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Yes, global warming has continued since 1998

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"Yes, global warming has continued since 1998"

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Physicist John Cook of Skeptical Science has a good post debunking the global cooling myth, “3 levels of cherry picking in a single argument,” reprinted below.

To properly understand what’s happening to our climate, you have to consider the full body of evidence. Most arguments that support climate skepticism have one thing in common — they neglect the full body of evidence and cherry pick just the select pieces of data that support a particular point of view. There is one argument that is so misleading — it requires 3 separate levels of cherry picking. This argument is “global warming stopped in 1998“. Let’s look at the 3 ways it cherry picks the data:

Cherry Pick #1: Select one particular temperature record

This argument is based on a temperature record from the Hadley Centre in the UK, often referred to as HadCRUT (Hadley Climatic Research Unit Temperature). This dataset shows unusually warm temperatures, leading to 1998 being the hottest year in the HadCRUT record. These unusually warm conditions were due to the strongest El Ni±o on record occurring at the time (more on this later).


Figure 1: 12 month average of global temperature anomaly from the Hadley Centre (HadCRUT).

The important point to realise is that the HadCRUT record is not a truly global temperature record. Their record doesn’t include many regions, some of which happen to be the regions where the fastest warming is occurring. An analysis by the European Centre for Medium-Range Weather Forecasts (ECMWF) calculated global temperature, utilising a range of sources including surface temperature measurements, satellites, radiosondes, ships and buoys. They found recent warming has been higher than that shown by HadCRUT as the HadCRUT record misses out on the parts of the world of greatest warming.


Figure 2: Increase in mean near-surface temperature (°C) from (1989-98) to (1999-2008). Top figure shows HadCRUT sampling regions, lower figure shows ECMWF analysis (ECMWF 2009).

This is confirmed by NASA GISS who found a major contributor to recent warming is extreme Arctic warming (Hansen 2006). As there are few meterological stations in the Arctic, NASA extrapolated temperature anomalies from the nearest measurement stations. They found the estimated strong Arctic warmth was consistent with infrared satellite measurements and record low sea ice concentrations. According to the NASA GISS global temperature record, the hottest year on record is 2005. Of course, nature isn’t bound by calendar years. The actual hottest 12 months on record are from June 2009 to May 2010.

NASA GISS global temperature - hottest 12 months on record June 2009 to May 2010
Figure 3: 12 month average of global temperature anomaly from NASA GISS.

Cherry Pick #2: ignore what’s happening to the rest of the climate

Even NASA’s global temperature record doesn’t give you the full picture. The surface temperature record tells us about air temperature at the Earth’s surface. However, this is only a small part of global warming. Because of increased greenhouse gases, the planet is building up heat. More energy is coming in than going out. Did this energy imbalance stop in 1998? To determine this, one study measured the Earth’s total heat content since 1950. The authors used measurements of ocean heat content down to 3000 metres depth. The amount of heat in the atmosphere was calculated using the surface temperature record and the heat capacity of the lower atmosphere. Warming land and the energy required to melt ice were also included.


Figure 4: Total Earth Heat Content from 1950 to 2003 (Murphy 2009).

What they find is the planet has clearly continued to build up heat past 1998. Global warming has not stopped. It also shows that most of global warming is going into the oceans. This is because the heat capacity of the land and atmosphere is small compared to the ocean. This leads us to our third cherry pick.

JR:  First,  I want to add another chart from a Skeptical Science post, “How we know global warming is happening, Part 2.”  The JGR article, “Global hydrographic variability patterns during 2003-2008” (subs. req’d, draft here) details an analysis of “monthly gridded global temperature and salinity fields from the near-surface layer down to 2000 m depth based on Argo measurements.”  Background on Argo here.   Their findings are summed up in this figure, which show warming continues unabated even through 2008:

Figure [2]: Time series of global mean heat storage (0-2000 m), measured in 108 Jm-2.

Cherry Pick #3: Comparing single years rather than statistical trends

The ocean holds significantly more heat than the atmosphere. Consequently, relatively small exchanges of heat between the atmosphere and ocean can cause large changes in surface temperature. In 1998, we experienced the strongest El Ni±o on record. This moved massive amounts of heat from the Pacific Ocean into the atmosphere, leading to an abnormally warm year. Conversely, 2007 saw the strongest La Ni±a conditions in over 20 years which had a cooling effect on global temperatures. In 2010, the Pacific transitioned back to El Nino conditions although not as strong as in 1998. Nevertheless, this resulted in the warmest 12 months on record from June 2009 to May 2010.

This internal variation where heat shuffles around our climate is the main reason why surface temperature is such a noisy signal. With so much internal variability, it can be misleading to make conclusions about climate trends merely by comparing one point of a noisy signal (eg – 1998) to other years. This is why scientists employ statistical methods to discern long-term trends – this is a way of including all the data rather than a few cherry picked years. A common method to remove short-term variations, revealing any underlying trend, is to plot a moving average.

Figure 5 shows the 11 year moving average – the average temperature anomaly calculated over the year itself and five years either side. Three temperature records are examined: the Hadley Centre at the University of East Anglia (HadCRUT3), a branch of NASA called the Goddard Institute of Space Studies (NASA GISS) and the National Climatic Data Center which is part of the US government’s National Oceanographic and Atmospheric Administration (NCDC). For all three records, the moving average shows no sign that the warming trend has reversed.


Figure 5: Yearly global temperature anomalies, together with 11-year moving averages (solid lines). Blue circles from the Hadley Centre. Red diamonds from NASA GISS. Green squares from NOAA NCDC. NASA GISS and NOAA NCDC are offset in vertical direction by increments of 0.5°C for visual clarity (Fawcett & Jones 2008).

– John Cook

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20 Responses to Yes, global warming has continued since 1998

  1. fj2 says:

    Yes this is good.

    How would a cognitive behavioral therapist have a discussion with a climate change denier about his or her unreal thoughts?

    The discussion would likely be much more simplified and include other things.

  2. caerbannog says:

    Phase 1: Use the CRU’s temperature record to argue that the Earth has been cooling since 1998.

    Phase 2: Hack the CRU’s email server and use out-of-context email excerpts to accuse the CRU of fabricating a warming trend.

    Phase 3: Profit!

  3. Mike says:

    Of course the people out there like S.G. who do cherry picking will read this as a how to guide. They will also look for new ways to distort the record. Most people don’t have the time or knowledge to sort out each new example. That is why it is import to discredit people like S.G. They are not just mistaken – they are trying to deceive the public. Whether their motive is profit based or, more likely, they just have a twisted ego, I can’t say. But those with money on the line certainly promote them.

  4. mike roddy says:

    An old friend and college roommate, who has a PhD in experimental nuclear physics, just told me that deniers and Fox News should be held accountable for public endangerment, and temporarily shut down. This friend is not at all disposed to make radical statements, but formed this opinion based on the facts.

    Maybe a counterattack on deniers should go beyond the exercise of continuing to prove that they are lying. Much of the public remains convinced otherwise, since they get their information from goofy blogs and right wing media companies. This commercially motivated distortion of key information needs to be addressed.

    Scientific organizations may be a good place to start, since their charge is wide ranging. There would be fireworks and vicious counterattacks. Fine. Sometimes the truth and serving the public results from these investigations. After all, the scientific organizations investigated “Climategate” and the broken hockey stick, with clear and well documented evidence. Let’s see if the deniers can stand it when the microscope points in their direction.

  5. Nick Palmer says:

    “Most arguments that support climate skepticism have one thing in common — they neglect the full body of evidence and cherry pick just the select pieces of data that support a particular point of view.”

    And each individual sceptic argument can be shown to be mostly inaccurate or wrong. This does not stop some – they just move on to the next “argument”, unscathed by the last one being destroyed.

    Others seem to recover, whereby after their argument has been publicly destroyed, after an interval, they will represent it to their hungry followers without seemingly remembering what happened. What I really, really want to know is this. Are these people mad or bad? They certainly are dangerous. Inside their heads, do they know they are serially lying or are they just serially stupid – is it incompetence or dishonesty?

    On the face of it, many of them seem to be educated – they are often extremely articulate and persuasive (certainly more articulate and skilled in persuasion than many or most climate scientists and commenters…). It seems hard to believe these types are stupid, or completely incapable of assimilating argument, analysing it and drawing rational conclusions from it.

    Does anyone know? Have any of the professional denialists ever been caught out on tape or film or in documentary evidence admitting that they don’t understand the science, are deliberately presenting a deceptive case or that they are simply making stuff up?

  6. Berbalang says:

    Nick @ 5:

    I won’t go into how I know this on this forum, but in answer to some of your questions, many of the professional deniers do know they are lying and are aware of the death and destruction their actions will cause. They gloat over this. They also gloat over the “useful idiots” who deny Global Warming for free and do their work for them.

    There is a rather informative book on-line called “The Authoritarians” which gives a very accurate description of the social interaction between the professional deniers and amateur deniers.

    One question that does occur to me is whether of not the people who hire the deniers realize what they are dealing with.

  7. Bob Wallace says:

    “I won’t go into how I know this on this forum, but in answer to some of your questions, many of the professional deniers do know they are lying and are aware of the death and destruction their actions will cause.”

    If you truly know this then it seems to me that you have moral obligation to make that information public.

  8. djrabbit says:

    Nick @ 5:

    The professional deniers (or as I prefer, “paid deniers” or even “paid liars”) know exactly what they’re doing, which is PR disguised as science. Read Merchants of Doubt, Climate Change Cover-Up, or Doubt Is Our Product (all readable, popular accounts) for the evidence. For example, there are a couple of (leaked) carbon-industry documents that describe the exact strategy that the paid deniers appear to be employing.

    Of course, the paid deniers do not admit this publicly. And at times they do at (implicitly) claim ignorance, since that is less damaging than admitting willful deception (eg, by expressing certainty in unsupported scientific claims while emphasizing uncertainty in well-supported findings; by repeating long-discredited arguments without admitting or attempting to countering the contra-evidence; by ignoring scientific standards and conventions re: peer-review, cherry picking, and the rest).

    But like the proverbial poker player, who makes his fortune by misleading and mis-directing his opponents, they do have tells. Cherry picking of the sort described above is a good example. Other tells include, arguably, making un-sourced citations (so they can’t be verified), and misrepresenting or misquoting the work of other scientists (as an early, infamous George C. Marshall repot did in modifying Hansen’s graphs without disclosure).

  9. Leif says:

    djrabbit, @ 8: I know it and you know it, we all know it. The question I am left with is that since we can be sure that the Government and Obama knows it, how come that the “paid liars” are not called on it. I can only assume that there is approval for their actions. That assumption does not sit well with me. It implies that we are being played as suckers. Or. The Corporations and Capitalism have complete control of BOTH GOBP and Democrat branches of Government. Perhaps there is another explanation that I am missing and if so I would sure like to know it. I do not like the future that I see if either of those options are true.

  10. Eadsel Smith says:

    #378,468 in Books (See Top 100 in Books)
    Straight Up is going down.
    Looks like the hocky stick is breaking downward also.

  11. “Eadsel Smith” demonstrating once again that any activity which might — by some reckless stretch of the imagination — ever be mistaken as evidence of logically valid thought is simply not ever going to be produced by him.

    Let’s begin with the argumentum ad populum fallacy that comprises the first part of his kerygmatic declaration. Facts and truth are not measured by popularity, but by reality. Any further observations about the quality of “intelligence” that would stoop to such a sorry excuse for reasoning could only be interpreted as a personal attack, regardless of how accurate or materially relevant such observations might be.

    The last part is so manifestly vapid that it has never been considered worthy of even naming. Despite the overwhelming evidence to the contrary, the only thing our current troll can imagine doing is spewing nonsense that has been refuted times without count.

  12. Chris Brett says:

    Given that the Amazon top 25 includes 4 self help books and that the top 100 doesn’t contain a single “classic”, i shouldn’t lay too much stock in the rankings. To know an increasing number of people out there are reading your words and are prepared to take action should be enough.

  13. sailrick says:

    Eadsel Smith

    If you want to discuss books on climate change, pro and con, here is somed useful information.

    If you peruse the book shelves at your local Barnes and Noble, you will notice at least as many, if not more, books by climate change skeptics, as mainstream climate science books. There is a reason for this. The same “think tanks” who are spreading the disinformation for the fossil fuel industry, are funding most of these books. They promote 78% of skeptical books on climate change and 90% of skeptic books on the environment in general. This has resulted in at least 64 climate change skeptic books.

    Who are these think tanks? Here are some of them.

    These 32 organizations have all been involved in the tobacco industry’s campaign to deny the science showing the dangers of tobacco.
    They are all now involved in the campaign to deny the science of climate change.

    1. Acton Institute
    2. American Legislative Exchange Council (ALEC)
    3. Alexis de Tocquerville Institute
    4. American Enterprise Institute (AEI)
    5. Americans for Prosperity
    6. Atlas Economic Research Foundation
    7. Burson-Marsteller (PR firm)
    8. Citizens Against Government Waste (CAGW)
    9. Cato Institute
    10. Competitive Enterprise Institute (CEI)
    11. Consumer Alert
    12. DCI Group (PR firm)
    13. European Science and Environment Forum
    14. Fraser Institute
    15. Frontiers of Freedom
    16. George C. Marshall Institute
    17. Harvard Center for Risk Analysis
    18. Heartland Institute
    19. Heritage Foundation
    20. Independent Institute
    21. International Center for a Scientific Ecology
    22. International Policy Network
    23. John Locke Foundation
    24. Junk Science
    25. National Center for Public Policy Research
    26. National Journalism Center
    27. National Legal Center for the Public Interest (NLCPI)
    28. Pacific Research Institute
    29. Reason Foundation
    30. Small Business Survival Committee
    31. The Advancement of Sound Science Coalition (TASSC)
    32. Washington Legal Foundation

    And they often boost sales claims by buying up the books themselves.

    You really should read “Merchants of Doubt” by Naomi Oreskes and Erik Conway.

  14. Whatshisname says:

    Texans once thought (and prayed) the summer of 1980 would be the worst they ever experienced, but it is no longer even remembered as
    “notorious.” Neither is the summer formerly known as the “notorious summer of 1998.” The “notorious heat wave” of 2000 too has lost its moniker despite record temperatures of 109 degrees in Houston, 104 at Galveston, 109 at Corpus Christi, 111 at Victoria and 112 in Austin. The summer of 2008 tied 1998 as the warmest ever in Central Texas, then 2009 smashed both of them.

  15. Berbalang says:

    Bob @ 7: Yes, if events had gone differently, but they didn’t. Imagine coming into work to find your desk stripped of floppy disks and your hard drive missing. Sure, there is the stuff you remember from the files and you can tell it to people, but it really does no good to do so.

    And there is the matter of who took them. There were problems at the time with one of the janitorial staff and a Rush Limbaugh listening conservative co-worker who viewed me as “the liberal”, to list two of them.

    I would like to think the disks will surface at some point, but they were probably reformated and used for porn or mindless conservative rants.

    One thing I should add is that obtaining and reading some of them doesn’t give me any room to doubt that the professional deniers are anything but monsters.

    Sorry if this became a little bit too much TMI.

  16. AH1 says:

    Cherry-picking to depict global cooling:

    1998-2008: -0.15C/dec
    2001-2008: -0.09C/dec

    However, the overall trends overwhelmingly show warming.

    2000-2008: +0.13C/dec
    2000-2010: +0.32C/dec
    1988-2008: +0.06C/dec
    1964-2004: +0.17C/dec
    1992-2005: +0.35C/dec

  17. Tranche Demerde says:

    NASA, as Hansen notes in his latest “Global Surface Temperature Change” paper, describes “why GISS analysis yields 2005 as the warmest calendar year, while the HadCRUT analysis has 1998 as the warmest year”, saying “the main factor is our inclusion of estimated temperature change for the Arctic region”.

    The Hadley assessment and the NASA assessment are both not “truly global temperature” records. Note the use of the word “estimates” in Hansen’s paper. They are attempts to come with something that will be useful over time to anyone who wants to know what the global temperature is doing. Each is a more or less imperfect analysis of all data each organization considers relevant.

    Obviously, the way deniers distort these data is ridiculous, but we cannot deny that they have been effective.

    Hansen notes: “it is understandable that analyses of ongoing global temperature change are now subject to increasing scrutiny and criticisms that are different than would occur for a purely scientific problem”.

    Nature, June 10 2010 carried an opinion piece by Oreskes and Conway, authors of “Merchants of Doubt”, entitled “Defeating the Merchants of Doubt”. They note: “Whatever facts one supplies, the skeptics continue to challenge them or offer alternative explanations. One cannot call one’s opponent a liar because it just seems desperate and ad hominem. Nor does it work to debate their points, because that feeds into the controversy framework: the skeptics say there is a debate, you say there isn’t – voila, they have proved their point.”

    Oreskes and Conway suggest that scientists “have much to learn about making their messages clearer”, “the preponderance of evidence is such that scientists should now clearly label anthropogenic warming a fact”, they should “take time to learn their history so they have compelling historical facts at their fingertips for rebuttals”. They suggest that journalists “need to become much more sophisticated in their assessment of expertise”.

    Perhaps also it is time to fight back using the same tactics. It would prove interesting for the world to see the internal communications of those who fund the deniers.

  18. TheChuckr says:

    You can keep deleting my and others’ posts regarding the McShane & Wyler paper:

    http://www.e-publications.org/ims/submission/index.php/AOAS/user/submissionFile/6695?confirm=63ebfddf

    which thoroughly destroys the statistical underpinnings of the Mann hockey stick graph but that will not make it go away.

    [JR: Not! Even this flawed study vindicates the core conclusion: As Gavin Schmidt Real Climate notes, "The M&W paper will likely take some time to look through (especially since it isn't fully published and the SI does not seem to be available yet), but I'm sure people will indeed be looking. I note that one of their conclusions "If we consider rolling decades, 1997-2006 is the warmest on record; our model gives an 80% chance that it was the warmest in the past thousand years" is completely in line with the analogous IPCC AR4 statement. But this isn't the thread for this, so let's leave discussion for when there is a fuller appreciation for what's been done. - gavin."

    More to come soon!]

  19. villabolo says:

    @#14. sailrick says:

    These 32 organizations have all been involved in the tobacco industry’s campaign to deny the science showing the dangers of tobacco.

    They are all now involved in the campaign to deny the science of climate change.

    ********************************************************************

    Sailtrick, thank you very much for that list.

  20. ilikecherries says:

    It comes as no surprise that those holding most firmly to the bandwagon all too easily dismiss any question of the underlying science as being the views of kooks or quacks or paid for by big oil – apart from rare exception, this is not the case – but for bandwagonesques it is certainly an easy and comfortable position.

    It should also not be surprising that the experts who do question are usually retired or having blown the whistle, have moved out of these positions – after all, scientists have vested interests and careers as well and normally have to struggle to get any kind of funding at all.

    But following unprecedented government stimulus packages it is no surprise that governments (who fund the research) are very eager to justify a new carbon tax.