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Geo Guy at 05:30 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
One of the criteria needed for an ice age to occur (beyond lower temperatures) is precipitation. As long as the arctic ocean remained frozen year round, the arctic climate was arid with very little annual precipitation. Now with the arctic ice disappearing, we will likely see greater precipitation happening in the northern hemisphere. During the last ice age, a part of the arctic waters remained open, thereby fueling the snow which accumulated as ice. Another point - the cold air patterns that engulfed North America this past winter - dipping as far south as Houston Texas which got snow, followed a similar pattern to the continental glaciers that covered a part of North America some 12,000 years ago. Finally, assuming that the patterns depicted in the temp graph illustrating temps for the past 420,000 years, it would appear that we (the earth) are due a relapse of falling temperatures which could be the initial stages of an ice age.Response: "assuming that the patterns depicted in the temp graph illustrating temps for the past 420,000 years, it would appear that we (the earth) are due a relapse of falling temperatures which could be the initial stages of an ice age"
Can I recommend that you find the place in the above article where it says "Our current interglacial began around 11,000 years ago. Could we be on the brink of the end of our interglacial?" then continue reading... -
Riccardo at 05:30 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
sbarron2000 #108 "If it's so obvious, Riccardo, why just yesterday did you say..."mathematically (and i'd say logically) the choice of the baseline is totally irrelevant?" It was a joke ... a few weird analogies just to say that the baseline does not matters ... -
Riccardo at 05:26 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
"But you lost the voter right there. 2 degrees 5 degrees, what the heck, who cares." Here jpark has a point. Indeed in our ascientific America or Europe or world or whatever, we see how it's diffucult to explain even the basic arithmetics of trend and anomaly. We have some examples in this discussion where we are dealing with supposedly interested and informed people. And Watts knows this very well, he knows that a picture is much more valuable than a graph and that the only thing that matter is to repeat the same claim obsessively. -
Doug Bostrom at 05:24 AM on 28 January 2010Peer reviewed impacts of global warming
Berényi Péter "scientists are for doing science, not politics. These guys missed this subtle point, so they deserve their fate." Watts et al are making this all about politics. They highlight whatever defects w/IPCC processes they can, to score political points. At the same time they carefully ignore or downplay those results which are unquestionably dependable, all with an eye toward driving public policy. That's political activity. Surely this is obvious? I also think you underestimate the inability of the average person to compartmentalize the message that Watts is sending; it's not just climate scientists who are going to be dragged down, but epidemiologists, materials researchers, others. This is going to be extraordinarily destructive to public policy outcomes springing from a wide array of fields. I honestly do not understand your remarks about renewable energy being "crap" when just a paragraph later you extol the virtues of the fusion power plant available to us just 1 AU distant. With the exception of geothermal power, renewable energy resources have in common that with more or less efficiency they're all powered by the local fusion plant. As you say, it is dependable and free to the extent we can figure out how to exploit it. W/regard to particular technological choices as substitutes for fossil fuels, I'm fairly convinced that we're going to require a widely heterogeneous mix of resources because of the bulky amount of energy required as well as the contextual sensitivity of particular technologies versus deployment scenarios. I'm frankly amazed at how the same group that is in consensus about climate change fragments into a disorganized rabble of constituencies flogging particular technological hobby horses; lack of pragmatism as well as fond wishes for the financial success of various proprietary systems is a serious hindrance to progress. -
jpark at 05:24 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Nope, Ned, def for the science. I am not super familiar with Watts blog or this one here (I like Pielke Jr site tho) and am still learning the basics. There is a lot in the news that makes people like me who are not familiar with the science wonder what it is all about. But I must stop now because I dont think I am adding to the discussion any more - thanks for your patience and the links - will keep reading. -
Ned at 05:21 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
sbarron2000 writes: "I like to see a follow-up study that used more than 40% of the available stations, though." Just curious -- do you expect that the results of such a follow-up study would be different? Because my understanding is that the anomalies are generally well-correlated over long distances (hundreds of km). So you should be able to get a good representation of the US from a relatively small number of stations (see, e.g., John V's analysis). Since the 40% are reasonably well-distributed spatially, my guess is that adding more stations won't have a major impact on these findings. I suspect that's the reason why Watts didn't actually follow through on his plans to provide a comprehensive analysis of the trend data when they reached 75%. If he did such an analysis, my guess is it yielded results similar to those shown here. -
Ned at 05:15 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
jpark writes: "I agree about the andecdotal evidence, I see the argument in Menne et al and appreciate it but - and I apologise for the repetition because it must be boring to read - if that is the best argument for countering Watts paper then Watts 'wins'. It may be ancedotal but it looks more real than all the trends of Menne et al. Might be an illusion, I dont know, that's why I was hoping I would find more here - that's it really." No offense, but it sounds like what you're looking for is entertainment, rather than actual science. That makes sense, since Watts's blog is basically about entertainment. (Or, to be more precise, entertainment with an ideological agenda....) I do hope you'll take some time to browse through the archives here. I think you'll come to agree that the clown show over at WUWT eventually gets old, but that reading and discussing science on a site like this has a lot more to offer. -
sbarron2000 at 05:08 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Thanks for the statistics info, Tom. After doing some research, it seems that if the errors found in the weather station measurements are random, they will be washed out by the averaging, and if they are systematic, they are washed out by using the anomaly chart. I like to see a follow-up study that used more than 40% of the available stations, though. Maybe Watts will do that one himself. -
jpark at 05:03 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
I dont find the Menne et al paper to be about anything real - clever maybe but if this is all about how clever you can be with data from thermometers next to air con units then it is really not at all convincing. I totally agree with your point about anecdotes - I just cant see the point of not answering the basic Watts point which is how can you possibly trust the data. Did you read http://sppiblog.org/news/“horrifying-examples-of-deliberate-tampering-with-the-temperature-data” ? -
angliss at 04:48 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
jpark - so what you're saying is that the actual science doesn't matter, data doesn't matter, mathematical analysis doesn't matter, only anecdotes do. What you're saying is that the observation that jets leave contrails means that the chemtrail conspiracy is real. What you're saying is that anecdotes about vaccines leading to an increased incidence of autism is more important than all the scientific studies that have actual data showing no link. I can find anecdotes for anything, but data is what matters. Watts' surface station white paper was thoroughly demolished by Menne et al, and nothing you or Watts can say will change that. The only way that Watts has a prayer of recovering is if he does the actual data analysis he's refused to do for years and finds a fatal flaw in the Menne paper. -
Jim Eager at 04:44 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
Re causes of the LIA, Ruddiman (2003, 2007, 2008) suggests that a draw down of atmospheric CO2 caused by reforestation in Europe and the Americas in the wake of human population decreases due to pandemics also contributed to lower Northern Hemisphere temps. -
Ian Forrester at 04:18 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
Berényi Péter said:Even with that in mind the stability of the last 8000 years is absolutely exceptional.
That is why it is critical that we stop/slowdown the rapid changes we have introduced into the climate by release of greenhouse gases. Mankind is dependent on a stable climate. -
Berényi Péter at 04:04 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
Let's make it straight. We are not heading into an ice age, we are in one from several million years ago until right now. As long as we have huge permanent ice sheets in the vicinities of both poles, it is an ice age. The extent of ice sheets, mainly around the arctic may vary. There are transient warming episodes called interglacials when the northern ice sheet contracts to Greenland. We are just in such a phase. You may also notice in figure 2 that during the brief interglacials climate is more stable than otherwise. Even with that in mind the stability of the last 8000 years is absolutely exceptional. -
Lupine at 03:40 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
^Don't you understand? The sun is causing Global Warming by cooling and driving us into an Ice Age. Makes perfect sense. -
angliss at 03:30 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
American Thinker also regularly proves that their climate/science writers are dumb as stumps when it comes to actual science. I've lost count of the number of times that they talk about Mars' climate as if it has some bearing on the Earth's climate, especially when they say "Mars is warming, so that explains global warming here on Earth" in the same post as they say "the Earth's cooling trend is driven by the sun." Both statements cannot be true. -
Tom Dayton at 03:30 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
sbarron2000, any error is variation around the mean. The mean is unaffected. Averaging lets those variations cancel each other out--averaging across stations at the same time, and averaging across times (e.g., averaging all the daily measurements to produce a monthly mean, averaging the monthly means to produce a yearly mean). That's what statistics is about. Basic statistics. High school level. Not the least bit debatable. -
Ubique at 03:23 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
Fascinating stuff thank you - but still only one variable in the the overall equation I would suggest. -
sbarron2000 at 03:17 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Tom, Aren't we actually saying "the asphalt instrument reads 55 degrees F (+/- 2.5 degrees C for a type 5 station), and the distant instrument reads 50 degrees F (+/-0.5 degrees C, for a type 2 station)? And "Tuesday the overall air temperature in that local area is two degrees higher than it was Monday. So the asphalt instrument reads 57 degrees (+/- 2.5 degrees C for a type 5 station) degrees and the remote instrument reads 52 degrees (+/-0.5 degrees C, for a type 2 station)? Given that degree of error, can we be certain we can draw meaningful conclusions from the "consistent" 2 degree temperature difference found over those 2 days at these two sites? I'm not sure that repeating this process several hundred times, then averaging the results with similar stations creates any more meaningful info than can be had on day-to-day basis. I have not read all of Menne 2010, so maybe they address this. But so far, no one else has. -
jpark at 03:07 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Not really, Ned but thanks. I agree about the andecdotal evidence, I see the argument in Menne et al and appreciate it but - and I apologise for the repetition because it must be boring to read - if that is the best argument for countering Watts paper then Watts 'wins'. It may be ancedotal but it looks more real than all the trends of Menne et al. Might be an illusion, I dont know, that's why I was hoping I would find more here - that's it really. -
Ned at 02:57 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
jpark writes: "There is too much out there saying the data has been fixed and too little documentation and rebuttal of the charges." You have that exactly backwards. Watts only offers anecdotal evidence (look at this photograph!) and forceful assertions (the data are garbage!) But he refuses to actually do any quantitative evaluation of the trends. The paper discussed in this thread provides a study that was specifically designed to test Watts's claims. As it turns out, those claims are wrong. The impact of individual station siting on the temperature trend is minimal, what impact there is is mostly compensated for by the analytical process ... and insofar as poorly sited stations have a bias, they tend to be too warm in the early years and too cool in more recent years, which means they are underestimating the warming trend. I hope this helps. -
jpark at 02:51 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Tom, true. But you lost the voter right there. 2 degrees 5 degrees, what the heck, who cares. Oh, ok then, I wont bother! (Only playing devils advocate there - not trying to be rude!) -
Tom Dayton at 02:48 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Sorry, my first sentence in my previous comment was supposed to be "It makes no difference to the change across time." (I was writing my two comments in parallel and copy-pasted wrong.) -
Hoskibui at 02:48 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
I get it now - cheers, should have checked the link. I thought the part from 1611-1880 was from another source. -
jpark at 02:47 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
this was good tho' http://www.theage.com.au/opinion/politics/be-alert-but-wary-on-climate-claims-20100126-mw7z.html -
Berényi Péter at 02:47 AM on 28 January 2010Peer reviewed impacts of global warming
doug, scientists are for doing science, not politics. These guys missed this subtle point, so they deserve their fate. Otherwise if carbon dioxide were in fact a problem, all this talk about renewable energy is crap. There is not nearly enough to cover the needs of economy. BTW, according to the principle of cui bono, it must be the nuclear lobby that lurkes in the background. For at the moment nuclear energy is the only viable alternative to burning carbon compounds and it makes no carbon dioxide at all. Hydrocarbon industry comes as a second bet, as coal produces twice as much CO2 than oil or methane for the same energy output. Oherwise energy is NOT a limited resource. We have this huge fusion power plant nearby. At its surface the EM radiation power flux is 63 MW/m^2, total power output is 3.85x10^26 W and it can not even be switched off. It is not availability that restricts usage, but lack of technology. We should work on that (informatics of matter, i.e. molecular nanotech) and forget the rest. Or, if it is really urgent, learn to love nuke. Pour taxpayers money into immediate development of thorium breeder reactors. They do not make plutonium (the stuff used in warheads) and would generate a hundred times less nuclear waste than present day models. Thorium reserves last for thousands of years. RSVP, overpopulation is a problem, but earth is not overpopulated that much. The present state would ceartainly not justify austere measures like genocide, mass sterilization, artificial famines (e.g. by biofuel rush), industry restrictions, compulsory vegetarianism, free euthanasia, abolition of constitutional rights, etc. Raising the educational level of girls worldwide should suffice. The overall fertility of educated women is much lower, independent of culture. It costs (taxpayer's) money, but worth it. Does not curtail freedom, makes informed decision possible. Education restricted to boys does not have the same effect. -
Tom Dayton at 02:46 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
jpark wrote "You say a weather station sitting next to an a/c unit makes no difference - I just find that too hard to swallow." It makes no difference to the anomaly--to the change across time. The instrument on black asphalt might be five degrees hotter than an instrument 50 feet away, but that difference is constant across days. Monday, the asphalt instrument reads 55 degrees F, and the distant instrument reads 50 degrees F. Tuesday the overall air temperature in that local area is two degrees higher than it was Monday. So the asphalt instrument reads 57 degrees and the remote instrument reads 52 degrees. The change across days is 2 degrees regardless of which instrument you use. Both instruments accurately reveal the change in temperature of the ambient air. That consistency of change across time when measured by "nearby" instruments is not an assumption, nor a theoretical prediction. It is an observed fact. Observed over and over again. You personally can observe it by downloading and analyzing the temperature data. -
jpark at 02:45 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Tom, thanks. I do understand the idea of trends - I do get it, the penny is dropping. But is that it? If that is the totality of the AGW argument (eg. who cares how poorly sited the temp station is) then it looks like the idea is in big trouble. There is too much out there saying the data has been fixed and too little documentation and rebuttal of the charges. Sorry - am repeating myself. -
70rn at 02:39 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
@11 If you click on the link for Solanki's data in the reference the set it self starts in 1611. Yeh im not sure where the 1880 figure comes from either. -
Tom Dayton at 02:33 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
jpark and others, The "trend" that is temperature change is change across time. That trend is the "slope" of a graph of temperature on one axis and time on the other axis. By definitions of "trend" and "slope." The trend and therefore the slope will be unaffected by moving the entire plot up or down on the y axis (when the y axis is temperature). Moving the entire plot up or down on the y axis is exactly equivalent, by definition, of adding or subtracting a constant to all the temperatures. In other words, adding or subtracting a constant to all the temperatures does not change the trend of temperature across time. All the above is grade-school math. Not smoke and mirrors. -
Hoskibui at 02:32 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
-Response: -Not sure what you mean - what is the flaw? Maybe a misunderstanding of my behalf - figure 1 shows solar activity from 1611, but Solankis data dates only back to 1880. Never mind, good post. -
jpark at 02:24 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
I have been travelling so had limited time to read and digest but have found the exchange on this page to be especially enlightening - and gosh it appears I am a skeptic, oh dear. sbarron's last point is one I would echo. There is a lot for me to learn but if climate science looks like it is using 'tricks' to make me 'believe' something I will remain skeptical - I need to know that the data/baseline is good so that I can trust the trend it shows. You say a weather station sitting next to an a/c unit makes no difference - I just find that too hard to swallow. And today this: http://sppiblog.org/news/“horrifying-examples-of-deliberate-tampering-with-the-temperature-data” http://scienceandpublicpolicy.org/images/stories/papers/originals/surface_temp.pdf Tho' it is another Watts paper so maybe not welcome. -
barry1487 at 02:02 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
As far as I can tell, the baseline period was chosen because it occupies a period in history that was mostly stable for other, potential contributing climate change factors (solar, NAO, PDO, volcanoes etc etc). I can't vouch for it, but it seems to make sense. IIRC, I have read that it is statistically preferable to choose a stable (no trend/little trend) period as a baseline. -
sbarron2000 at 01:58 AM on 28 January 2010On the reliability of the U.S. Surface Temperature Record
Riccardo, If it’s so obvious, Riccardo, why just yesterday did you say..."mathematically (and i'd say logically) the choice of the baseline is totally irrelevant?" And just to clarify, I never said if the baseline changes, the baseline changes. I said if the baseline changes, then a given year's or decade's anomaly from the baseline will likely also change. And as I already said, if we were talking trend lines, I'd agree that the baseline doesn't matter. But we're not talking trend lines, as Marcus was citing a specific temperature anomaly over the "baseline." That baseline was set at 1961-1990. Which also, unfortunately Riccardo, is not pre-industrial, if that is what your last post is intending to imply. Marcus, You must see the significance between whether temperatures in 2000-2009 increased by +0.515 degrees C or only +0.26 degrees C, right? barry, I bet there are statistical reasons for choosing certain baselines. And in the hands of scientists, for the purposes for which they're intended, those baselines work great. But don't you see how Marcus used the enormity of his "facts" to attempt to put down jparks skepticism? As Marcus later admitted in #105, depending on where you set the baseline, the 2000s temp might have only increased by +0.26 degrees C, and not +0.515 degrees C as he argued. So while the scientists haven't done anything wrong in selecting their baseline, and Marcus correctly cited their data, Marcus didn't really provide the whole story in making his argument. I don't mean to pick on Marcus. His post just happens to be a perfect example of why I'm skeptical. Specific information can be highlighted to make a point, but later we learn that the details tell a different story. Heck, that seems to be the exact same trouble the IPCC is having these days. You can make a persuasive argument using only the best facts that support it, but that doesn't make your position true. And while your intentions may have been sincere when you made your argument, when the rest of the facts come out it makes you look disingenuous. -
Dennis at 00:21 AM on 28 January 2010The upcoming ice age has been postponed indefinitely
Don't neglect the fact that some ice age enthusiast like to assert that back in the 1970's the whole climate science community was all behind the belief that we were headed for an ice age. (Cue for them to pull out a dusty copy of Newsweek.) That assertion was debunked by Peterson, et. al. in Sept. 2008 BAMS "The Myth of the 1970s Global Cooling Consensus."Response: Been there, debunked that. Interestingly, an ice age was predicted in the 1970s is the 8th most popular skeptic argument, narrowly pipping we're heading into an ice age. -
Tony Noerpel at 23:46 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Hi John Nice. WRT comment 3, the columns are not labeled in the referenced table but they are further up the link. The data goes from 1611 to 2004 both in the figure and at Solanke's web site. I wouldn't call this a big flaw but the figure legend says 1880 to 1978. :) Does the data during the overlap align? Thank you TonyResponse: The Solanki TSI reconstruction and the PMOD satellite data do overlap after 1978. They show good correlation but I go with the PMOD satellite data as it's always better to use directly measured data over proxy reconstructions if you've got the option. I go into the construction of this graph some more here... -
chris at 23:25 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Fitz, Apparently the likelihood of the Gulf Stream switching off is not high: W.S. Broecker (1999) What If the Conveyor Were to Shut Down? GSA Today 9, 1-7 http://faculty.washington.edu/wcalvin/teaching/Broecker99.html see also discussion here: http://www.realclimate.org/index.php/archives/2005/05/gulf-stream-slowdown/ ...and if it did shut down, apparently this wouldn't be able to trigger an ice age: T. Kuhlbrodt et al. (2009) An Integrated Assessment of changes in the thermohaline circulation Climatic Change 96, 489-537 http://www.springerlink.com/content/75233057q541716x/?p=a742b208fb45474cb847ee5ac0b1aa37&pi=3 -
Riccardo at 23:12 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
Oh well, we now learn the obvious. If we change the baseline the number changes! I could say I live on the 10th floor of on the first, it's just a change of the baseline. Or I could say that mount Everest is 8000+ m high if I want to impress you, but i could say it's just 1000+ m; it's just a change of baseline again. In the first example the obvious choice of the baseline is ground level, in the second (average) sea level. Guess the obvious choice of the baseline when talking about warming from the pre-industrial era ... they're hiding the rise!!! -
Ned at 23:06 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Arkadiusz Semczyszak writes: But for example, Lindzen has "a different view" about total RF of CO2; see [...] lindzen-choi-model-vs-reality.JPG I wouldn't put much weight on Lindzen & Choi 2009; it has a multitude of serious flaws that have been well documented elsewhere. See here, here, here, and here. Lindzen is one of the very, very few actual climate scientists who doesn't accept the consensus understanding of climate change. The exceptionally poor quality of L&C 2009 ought to tell us something about how weak that contrarian position is. Likewise, the fact that so many self-described "skeptics" were willing to uncritically accept the L&C 2009 paper without a second look is a nice demonstration of how credulous rather than skeptical most of these so-called skeptics are. A genuine skeptic would subject claims on all sides of a question to close examination. In the case of "climate skeptics" however, there's a fascinating combination of extreme, exaggerated skepticism towards mainstream climate science coupled with an utter lack of skepticism towards any paper, no matter how weak, that appears to contradict mainstream climate science. More examples of this phenomenon can be seen in the non-skeptical "skeptic" response to Chylek and to Khilyuk and Chilingar. -
Marcus at 22:59 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
Barry also makes a good point. If I wanted to overstate the extent of the anomaly, I'd pick a 30-year baseline period like 1901-1930, when the average global temperature was 0.23 degrees colder than the 1961-1990 period. As far as I can tell, the baseline period was chosen because it occupies a period in history that was mostly stable for other, potential contributing climate change factors (solar, NAO, PDO, volcanoes etc etc). I can't vouch for it, but it seems to make sense. -
Marcus at 22:54 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
Sbarron, what total rubbish-the anomaly trend doesn't alter at *all*. For example, GISS & HadCru both use the baseline of 1961-1990, & get a warming trend of around +0.163 degrees per decade for the period of 1979-2009. RSS & UAH satellite data, which uses a baseline of 1979-2000, shows a warming trend of around +0.156 degrees per decade over the 1979-2009 period-very little difference in trend irrespective of the absolute values of the anomalies. Also, both sets of data show a general acceleration in the warming trend, with each decade warming by more than the preceding decade-a disturbing trend regardless of your baseline. Be that as it may, when compared to the 1961-1990 baseline, we see the average temperature anomaly for 2000-2009 being +0.515 degrees, when compared to the 1979-2000 average (which, as you yourself admit, includes the warm 1990's period-& which is mostly *after* accelerated global warming is believed to have begun) the average temperature anomaly for 2000-2009 is still +0.26 degrees. So I'm really curious, what *exactly* is the nature of your objection? -
barry1487 at 22:48 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
If you change the baseline each successive decade, then decadal comparisons then become a more complicated exercise to say the same thing. Someone once told me that NSIDC chose their baseline to make later anomalies look bigger! In fact, they've considered switching to a 30-year base period, but it means that all their previous reports will be out of step (not on trend, obviously). Do they then go back and do the laborious task of making values on old web pages etc conform? No, better to keep the base period and save the trouble. sbarron, do you know there are statistical reasons for choosing those baselines for the temp records? They're not arbitrarily selected, and not to derive preferred magnitudes of anomalies (or they might easily have selected a much lower baseline - say 1880 - 1910, or the global temp at the year 1901...). -
Marcus at 22:39 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Arkadiusz Semczyszak-Lindzen can be readily dismissed IMHO. His study into the impacts of the Iris Effect have been found to be largely incorrect, because the Iris Effect lets in more energy than it lets out-as shown by the CERES satellite data. I've little doubt that Lindzen is incorrect on most other factors related to global warming too, as his vision is a little distorted by the views of his....benefactors. Also, American Thinker is hardly a quality source of unbiased reporting. It is Far Right in *all* its viewpoints. -
Fitz at 22:33 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
I remember being told that the Gulf Stream that brings warm waters from the equator to the North eastern Atlantic could effectively be shut off if global warming continues. I can’t remember the exact argument as it was some years ago in a Geochemistry lecture, but I believe that it was something to do with the warm water being too buoyant (due to salinity) to sink at the poles as they cool and drive the ocean circulation current. If this was to happen, would that not cause a drop in temperature across Europe, increasing the Earth's albedo and cause the start of another ice age? I know that this screams of that awful film “The Day After Tomorrow”, but is there any credibility in this happening over a more realistic timescale? -
sbarron2000 at 22:32 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
"Response: Note that the choice of the baseline period (eg - 1960 to 1990) has no bearing whatsoever on the temperature trend. As you say, the trend or "how much warmer" it's getting is what we're interested in when we look at temperature anomaly." Trend lines on an anomaly chart don't show how much warmer its getting, only whether its getting warmer, getting colder, or staying the same. It also shows how fast that is happening by the slope of the trend line. And I agree the slope of the trend line won't chage based on the selection of the baseline period. But the "degrees in C" magnitude of the change for a given period, or how much warmer its getting in degrees, is very much affected by the baseline. Marcus' statement that the 2000s were +0.515 degreee C warmer is only true when the baseline was set in 1961-1990. If you change that baseline, you change the average, which means you'll change how much warmer teh 2000s were by comparison. If you included the warm 1990s, or the even warmer 2000s, in your baseline, the actually increase in degrees C 2000s won't be nearly so high. The selection of the baseline can very mcuh shape the "results," and should give everyone pause when provided with information like that. Lies, damn lies, and statistics... -
Arkadiusz Semczyszak at 22:23 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
"solar activity is estimated between 0.17 W/m2 (Wang 2005) to 0.23 W/m2 (Krivova 2007)." The sun - the climate - is not only a change in TSI. I recommend my comment here: http://www.skepticalscience.com/1500-year-natural-cycle.htm "In contrast, the radiative forcing of CO2 since pre-industrial times is 1.66 W/m2 (IPCC AR4)" But for example, Lindzen has "a different view" about total RF of CO2; see: http://www.americanthinker.com/Attachment%202.PNG; and http://lh4.ggpht.com/.../lindzen-choi-model-vs-reality.JPGResponse: Lindzen is not talking about the radiative forcing of CO2. He's talking about the climate response to radiative forcing. Eg - climate sensitivity. Lindzen believes climate is less sensitive to radiative forcing than is commonly thought. As far as the current topic of ice ages go, the climate response to a cooling sun would be even less according to Lindzen than is conventionally thought.
Coincidentally, the topic of climate sensitivity and the work of Lindzen will be addressed in the next post within a day or two. -
Hoskibui at 22:23 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Excelent work. One minor flaw that needs to be fixed - reference for the first part of figure 1.Response: Not sure what you mean - what is the flaw? -
Philip64 at 22:22 PM on 27 January 2010The IPCC's 2035 prediction about Himalayan glaciers
Doug Bostrom: Thanks for that. I assume the Sunday Times article says more-or-less the same as the Daily Mail article. Where did this IPCC response appear? I would hope in The Sunday Times itself, but given the way that paper is sliding on this issue, I wouldn't be surprised if that was not the case. -
Philip64 at 22:13 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Excellent piece. Many people find the Interglacials graph especially persuasive; which is why it pops up on skeptic blogs again and again. -
sbarron2000 at 22:11 PM on 27 January 2010On the reliability of the U.S. Surface Temperature Record
"Response: Note that the choice of the baseline period (eg - 1960 to 1990) has no bearing whatsoever on the temperature trend. As you say, the trend or "how much warmer" it's getting is what we're interested in when we look at temperature anomaly." I disagree. A trend in this case will be that the temp is going up, going down, or staying the same. That trend will have a slope. And I agree the temp. anomaly chart will show that trend, regardless of the base period, and the slope of the trend line will always be the same. But the magnitude of the temp change on an anomaly chart for any given year, or how much warmer that year was than average, is very much influenced by the baseline period. The 2000s where the warmest decade 'on record.' By including them in the baseline, you would increase the average temp over the entire baseline period, thus reducing the magnitude of the increase in temp in the 2000s "over the average." In doing so, the 1960s temp anomaly will apppear colder, because the baseline will be warmer than it was before the 2000s were included. If your intention is to find the trend line, then I agree the base period won't matter. But if you use the anomaly chart to argue "the 2000s showed an +0.513 C increase over the average, the baseline very much does matter. -
bit_pattern at 21:59 PM on 27 January 2010The upcoming ice age has been postponed indefinitely
Brilliant work as always, John!
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