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Keep those PJs on: a La Niña cannot erase decades of warming

Posted on 8 November 2010 by John Bruno

Former TV weather guy Art Horn has a post up at Pajamas Media about the current La Niña. He mixes some reasonable and accurate observations with several important misconceptions and misstatements about weather, oceanography and climate change.

Mr. Horn correctly points out that we are in the midst of a strong La Niña phase of the El Niño Southern Oscillation (ENSO) cycle. We entered the current La Niña when the last El Niño ended in April/May (or a month or so later based on NOAA's Multivariate ENSO Index). As a result, equatorial Pacific Sea Surface Temperatures (SSTs) are currently about 1.4 C cooler than average.

 

As Art says, the switch from El Niño to La Niña was abrupt, as can be seen in the rapid change from negative to a positive Southern Oscillation Index (SOI):  

Fig 2. The Southern Oscillation Index (as plotted by the Australian Government Bureau of Meteorology above) is based on the measured air pressure difference between Tahiti and Darwin. Sustained positive values are associated with stronger Pacific trade winds and are indicative of La Niña. 

Record high temperatures during La Niña

Art then goes on to make a number of errors in his analysis of the relevance of this La Niña, and ENSO in general, for anthropogenic climate change. Although his wording is a bit vague, he seems to suggest that a La Niña can somehow erase anthropogenic heat accumulation:

"strong La Nina events drop the Earth’s average temperature around one degree Fahrenheit" "The most recent La Nina developed in the spring of 2007, and persisted until the early summer of 2008. The global average temperature fell one degree Fahrenheit in that period of time, equal to all of the warming of the last 100 years!"

Two points of correction:

  1. Global temperatures during La Niña tend to be about 0.1 C cooler than average (not 0.6 C as Art states; just look at the global temperature graph below).
  2. Global warming over the last 100 years was more like 0.8 C (not 0.55 C). 

To state the obvious, the ENSO cycle is a primary driver of inter-annual climate variability, particularly global surface temperatures. I think the source of Art's confusion is that he doesn't understand the difference between instantaneous global temperature averages and longer term temperature trends (which is what climate change is all about).  As I explained above, the observed cooling during a La Niña does not equal the warming over the last century (it doesn't even equal the warming over the last few decades). But that point is largely immaterial since when this La Niña phase ends, the instantaneous average will go back up to where the long term trend (or running average) lies, i.e., the cooling effect is temporary. 

Fig 3. Instrumental record of global average temperatures as compiled by the NASA's Goddard Institute for Space Studiesfrom Global Warming Art

Furthermore, this is all just quibbling about terrestrial surface temperatures, when all the action is in the ocean, which are absorbing >90% of the excess heat being retained by the greenhouse gas blanket (Fig 4). Only about 2% of the excess heat is going into warming the surface air. 

Fig 4. Redrawn by John Cook with data from Murphy et al 2009.

Mr. Horn also states "Many parts of the southern United States had record heat this summer" and "For the last year, the world has been dealing with the warming effects of a strong El Nino." Like the New York Times did in labeling 2010 "an El Niño year", Mr. Horn mistakenly asserts, albeit indirectly, that El Niño has dominated our weather this year. Lets take a look at what the global climate has been doing during the first six months of Art's "super" La Niña. The recent NASA GISS report "2010-How warm was this summer" states: 

• June-July-August 2010 was the 4th warmest in the 131 year GISS analysis [for the northern hemisphere it was the second warmest]

• 2010 was a bit cooler than 2009 mainly because a moderate El Niño in the equatorial Pacific Ocean during late 2009 and early 2010 has been replaced by a moderate La Niña

• 8 of the last 10 summers were warmer than the 1951-1980 mean in the United States and Japan, and 10 of 10 in Europe. So if you are perceptive and old enough, you should be able to notice a trend toward warmer seasons.

• The global seasonal temperature anomaly for March-April-May in 2010 was the warmest in the 131 year GISS temperature data set

Furthermore, coral reefs are bleaching worldwide this year due to the anomalously high ocean surface temperatures.  The result is extensive coral mortality in the Caribbean and SE Asia over the last two months. 

NOAA's Global Climate Analysis for September 2010 states, quite remarkably, that:

"The global average ocean surface temperature for the period January–September was also the second warmest on record, behind 1998"

That is despite the facts that the El Niño that dominated the early months of 2010 was quite mild, the current La Niña is strong and this period of 1998 was warmed by the strongest El Niño of the last 100 years. 

There is generally a 2-3 month lag before land surface temperatures respond to changes in ENSO, so it is reasonable to argue that the last El Niño could be in part responsible for the high global temperatures in May-July 2010. However, as Dr. Simon Donnor points out at Maribu, it is highly unlikely that the record breaking global temperatures of 2010 would have occurred in the absence of greenhouse gas emissions. This is especially true given the weakness of the last El Niño and the abruptness of the switch to a strong La Niña. (See the great discussion of this issue in relation to Moscow's 2010 record high summer temperatures on Open Mind here.) 

No net warming since yesterday

Art Horn: "there has been no net warming or cooling since around 1999. Interestingly, the amount of carbon dioxide in the atmosphere has risen from 369 parts per million to 387 ppm (parts per million) during this time. This amount is above the level of 302 ppm in 1910, when 20th century global temperature started to rise. Despite this significant rise in carbon dioxide since 1999, there has been no “global warming” during this period."

Despite being thoroughly debunked, the "It hasn't warmed since 1998" meme is still alive and well in the denial-o-sphere. This argument is flawed in at least four ways: (1) it isn't true, (2) it is a great example of climate cherry picking, (3) it ignores the well-known role of ENSO in driving year-to-year climate variability and (4) it is a classic straw man fallacy in that it seeks to counter an argument that nobody is making: the (false) expectation of progressive annual warming, i.e., even if true, it wouldn't be relevant to the argument at hand.  

Tomorrow we will see the sun with a chance of rain

Mr. Horn closes with a prediction: "Right now El Nino’s colder sister is on the fast track to generate more temperature extremes and a very cold winter in some parts of the world."  At least about this, he is correct (but only partially, e.g., much of the US is actually typically warmer than usual during La Niña, Fig. 5). There will surely be record highs and lows over the next six months and a very cold winter somewhere on earth, possibly due to La Niña.  

In fact, I'll up the ante and predict that this will be the case for the next 100 years. Anthropogenic climate change does not mean (or predict) progressive, homogenous warming everywhere. Some places are going have cold winters even a century from now. Cold records will continue to be broken (although with reduced frequency). There will likely be regions that cool, especially if ocean currents are altered, and we could see cool decades.  Yet none of that will negate the warming effect of greenhouse gases on the atmosphere and oceans. So keep your PJs on Mr. Horn. A La Niña, no matter how strong, is just a natural cycle that is riding atop of a warming planet, and it certainly cannot erase decades of heat accumulation.  

 

Fig. 5. Seasonal mean temperature trends for the United States during Strong La Niñas.

PS. Take a look at the comments to Art's piece and try to count the number of skeptic arguments. A quick scan revealed "It's freaking cold!" "It's cooling" "Al Gore got it wrong" "It's methane" "It isn't warming" "Warming ended" "It's the sun" "The Medieval warm period and those vikings" and "Ice age predicted in the 70s"

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Comments 51 to 76 out of 76:

  1. Re: John Bruno. I can't do it now from my cell but will later. Unless someone (like Ned, for example - heh!) beats me to it.
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  2. John Bruno writes: Anybody with extra time on their hands want to take on comments 44 and 45 above? - JB Well, I don't really have time on my hands, but I'll take a shot anyway. As quoted at the top of this thread, Art Horn originally wrote: "strong La Nina events drop the Earth’s average temperature around [0.6 C]" and also "The most recent La Nina developed in the spring of 2007, and persisted until the early summer of 2008. The global average temperature fell [0.6 C] in that period of time, equal to all of the warming of the last 100 years!" The first statement is true if you look at short time scales. If you want to look at sub-annual-scale variation in global temperature, then yes, the ENSO cycle can cause global temperatures to fluctuate by 0.6 C for short periods of time. The problem is when you compare that to a different form of variation in climate (e.g., AGW) that occurs over much longer time scales ... as Mr Horn does in the second quote cited above. It's completely inappropriate to compare the short-term variation from ENSO to the long-term variation from AGW ... because over the long term, all the short-term variations will get averaged out. As John Bruno notes in the post at the top of this thread, when you look at the annual data, ENSO only has about an 0.1 C effect on temperatures. If you look at longer scales (e.g., decadal averages) it's negligible. The statement that the temporary, short-term drop in temperatures from La Nina is "equal to all of the warming of the last 100 years" is deeply misleading. The drop in temperature from day to night, or from summer to winter, is far greater than "all the warming of the last 100 years" ... but we recognize that the diurnal cycle and the seasons are short-term, cyclical phenomena, and that the large amplitude of the temperature change will be insignificant when averaged out over long periods. HumanityRules, does this clarify things at all?
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  3. Now, here's something that's just plain wrong. HumanityRules wrote: So those descriptions from the NASA GISS report "2010-How warm was this summer" should all have explanations of how El Nini is influencing them. Obviously they don't because any description of natural variability would confuse the message. You obviously didn't bother actually reading the GISS report that you cite, because it's absolutely chock-full of discussions of the ENSO cycle and its effects on short-term fluctuations in global temperature. I'm not going to quote any specific sentence from the report, because the whole thing is full of references to El Nino and natural climate variability. Seriously, I'm really bothered by HumanityRules's sneering dismissal of the GISS report. Having actually read the report, I think it's a great model of how to talk about the fact that any given year's spatial-temporal pattern of temperatures and precipitation is the result of interactions between short-term natural variability and the long-term warming trend from AGW. Please, HumanityRules, either read the GISS report if you haven't actually done so, or explain why you think that the more than a dozen references to ENSO in a sixteen-paragraph press release are somehow insufficient.
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  4. #44: "I'm interested in what sort of variability the ENSO sytem introduces into that metric, " Every time one of these ENSO flaps comes up, I'm struck by the same question: How can anyone actually believe that an oscillation of surface temperature and pressure -- essentially a dyamic system's response to a perturbation from equilibrium -- can be a driver of long-term climate variation? The only clear long-term variation in the MEI ENSO graph shown by John B above is the change-over from mostly negative to more frequent positive in the mid-70s. Run the cumulative of this index and you see a strong relative minimum in 1976. After that point, it's steadily upwards. The five negative dips since then (including the current one) do not erase the long term trend. Here's an older version of this graph from an old Bob Tisdale blog:
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  5. Sphaerica at 04:33 AM on 10 November, 2010
    I also believe that I've read that the conversion factor is roughly 1.2, so +0.14C/decade troposphere equates to a surface change of +0.168C (pretty close to NASA GISS at +0.166C).
    The factor 1.2 is the ratio of the global TLT trend/surface trend (~30 years). It can't be used to scale surface anomalies to TLT anomalies and vise versa. Sphaerica at 04:59 AM on 10 November, 2010
    Perhaps the difference lies in what the AMSU near surface data actually represents. I'm not well informed on that particular detail.
    The near surface layer gets a lot of interference from water vapor, precipitation and ice on land and in the clouds. It's really not the best choice for temperature sounding. Albatross at 05:18 AM on 10 November, 2010
    The RSS page has a nice figure showing how the weighting works for different channels,I am not aware of such a figure for UAH.
    Try to dig up any of the papers by Spencer and Christy. They show the weighting functions. Sphaerica at 07:59 AM on 10 November, 2010
    My factor of 1.54 (or 1.55) is used to convert the LT temp into a corresponding surface temp, e.g. Ts = (1.54 * Tlt) - 134.16 for 30 day smoothing, and it does so with a fairly high correlation.
    Your high R2 values may be an artifact of the smoothing process.
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  6. "How can anyone actually believe that an oscillation of surface temperature and pressure -- essentially a dyamic system's response to a perturbation from equilibrium -- can be a driver of long-term climate variation?" Because a lot of people who wont/cant do the arithmetic believe its all a natural cycle and temps will go down again. If you switch off from any data that contradicts this view (its all UHI, black carbon, XBT errors, satellite calibration, poorly located tide guages etc) then every La Nina looks like confirmation of your expectation - and you only look for confirmation of your beliefs, right? What the hell are they teaching in science in schools?
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  7. #56: "What the hell are they teaching in science in schools?" Now, now, scadden, every school must have its top-of-the-class and those who major in 'Rocks for Jocks' or 'Science for Poets' or even 'Computers for Poets'. The good news is that these bottom-dwellers can find full employment -- as yes-men to the Watt$ of the world.
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  8. Hey now, muon--why single out the humanities? High school "poets" may not be the most critical of critters, but of the vocal "skeptics," I'd wager most are engineers and business types--Ayn Rand-reading folk who understand enough science to make them confidently dangerous.
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  9. Well to be honest, I have actually had some input into science education. My beef is that it is too easily (and usually) taught as natural history. Its scientists that learn the observe-model-predict-observe cycle and disciplines to try and avoid fooling yourself. I'd like that to be taught early, to everyone. Learn to use scientific method as BS detector (Sagan's "candle in a demon-haunted world") - but this is something of a digression from this thread...
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  10. Ned at 03:31 AM, you are correct in making the comparison between the ENSO cycles and the drop in temperature from day to night, or from summer to winter and the recognition that the diurnal cycle and the seasons are short-term cyclical phenomena, because they are all effects, effects that are recognisable and measurable. However the big difference is that whilst we all know and understand the cause of the night/day cycle, and the seasonal cycle, this discussion hasn't addressed the cause, the real drivers of the El-Nino/La Nina cycle, and until that has been done, none of the questions raised have been answered.
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  11. ESNO is dynamical coupled ocean-atmosphere phenomena and what you mean by "cause" isnt a straightforward question. You are aware that "ESNO-like" features emerge in GCMs? The tough question is "how will ESNO change as the world warms?".
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  12. 53.Ned Ned thanks for the heads up on the other thread, I don't read this website as religiously as I used to which means I don't bother so much to follow up on comments. You were right that I didn't bother reading the GISS article, I've become too cynical about what they put out, I guess I was making the comment on the strength of the GISS quotes John used in his article. But prompted by you I did read it. Unlike you I will quote the GISS article in all the places were they make direct reference to how ENSO has an affect on short term temperature trends.(sorry for the length) "2010 was a bit cooler than 2009 mainly because a moderate El Niño" "The low latitude temperature anomaly was less than in 1998, as the recent El Niño was much weaker than the one in 1998." "Regardless of how long the current La Niña extends, the next two or three seasonal-mean global and low latitude temperature anomalies are likely to be cooler" "The maps compare January-August temperature anomalies for 2010, 2005 (the warmest year in the GISS analysis), and 1998 (one of the warmest years in the GISS analysis, the temperature being boosted by the "El Niño of the century"). 2010 is clearly the warmest of these years for the first eight months." "However, the 4th section of Figure 4 shows that the monthly anomalies in 2010 have declined steadily over the past five months as the Pacific Ocean moved into the La Niña phase." "Given the dominant effect of El Niño-La Niña on short-term temperature change and the usual lag of a few months between the Nino index and its effect on global temperature, it is unlikely that 2011 will reach a new global record temperature." There are other reference to ENSO but I don't think they link them to specific descriptions of particular short term trends. Notice anything? Well it strikes me that most (if not all) of these comments are focused on explaining away cooler conditions in 2010 (2011??) by ENSO. The one that comes closest to talking about warming is misleading. The long one that starts "The warms compare...." acknowledges that an El Nino boosted the temperature in 1998, what it fails to mention is that the 2010 temperature was boosted by El Nino in a similar way. How could they make such an admission? I concede that when GISS have to explain a cooling phenomenon they are happy to invoke ENSO as an explanation. My problem really is when they come to describe warm or warming periods, such as the summer of 2010 they neglect to adequately assign any of that warming to the prevailing ENSO condition. I'll have a go at it myself. /Fig4 shows that while ENSO peaked in Jan2009/Dec2010 global temperatures continued to rise (due to the lag) until March 2010. Although temperatures have fallen since they have remained sufficiently high to record the 4th warmest summer on record./ If you want to add that this is all on the back of a multicentury warming trend you can do but it doesn't take away from the fact that when it comes to describing warm periods GISS suddenly forgets to mention ENSO or any other natural variability. I think that is because they are agenda driven. Fleshed out a bit more but I don't think too far off what I was trying to get at in the earlier post. I don't think GISS don't mention ENSO, I just think they use it selectively. If we get headlines around 2010 being one of the hottest years on record I feel certain they won't be attributing any of that heat to the lingering affect of the 2009/2010 El Nino because they certainly aren't in the present document. Let me know if you think I'm off the mark here. (BTW I'm a man: old, white, male, Western, bigot, heavily invested in oil stocks as if you didn't already know [sarc off])
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  13. That last comment was extremely long winded, i'll summarize it. This NCAR page tabulates the ENSO index. Look at 1997/998 and 2009/2010. While the magnitude of the peaks are different the timing is pretty similar. If the GISS document can say that the 1998 temperature was boosted by El Nino why can't it acknowledge that 2010 was also boosted. Instead it tries to focus on the cooling aspects of the developing La Nina. That is bias because it doesn't wish to assign any of the anomoly to natural variation. Almost like an anti-Art Horn it throws in a couple of out-of-the-blue sentances about CO2 to show it's real intent. If you can accept that Art is agenda driven I don't understand why you can't see it in GISS.
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  14. HR, I think your original remarks about the GISS report were way off base, and I don't think your subsequent effort to retroactively salvage them is particularly justifiable. They wrote that at the end of a very hot summer which saw both the record-breaking 12-month high temperature and a series of high-publicity stories about the heat wave in Russia, etc. If GISS operated the way that many "skeptics" imagine, they could have easily issued a summary that did exactly what you initially assumed it did -- ascribe everything to AGW and not even mention the role of natural variability. Instead, they provided a summary in more or less neutral terms that discusses natural variability at very great length. IMHO the fact that their efforts were apparently not enough for you says much more about your biases than theirs. (Though I obviously am coming from a different point of view; it's possible that their summary seems more reasonable to me because I'm predisposed to agree with them.) HumanityRules continues: If the GISS document can say that the 1998 temperature was boosted by El Nino why can't it acknowledge that 2010 was also boosted. Instead it tries to focus on the cooling aspects of the developing La Nina. They point out correctly that 2010 was influenced by a moderate El Nino that then transitioned fairly rapidly to a La Nina. In contrast, 1997-1998 had an El Nino that was either the largest on record, or second largest (after 1983, depending on which index you follow). Look at the data in the NCAR paper you cited. This past year's ONI (index based on the Nino 3.4 region) peaked at 1.8, and was above 1.5 for a grand total of two months. In contrast, for 1997-1998 it peaked at 2.5 (the highest value in the 60-year record), and it was above 1.5 for eight months, not two. If you believe that El Nino has a significant impact on temperatures, then why can't you accept that a monster El Nino (like 1998) would have a much larger impact on temperatures than the comparatively modest El Nino of 2010? So, to me, it frankly looks like you're being rather unreasonable. GISS talked about El Nino appropriately, and appropriately noted that the most likely reason why 2010 may not break the all-time calendar year record is because the El Nino was relatively modest in magnitude and rapidly transitioned to La Nina. Seriously, how much more can you ask? It seems like you wouldn't be satisfied unless GISS came out and ascribed the entirety of 2010's warmth to natural cycles. Or perhaps you want them to pretend that the 2010 El Nino was as large as the 1998 one, even though it obviously wasn't?
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  15. And why look only at MEI? Since the AMO was in the record highs in the beginning of the year. Combining the effect of these two we have anomalously warm year. @Ned: Well yes, there is a warming trend in the last 15 years. And that is just because nearly all of the warming in the last 30 years happened in a step in the end of 90's. Actually the step would have occurred in the end of 70's if El Chinchon and Mt Pinatubo didnt offset the warming followed from a huge stepwise warming induced by the PDO. And AMO also made a shift back then. If you just detrend HadCRUT since 1900 and compare it to PDO+AMO you will see a very close correlation. Most of the warming in the last 30 years is caused by those (around 60% and 40% might be anthropogenic) so actually there is no recent "acceleration", it is just 30-year weather phenomenoms. And we skeptics are being accused about mixing weather to climate, how ironic is that? Just look at DelSole et al (a recent study) for example, or Thompson et al. Ocean oscillations explain quite a bit from the 20th century warming (and cooling).
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  16. If you just detrend HadCRUT since 1900 and compare it to PDO+AMO you will see a very close correlation. Right, if you remove the long-term warming trend from CO2, you can then do a pretty good job of predicting the residuals based on a bunch of different oscillations. So?
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  17. This could get very boring Ned but I re-read the GISS document and I still could not find any statement where they assign any of the warm anomaly in 2010 to the 2009/2010 EL Nino. As I said they are very quick to assign the late year cooling and possible cooler conditions next year to the developing La Nina. Please Ned quote the sentance where you think they do that, I can't find your bolded sentance in the doc. Ned I get that the 1997/1998 El Nino was stronger than the 2009/2010. I get that the impact in 1998 was greater than 2010, I'm not arguing the opposite. That doesn't take away from the fact that the record 2010 temperature are still in part due to the 2009/2010 El Nino. I still believe GISS don't acknowledge that overtly. I just have to take up your description of 2009/2010 El Nino as modest. Modest definition - "limited in extent" The NCAR data seems to show 18-19 El Nino events since 1950. The 2009/2010 El Nino is joint 4th on the basis of peak number. Modest seems an inaccurate definition for the 2009/2010 El Nino. Above average would be better. You see even you are trying to undervalue the influence of the El Nino on 2010's temperature with your choice of words. Ned I agree with you that to some extent this is a perception point. I will admit I'm super critical of things coming out of GISS, I hope though that always remains within the realms of reality. But this is important because we are often arguing on this website in the way the media and others mis-represent the science. I think the take away messages journistist will get from this document is 2010 is warm and 2011-2012 will be cooler because of La Nina, that is an incomplete story. I think you, me and GISS all know that the warm temperature of 2010 where influenced by the 2009/2010 El Nino, the question is why they didn't overtly state that, please provide the quote where you think they do.
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  18. I thought I'd try see if I could find how the press were reporting this document. I couldn't find anything in the MSM but here's what I could find in some science news sites and others. EurekaAlert ScienceDaily PHYSORG IBT WeatherOnline eScienceNews All of them report the late 2010 cooling to La Nina, none of them assign any of the 2010 warmth to El Nino. Are you happy with this situation Ned?
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  19. > humanityrules > here's the mean monthly global temperature. No it's not. That's the temperature _anomaly_ chart. You do know the difference? Why don't you try again.
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  20. #65: "because nearly all of the warming in the last 30 years happened in a step in the end of 90's." OK, so here is a graph of HADCRuT global from the last 30 years. That positive trend of ~0.16C per decade must be what you mean when you say 'a step'. "Actually the step would have occurred in the end of 70's if El Chinchon and Mt Pinatubo didnt offset the warming followed from a huge stepwise warming induced by the PDO" So we'll go back to the beginning of the 70s: Pinatubo's 'offset' are those low spikes in the early 90s. Short duration. Transients. Here today, gone tomorrow (as opposed to that same positive trend). How Pinatubo 'offset' the warming supposedly 'caused' by a decades-long oscillation is beyond me. A google search of 'correlation pdo amo detrend warming' immediately shows watt the source of this illogic is. But then its easier to repeat than to think; do I hear a chorus of 'four legs good, two legs bad' coming from that direction?
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  21. Humanity Rules, The entire GISS statement says that short term temperatures are dependant on ENSO. "Figure 3 has graphs of the global and low latitude seasonal temperature anomalies. The low latitude anomalies are strongly dependent on the El Nino-La Nina cycle of equatorial Pacific Ocean temperature anomalies, as shown by the Nino 3.4 SST2. Global temperature anomalies tend to reflect Nino variability, with, on average, a lag of about three months." El Nino years set high records and La Nina years are a little cooler. 1998 set an especially high record because it was such a strong El Nino. The next El Nino as strong as 1998 will be much higher than 1998 was. 2010 started off record setting warm, even though it was a modest El Nino. It is now near record warm even though there is a La Nina, a cooling trend. They predict 2011 will not set a record, due to the cooling La Nina, but it is still likely to be warmer than any previous La Nina year in the record. They predict that the next El Nino year will set a new high record. What more about El Nino do you want them to say???
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  22. 69.hank mean monthly global temperature anomaly I enjoy your attention to detail but it changes nothing.
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  23. 71.michael sweet I think it's clear what I want them to say. Some of the 2010 warmth is from the 2009/2010 El Nino. It's not clearly stated and for that reason it's not picked up by the press that's reporting it. Again Modest? 4/19 largest El Nino since 1950. You too want to underplay the role of the 2009/2010 El Nino in the temperature record? Please explain how being in the top 25% of strongest El Nino since 1950 justifies the description modest? It's clear to me they go to great detail to explain how La Nina will influence the later months of 2010 and into 2011 but have no detail on how the El Nino influenced the 1st half of 2010. As you and others have said this is a detailed description of ENSO's role in short term temperature trends, I'm not questioning that. It is also a description of 2010's temp. Given these facts how can they omit such an obvious detail as the early 2010 temperature was influenced by the 2009/2010 El Nino? This is important because it influences the way it's reported to the public. Please Michael/Ned specifically deal with the lack of explicit attribution of the early 2010 warmth to the 2009/2010 ENSO and the impact of how it affects reporting etc because I'm just repeating myself here.
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  24. Interesting item on the BBC website today : This year is heading to be the hottest or second hottest on record, according to the Met Office. But I imagine the so-called skeptics in the UK will be more fascinated with the cold, snowy weather some parts are experiencing here at the moment. The earliest and most widespread snow showers in, um, 17 years...
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  25. JMurphy, I know, funny how that works. The AO has flipped strongly negative again-- similar to what happened last winter. And if the findings from a recent paper are correct, they should expect more of the same in future winters. From ScienceDaily: "The overall warming of Earth's northern half could result in cold winters, new research shows. The shrinking of sea-ice in the eastern Arctic causes some regional heating of the lower levels of air -- which may lead to strong anomalies in atmospheric airstreams, triggering an overall cooling of the northern continents, according to a study recently published in the Journal of Geophysical Research." At the same time we may be experiencing one of the strongest La Ninas since 1975/1976. According to GISS the mean global SAT anomaly in 1975 was -0.16 C. I could be wrong, but I reckon that the global SAT anomaly for 2011 is going to be closer to +0.40 C. I wonder what the difference is between then and now? ;)
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  26. Correction to #75, Global SAT anomaly was -0.16 C (NASA GISTEMP) in 1976, not 1975.
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