea that authors trace back to the traditional works of Fourier 1824, Tyndall 1861 and Arrhenius 1896 and is still supported in global climatology essentially describes a fictitious mechanism in which a planetary atmosphere acts as a heat pump driven by an environment that is radiatively interacting with but radiatively equilibrated to the atmospheric system. According to the second law of thermodynamics such a planetary machine can never exist. Nevertheless, in almost all texts of global climatology and in a widespread secondary literature it is taken for granted that such mechanism is real and stands on a firm scientific foundation. In this paper the popular conjecture is analyzed and the underlying physical principles are clarified. By showing that (a) there are no common physical laws between the warming phenomenon in glass houses and the fictitious atmospheric greenhouse effects, (b) there are no calculations to determine an average surface temperature of a planet, (c) the frequently mentioned difference of 33 degrees Celsius is a meaningless number calculated wrongly, (d) the formulas of cavity radiation are used inappropriately, (e) the assumption of a radiative balance is unphysical, (f) thermal conductivity and friction must not be set to zero, the atmospheric greenhouse conjecture is falsified.
Comments: 113 pages, 32 figures, 13 tables
Subjects: Atmospheric and Oceanic Physics (physics.ao-ph)
Cite as: arXiv:0707.1161v1 [physics.ao-ph]
Not peer reviewed and not endorsed either.
[Response: See here. – gavin]
Thanks for the great post Mr. Weart.
This is my first reply here, your post made me think of something that I’ve been pondering on lately.
This is similar to other topics I’ve read recently. On almost every website I’ve visited, there are so many “yah, but…” arguments. And after some reading, I find out that in fact these are sometimes expected results.
I’m curious about something, but haven’t really been able to parse the information out of so many different opinions on the matter. It’s the counter arguments. Do they have the same predictive capabilities as the theory behind greenhouse gases? I’ve heard it could be the sun(like changes in TSI and sunspots, and GCR’s), but it appears that the smart folk here have some issues with various aspects, like statistical fudging, and even lack of basic stats like correlations.
Things like the Antarctic issue you’ve raised, the stratospheric cooling, the trends in night time versus daytime temperatures, and so many other special topics. Is there any mechanism from these counter arguments that could be causing these changes? Or would it be more likely that many different mechanisms are taking place in tandem? It seems to me that it might be even more difficult to show the fingerprint of this tandem or additive effect. Or at least as hotly contested as other number crunching exercises on this subject.
I’ve read some of the web resources which have collected all the arguments in one place, but I haven’t found an answer for this yet.
I hope some of the smart folk here can help me find links or explanations, I would greatly appreciate it!
1. What is the percentage of purple areas in Rignot study yow cited to the total ice mass of Antarctica?
2. How close are the major melt areas to known or recently discovered volcanoes?
3. Are the studies conclusions contradicted or mitigated by 2007 and early 2008 data?
4. The study states: “Even in Est Antarctica, where we find ice mass to be in near balance, ice loss is detected in its potentially unstable marine sectors, warranting further study.” My recollection is that studies show a net increase in ice mass throughout the continent except for an area of about 5% of the land mass. Which analysis is correct?
5. the study emphasizes ice flowing from drainage basins over 85% of the coastline. Is nto the coastline the only area where such observations can be made?
6. What do studies show regarding accretion or loss of ice mass show for years prior to 1996? Is not the continental and sea ice accretion for 2007 record breaking?
I presume that this comment will be deep sixed?
It would be worth putting up an temperature anomaly prediction map from one of the GCMs to help people get their heads around this. While you are at it, put in the plots of observed temperature for the Northern and Southern Hemispheres, the Arctic and the Antarctic.
I wrote a long, carefully stated reply to Roger Pielke, Jr.’s latest opinion piece on his Prometheus blog. It was in regard to his question here and a very few of the replies. I found his piece to be most disappointing and I explained why in some detail.
To no avail. His comment posting program is broken. Says something I suppose.
But I want to thank those volunteers here, mostly amatuers, who so nicely and carefully responded to Pielke’s question. I found replys quite informative.
I agree with the post on the oceanic heat uptake and its role in reducing or delaying Southern Hemisphere warming. However, it should be noted that over the Antarctic continent itself, one must consider the atmospheric circulation, and in coastal areas, the regional sea-ice extent, to explain recent temperature trends. The continental interior doesn’t really “see” the ocean. It does see the increasing GH gasses, but for the moment, atmospheric circulation is likely playing the larger role in temperature trends.
The surface energy balance is strongly tied to the atmospheric circulation, and requires a large poleward heat transport by the atmosphere. Otherwise, the interior would be much, much colder than it already is. Small changes in the circulation can greatly impact temperature trends. As has already been discussed elsewhere on RealClimate, cooling in the middle of Antarctica has been explained by an increasingly strong polar vortex, which isolates the continental interior.
In current IPCC models, Antarctica doesn’t warm up any more than any other Southern Hemisphere continent. There is no polar amplification like in the Arctic. There is warming – the cooling that the post discusses pertains to parts of the Southern Ocean. The models may somewhat underestimate the role of circulation, and overestimate other feedbacks, and there are some papers coming out on this.
Gerlich & Tscheuschner
Learn slow.
These guys have been publishing the same crap for years now. They get shot down and six months later they’re back with more. A cautionary tale: Don’t try to refute what you don’t understand.
OK, good to have rebuttals to simplistic objections about climate change. The skeptics also talk about cold temperatures this winter, which means N. hemisphere of course! So for comparison, how hot is summer in S. hemisphere this year?
A couple of belated questions that don’t add up in my mind (or I just missed it/forgot it).
1) Is the mechanism for atmosphere transporting heat to the ocean all back IR radiation? Or doe conduction or convection (???) play any part?
2) Why does the heat added to the surface of the ocean transport itself deeper. Conduction and radiation seem poor transporters (are they here?). Convection is going the wrong way unless it is gettting mixed through upwelling. And if so, why do you get upwelling just because the surface is warmer.
3) The logic of the Southern oceans heating at the surface slower than the northern hemisphere seems understandable (assuming the above), which one could then go the next step that Antarctica would warm (much) slower than the Arctic. But why would it get colder??
Apologies to those who asked questions directly of me: I have been on jury duty and am also trying to carry on my regular job by email etc., so I haven’t had time to respond here. My article is intended only to explain that HISTORICALLY, even models very primitive by modern standards showed no strong Antarctic warming. In science, as Dr. Pielke surely knows, actual prediction trumps just about anything else, and it’s striking that for decades models have been roughly right about ice retreat in the Arctic and non-retreat in the Antarctic.
A quick take on CURRENT models may be found in the IPCC Fourth Assessment Report – Scientific Basis, at http://www.ipcc.ch, see especially fig. 8.10. They point out that modeling Southern Ocean sea ice cover is tricky and uncertain, with a wide spread among different models, but the observed ice extent is smack on the median of the ensemble of models.
This may be just slightly off-topic, but I’d like to observe that Dr. Weart’s command of the historical perspective is absolutely dynamite. He writes so clearly and accessibly, it makes me mad that I don’t find stuff like this in more popular venues. Thank you.
Ray Ladbury (30): “Magnus, #15 and #16, I will give you the benefit of the doubt that you are not a native English speaker, because your take on this article is totally a product of your own fevered imagination. There is plenty of evidence for warming–and it is mostly from the Northern Hemisphere, as predicted by the models.”
I don’t deny any warming anytime! (Speak of imagination…) If you read my comment again carefully you may see (I don’t know if you do, but mayde…) that I try to be logical where it’s hard to find any logic, and you may also recognize it ends up in some irony.
Ray Ladbury: “So since the models are being verified by the evidence, explain exactly how there should be any talk of falsification?”
The model has not been verified by evidence. The warm is too weak for even the lowest warming scenario. Watch this graph:
http://bp1.blogger.com/_xTUB8vsmURU/Rx4kTT7YNKI/AAAAAAAAACA/vWY_0H1iXOA/s1600-h/gse_multipart51047.png
Also the heat distribution of heat in the models on latitude and altitude differs so much that there is no correlation. This graph with prediction on the upper left picture you can compare with satellite data and radio sond data ;) :
http://bp1.blogger.com/_xTUB8vsmURU/Rx4kTT7YNKI/AAAAAAAAACA/vWY_0H1iXOA/s1600-h/gse_multipart51047.png
Or the predictions of the distribution of warming in the atmosphere in four climate models:
http://bp3.blogger.com/_xTUB8vsmURU/Rx4iIz7YNII/AAAAAAAAABw/j_7KWIRBfxg/s1600-h/whatgreenhouse_5.jpg
…and the actual result due to radio sond data HadAT2:
http://bp1.blogger.com/_xTUB8vsmURU/Rx4jsT7YNJI/AAAAAAAAAB4/35xMFFP2nHE/s1600-h/whatgreenhouse_6.jpg
No model has lasted for more than 1 or 2 years until it’s been totally wrecked. This post is typical ad hoc, which is typical in “climate science”.
[Response: First off, the ensemble mean or long time scale is not the field to compare to the single realisation of the real world (as discussed previously). Secondly, all of the radiosonde data set are being reassessed to deal with known biases. If those revisions end up looking more like the model means, will you then accept that the models have some validity? I don’t think we will have that long to wait… – gavin]
Rod, how warmth gets into the deep ocean — same way oxygen does, there are areas where surface water sinks from the top to the middle and bottom.
http://scholar.google.com/scholar?num=100&hl=en&lr=&newwindow=1&safe=off&scoring=r&q=ocean+circulation+climate&as_ylo=2007
Re #73:
What happens is that the Sun heats the ocean surface. It has become more difficult to get rid of this heat by long wave radiation, so yes, you could say that it is back IR radiation from the atmosphere. I suspect this is dominant just due to the huge amount of solar energy impacting the Earth all the time. How big (or small!) the contributions of the other two are, no idea.
Yes, convection doesn’t work here as the surface is warmer (but contrary to air, the density differences are very small). I understand that it is the slow overturning due to global circulation (wind driven?) that carries the warm surface water to depth (and brings up cold deep water in other places). But this is a very slow process as is always stressed in the literature.
I’ll leave question 3 to the experts :-)
According to Manabe and Stouffer (2007; see the link in my comment above, now #22), the model used in the study of Hansen et al. (1988, J. Geophys. Res. 93, 9341 – 9364) did not include the ocean circulation. The penetration of heat into the deep ocean was approximated as diffusion. Though I do not know details, perhaps they had no reason to assume the diffusion in the Circum-Antarctic Ocean more effective than in other parts of the world ocean. So it is no surprise that the Circum-Antarctic Ocean warmed up in their projection. Now we regard that that version of their model could not reproduce the actual spatial feature of time-dependent warming, even though their projection was not bad in the global average sense.
On the other hand, the model of Bryan et al. (1988, ref (4) of the original posting) included the full ocean circulation, and, even though the land-sea configuration was idealized, it had the counterpart of the Circum-Antarctic Ocean, and they observed deep penetration of heat there in their model.
A little later, experiments with models which had full ocean circulation with realistic land-sea configuration were conducted (e.g. Stouffer, Manabe and Bryan, 1989, Nature, 342, 660 – 662; Manabe, Stouffer, Spelman and Bryan, 1991, J. Climate, 4, 785 – 818; Washington and Meehl, 1989, Climate Dynamics 4, 1 – 38), and scientists had more confidence in delay of warming in the Circum-Antarctic Ocean.
Somewhere above was some discussion about snow and cold in US, I think…
Here in southern Finland the passed January was 4…5 degrees C warmer than average, snow came and went and now we are near the February 15th and there is still no snow. Usually there are bouts of cold around 15..20 degrees, 10..20 cm of snow etc; there haven’t been a single so cold day so far. Sea ice in Baltic is very low compared to average etc.
So if somebody thinks that exceptional snow in China or some similar occurrence is some kind of evidence against warming, well…
I just would like to take this opportunity to thank Ray Ladbury, Timothy Chase, Tamino, Barton Paul Levenson, and many, many others, as well as the scientists at RealClimate, for volunteering so much time and effort to this website. Although I have been concerned about global warming for around two decades, I have learned so much checking in on this site each day.
As an aside, after Jim Galasyn posted the article in Anchorage Daily News, “Polar ice pack loss may break 2007 record” by Tom Kizzia [#33], I emailed my old friend Tom to let him know about the posting. I told him that after my wife retires in 3 1/2 years, we would be returning to Alaska for an extended visit, and that I hoped Alaska wouldn’t be changed too much by then. Tom replied, “I’m sure Alaska will still be here – you can bask on the sunny beaches and shade yourself under the palms.”
Pardon this bit on humor, but Tom Kizzia has written a number of articles about the amazing changes Alaska has seen in the past few years. Models aside, those living in the far north are experiencing a major warming. While we may quibble about how accurate models are, or if there is some recent cold weather, those who live in a climate dependent upon permafrost are seeing their infrastructure collapse. As Bob Dylan wrote, “you don’t need a weatherman to know which way the wind blows.”
Thanks for all the effort put into RealClimate. This website is important. It will make a difference. Thank you.
Just about twelve months ago, Al Gore, appearing before a Congressional
subcommittee said “The planet has a fever. If your baby has a fever,
you go to the doctor. If the doctor says you need to intervene here,
you don’t say, well I read a science fiction novel that tells me it’s
not a problem. If the crib’s on fire, you don’t speculate that the baby
is flame-retardant. You take action.” In view of the GISS + SST data from January 2008 coming in at 0.12C, the coldest month since something like 1996, and half a degree cooler than January 2007, I wonder if anyone has any comments.
In 58 Slioch writes “Really? Take a look at the following article by Tamino, based on NASA GRISS compilations, Jim. I think you will agree that your statement cannot be substantiated. Indeed, there is no support for it from the data.” We have been round this mulberry bush many times. The reference you gave uses ONLY the NASA/GISS data. I use all five data sets (URLs on request). Up to about two years ago, the trends from all the data sets were in rough agreement. In the last two years or so, the NASA/GISS data gives a different trend from the others. It is true that NASA/GISS shows that temperatures are still rising, but the other four sets show temperatures are falling. One wonders what effect the January 2008 data from NASA/GISS presages. I would note, as I have done several times, that there is no study which compares and contrasts the different data sets, so we dont know which one is “best”. It may well be that NASA/GISS has got it right, but I suggest the preponderence of evidence is that it is the outlier. Time will tell. I do wish people on RC would desist from ONLY quoting NASA/GISS temperatures, as if they were some sort of Bible. There are five data sets, not one.
[Response: We have regularly used all 3 surface temperature data sets when it makes sense to do so. And there have been a number of papers on the differences (Vose et al, for instance). The satellite data sets are not the same quantity even though they are highly correlated. – gavin]
Re #73 Rod B, question 2: read Carl Wunsch, ocean circulation guru (where my vague recollections came from):
http://www.sciencemag.org/cgi/content/full/298/5596/1179
Re #38: the dichotomy valid/invalid is false for testing climate models. Just like everybody is a believer, and atheists just hold the belief that God does not exist, so everybody is a climate modeller too. The “models” of the modelling sceptics just are 1) simple, 2) implicit, 3) logically inconsistent and/or 4) not (easily) falsifiable.
An example of the last is the “model”: “nah, it’s just natural variation”. You can throw any data at it and it will happily munch it up.
Before asking what kind of observed behaviour would falsify an existing climate model, one should state an alternative hypothesis (i.e., model) that would be verified by such a rejection. And it better be logically consistent (i.e., not explain temperature increases by an increased forcing that didn’t actually increase, like the Sun), have predictive power (i.e., be falsifiable), and do a better job at explaining all observed behaviour. Validation is intercomparison.
Here is again the old, and coming from a scientist intentional, rhetoric falsehood of equating uncertainty in a model with that model being worthless. It is precisely the realistic assessment of uncertainties that makes scientific work scientific.
Correction to URL in 74: that’s http://www.ipcc.ch without a comma. The specific reference is to chapter 8 of the “Physical Science Basis,” pdf online here
#45 Magnus
“#24 Cobblyworlds: “Climate is not weather.”
That’s a standard phrase indeed. Didn’t heard about it in the alarmism of El Nino year 1998…”
I don’t know about that, GW wasn’t on my radar then, I was a sceptic until around 4 years ago. Currently (as per usual) it’s the denialists who’re trying to use one outlier to state a false case – GW stopped in 1998 a la Monckton et al.
The reason you can’t consider weather is that weather will not be the same even between different runs of the same model. If we had multiple earths then you’d find the same effect.
Needless to say I don’t accept that on the relevant timescales the projections are overshooting, that’s because I see no evidence for that, IMHO it’s too close to call right now. However the situation in the Arctic alone implies current projections will be more likely to undershoot for the northern hemisphere.
Re #76 where Gavin responds “… all of the radiosonde data set are being reassessed to deal with known biases. If those revisions end up looking more like the model means, will you then accept that the models have some validity?”
Gavin,
Why should we accept those revisions when they have not yet been published, yet you reject the current data which has?
The MSU data has already been revised to make it more like the models, here but the radiosonde data still did not agree, so a proposal to alter that was also made Sherwood et al. 2005 . But this correction to the radiosonde data was based on a circular argument, of which the authors were probably unaware, but it makes me very reluctant to give a “blank cheque” for any other corrections by scientists who were unable to spot such a weakness.
The logic of the Sherwood et al. paper goes like this: Following the “correction” to the MSU data it is only the radiosonde data that disagrees with the models. Therefore there must be errors in the radiosonde data. We know that no correction is being applied for solar heating of the instruments during the day, so we should apply a correction for that but we do not know how much. So we correct it to fit the decadal trend, and eureka it fits with the models.
But the whole problem with the models is that they are equating solar (diurnal) heating with greenhouse gas (decadal) heating. So when the scientists “correct” the radiosonde data so that diurnal and decadal trends are the same, they are making it match the models because both now include the same error.
Of course I am arguing that solar heating and greenhouse heating act via different mechanisms. That is so very obvious that it is very difficult to counter the nonsensical argument that it is untrue.
[Response: You miss my point – it was a hypothetical. In the case that the revisions come in and end up more closely agreeing with the models (note the ‘if’), would Magnus be prepared to accept that the models have validity? If the answer is yes, then that would demonstrate an open mind and a commendable willingness to accept new evidence. If the answer is no, then there is no point in further discussion. But since these revisions are indeed underway, this won’t remain hypothetical for much longer. – gavin]
Re #82
Jim, no. This is a climatology site. Most people try to hide their ignorance, it would become you to do the same.
Niel B:
Can’t tell you for the entire southern hemisphere, but in south-east Australia it seems like it’s been a relatively mild summer. Few really scorchingly hot days here in Victoria, and none of the horrendous fires that we have been hit with in recent years. However according to this page at the Australian Bureau of Meteorology, January 2008 was our hottest on record.
Being a La Nina year, we have had some reasonable rainfall in some areas of the east and north east for a change. Sadly though, the Murray Darling Basin is in a worse state than ever. It appears that Australia’s largest river system, is in a state of ecological collapse.
The outlook for Feb-April is here
The forecast is for near to historically average daytime temperatures throughout the continent, and for significantly warmer than average nighttime temperatures in the south-west and north-east.
Jim Cripwell asks: “In view of the GISS + SST data from January 2008 coming in at 0.12C, the coldest month since something like 1996, and half a degree cooler than January 2007, I wonder if anyone has any comments.”
Might I suggest tuning in the weather channel for even more up-to-the-minute data?
Actually, Martin Vermeer brings up an excellent point. Since predictions of most models are statistical, most tools of verification are comparative. That is, you have to compare a model to some alternative. In that sense anthropogenic causation is very much like the theory of evolution, where any putative alternative has been pretty thoroughly bitchslapped by the evidence.
Bah! Here in Denver, the alarmists claim that we’re in a warming trend which began during the final week of January and project that within four months we’ll be swimming in our shorts. And yet, today is nearly 40F colder than yesterday. So much for your vaunted “science”!
Re Gavin’s response to #88
Au contraire Gavin, I think it you who has missed my point :-)
Your question was more of the “Have you stopped beating your wife yet? Answer Yes or No” category, than a reasonable request for information.
Perhaps you could answer this question. If the revisions do not find agreement with the models will you accept that “that different physical mechanisms control amplification processes on monthly and decadal time scales, and models fail to capture such behavior?” Quote from Santer, B.D. et al. & Schmidt, G.A. 2005 .
In other words will you accept that the models are wrong?
[Response: Wrong question. The models are always wrong, the issue is whether they are useful. At any one time there are multiple model-data discrepancies. Take the double ITCZ issue. There is no question that the models are wrong in showing that. That makes statements about tropical rainfall variations in future open to significant uncertainty. However, the tropical tropospheric trends issue is different – first off the observed time-series are short and the data suspect. If this is taken into account there actually isn’t much of a discrepancy (since any signal is very indistinct). Secondly, the theoretical basis for expecting close to moist-adiabatic behaviour is very strong. I therefore predict that the data revisions will bring models and data closer into line. If however, the signal strength increases and a real discrepancy remains, then of course that will prompt a re-evaluation of the model physics. My question to Magnus was not a trick. There is one perfectly good answer (unlike your analogy). – gavin]
#84 Re Carl Wunsch,
Prof. Carl Wunsch’s publications page is here: http://ocean.mit.edu/~cwunsch/
It has the 2002 paper “What is the Thermohaline Circulation” downloadable without charge. And loads more interesting stuff besides.
“Leonard Evens tells us that it will take 30 years of declining temperatures before he would even begin to doubt the validity of the current climate models. He is certainly to be congratulated on demonstrating that he is indeed a true believer, but do the rest of us really expected to have to suffer all the negative consequences of carbon-reduction policies for 30 years before we are allowed to be sceptics?”
No I mentioned other tests, and Barton mentioned many more. Also, the IPCC Reports have chapters devoted to evaluation and validation, which you are free to look at. But if you insist on a predictive test which is based on future observations, it is an unfortunate fact that it will take a while. For some skeptics, no amount of evidence will suffice, so it will take forever. The climate system has various time lags built into it, so it takes time for any effects to be completely clear beyond any possible doubt. There have been some short term predictive examples, such as Hansen’s use of his model to predict the effect of Mt. Pinatubo in advance, but skeptics find reasons for rejecting that.
In thirty years, I think the effects of global warming will be so clear, few will pay attention to skeptics. But at some point, and I hope it is well before that, we must decide what to do on the basis of the evidence we have. Taking action to limit greenhouse gas emissions may entail costs, but doing nothing may also entail costs. If I am right and we wait to decide to limit emissions, than I think the costs of adaptation will be truly enormous, much greater than the costs of more modest measures adopted now. But suppose I am wrong and you are right. Most of what we should do to limit global warming in the US and much of the rest of the world should also be done for other cogent reasons. In the US we should reduce our reliance on oil for reasons of national security. Moreover, the costs of limiting greenhouse gas emissions are also unknown. You take it as axiomatic that they will be ruinous, but on what well established predictive models do you base such a conclusion? While it is not completely analogous, the same claims were made about the costs of phasing out CFCs (and by some of the same people), but we did it anyway in order to limit loss of stratospheric ozone, and no economic disaster ensued.
Jim Cripwell asks: “In view of the GISS + SST data from January 2008 coming in at 0.12C, the coldest month since something like 1996, and half a degree cooler than January 2007, I wonder if anyone has any comments.”
You appear to be sweet on a La Nina. You’d better send her a Valentine today because next year she will be long gone, and I don’t imagine you’ll like her alternate.
As posted previously, the GISS is reporting a -.75 degree (C) drop in global temps from Jan 07 to Jan 08.
http://data.giss.nasa.gov/gistemp/tabledata/GLB.Ts+dSST.txt
And a steady decline during the entire year.
This is the sharpest single year temp drop in the entire GISS temps records.
More severe winter weather has been experienced first in the Southern Hemisphere last Jun & Jul during the SH winter, and currently in the Northern Hemisphere winter from North America, Europe, Russia, China Middle East, etc.
Many are starting to claim that this has to do with the current solar minimum and delayed start of Solar Cycle 24.
http://www.dailytech.com/article.aspx?newsid=10630
http://ibdeditorial.com/IBDArticles.aspx?id=287279412587175
http://en.rian.ru/analysis/20080103/94768732.html
http://www.investors.com/editorial/editorialcontent.asp?secid=1501&status=article&id=287279412587175
http://www.popularmechanics.com/science/earth/4248062.html
http://news.independent.co.uk/sci_tech/article3223603.ece
http://www.britsattheirbest.com/001645.php
The “Skeptics” claim that the Maunder Minimum, and decreased solar activity, was the cause of the Little Ice Age.
And according to their theories, it is this current prolonged solar minimum that is causing the current significant global cooling trend.
Sounds to me like what is going on with temps and the Sun is more than just a “coincidence” and is the best evidence yet that the Sun is driving Earth’s temps more than CO2 levels.
Any comments?
[Response: Yes. These claims are ridiculous. There is so far nothing exceptional about this solar minimum. Depending on the composite TSI you look at it is either slightly below, slightly above or the same as the last solar minimum. No other index shows anything extraordinary. Plus the idea that there is some instant response of the whole planet to a tiny change in irradiance is silly (some of the same people were claiming that a fifty year lag was required not six months ago). And frankly, anyone who makes a climate trend statement based on the presence of a single large La Nina pattern is going to look rather foolish in 12 months time. – gavin ]
#83 Jim Cripwell
So Jim, you apparently agree:
1. That the NASA GISS series does not support your claim “that temperatures have gone through a shallow maximum, and the temperature/time graph, as of now, is negative.”
2. That the HadCRU and NCDC series also did not show that effect until two years ago, since you agree that “Up to about two years ago, the trends from all the data sets were in rough agreement.” You don’t mention your other two series – is that the “satellite data sets” Gavin refers to?
So, you entire case is based on just two years worth of selected data? As I pointed out in my first draft (#56 that was unintentionally published): “you are referring to some short term cherry-picked part of the temperature graph that is presently going down. But then there are numerous occasions over the last 30 years or so when that has been the case.”
Tamino discusses this matter further here:
http://tamino.wordpress.com/2008/01/31/you-bet/
and helpfully provides the following graph of all three series plotted together:
http://tamino.files.wordpress.com/2008/01/trend2.jpg
which shows just how unsubstantiated your case is.
Why not take the “bet” Tamino suggests. Then you can come back in several years time when you will have more than a couple of years data. Until such time, you are just talking about noise on a graph.
Re #97
According to the Oceanic Niño Index as published by the NOAA it has been 6 years since the last La Nina event and 25 months out of the last 5 years have qualified as La Nino. Still, the SST are on a 7 year downward trend. There may or may not be a snap-back coming but either way your smart aleck remarks are misplaced.