Confusion and distortion – has global warming stopped?

There’s a mantra circulating at the moment claiming that global warming “stopped 17 years ago.” It is of course being pushed by the pseudosceptics in the climate denial echo chamber. However, even people who should know better have been heard to repeat something like that.

Rodney Hide, a former New Zealand ultra conservative politician has assured us “The world stopped getting warmer 17 years ago. That’s incontrovertible” (see my post “Incontrovertible” is it, Rodney? for my take on that). And one of the commenters on my blog at  SciBlog seems willing to treat Rodney’s assurance as a simple fact. Of course the pseudosceptics proudly and loudly reassert similar claims.

But many of those repeating this mantra are attributing the claim to authoritative sources, like the the Intergovernmental Panel on Climate Change (IPPC) and leading climate scientists and institutions.

So what’s the truth. Has global warming “stopped?” Are climate scientists saying it has stopped?”

Short answer is actually no. Slightly longer answer is along the lines that the current rate of global temperature increase seems to have slowed, global temperatures may even have plateaued, but that doesn’t support a claim that global warming has “stopped!” Or stopped 17 years ago.

IPCC Chairman misrepresented

Firstly – lets deal with the use of Rajendra Pachauri, Chairman of the IPPC, as a source for this mantra. This appears to go back to a report in the Australian which claimed he  “acknowledged a 17-year pause in global temperature rises.”

Trouble is, there is no record to back up the claim and the IPCC communications office said it does not accurately represent Pachauri’s thoughts on the subject.

The only statement the Australian article actually attributed to Pachauri on this subject is that “global average temperatures had plateaued at record levels and that the halt did not disprove global warming.” And that is paraphrasing Pachauri and not quoting him directly.

As the blog Skeptical Science pointed out (see Did Murdoch’s The Australian Misrepresent IPCC Chair Pachauri on Global Warming?) if he “had he said that global surface air  temperatures have plateaued and that this doesn’t disprove global warming, he would be 100% correct.” And that is what a number of well-known climate scientists also have said. Usually no mention of 17 years and certainly no claim that global warming had “stopped” 17 years ago.

To help clarify I repeat below two figures from my recent post “Incontrovertible” is it, Rodney? These show global air temperatures for the last 17 years and for the long-term – since 1880.


Global temperature anomalies for 1996-2012 (Average annual temperature data from NASA’s Goddard Institute for Space Sciences),

Line plot of global mean land-ocean temperature index, 1880 to present, with the base period 1951-1980. The dotted black line is the annual mean and the solid red line is the five-year mean. The green bars show uncertainty estimates. [This is an update of Fig. 1A in Hansen et al. (2006).]

As I said about the first figure in my recent post:

“There’s a lot of noise so all we can say from that data is the warming rate is in the range of  -0.02 and 0.17 °C/decade (95% confidence level). That’s the problem with such short time periods.”

Putting short-term trends in context of long-term record

The data in the first figure must be put into the context of the longer term changes. And as the 2nd figure shows a number of short periods over the longer term which had a similar pattern to that in the first figure. It would be silly, especially with hindsight, to claim that global warming “stopped” in 1990, or 1985, or 1975, and so on. Yet this is what some people are doing.

It’s easy to find short time periods where the global temperature trend is not significantly different to zero – that’s the nature of a record with this sort of variability or noise. A record which also results from a number of factors and is therefore not a simple correlation with one cause.

So it is silly to cherry pick a short period and then make an absolute claim (global warming has stopped) – and especially to claim that somehow something happened in 1975 so that “global warming stopped 17 years ago. Think about it. Take that first figure a just select the last 10 years. The trend will also not be significantly different to zero – are we then going to claim something happened in 2002 to “stop” global warming?

No, of course not. The only reason 17 years is mentioned is that one can’t go back further than that without the trend being significantly different from zero. It’s a cherry-picked date – cherry picked to produce a non-significant trend.

Have IPCC models been disproved

Another common claim is that the very recent plateau, or decrease in the rate of global warming proves the scientific climate models are wrong.  More specifically I have often heard the claim that since this plateau has occurred while atmospheric CO2 levels continue to increase this proves that CO2 is not driving global warming. Even the claim that the plateau has somehow shown the scientific understanding of the fundamental properties of greenhouse gases is wrong.

The naivety of the last claim is to think that climate scientists  consider CO2 to be the only factor influencing the climate – they just don’t. Consequently one should not expect to see a simple correlation between global temperature and atmospheric CO2. Any attempt to understand or model climate change must include many more inputs than CO2.

As for models in general here is a couple of factors:

  1. All models are inaccurate. That’s just the nature of the attempt to understand complex systems – we can’t expect to get things perfect. And when anomalies occur this may actually help us improve the models by incorporating other factors or more realistic physical parameters. Despite this models have important uses as long as we understand their limitations.
  2. Models require inputs – inputs which may change, often unpredictably, over time. Therefore it is silly to expect model projections to always be correct or accurate further down the track.

For example, there could be weather conditions increasing heat inputs into the deep ocean which could not have been incorporated several years ago. Or there could have been an increase of particulates from increased coal use which had not been predicted. Political changes can produce economic changes which influence inputs. These are some of the ideas that have been suggested to help explain the current plateau or reduced rate of global temperature increase.

So the real test of the model is not to use inputs based on predictions made several years before, but to update inputs so that the model more correctly represents current situations.

But, more basically, it’s important to recognise that the global climate is complex. Simple mechanisms are not going to explain the details in the global temperature record. So be careful of people who advance simple explanations to discredit the science.

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19 responses to “Confusion and distortion – has global warming stopped?

  1. Dan Pangburn

    A simple, science-based equation that shows the factors that drive average global temperature is at Using only one widely available measurement set, the equation calculates average global temperatures since before 1900 with 90% accuracy. Added atmospheric CO2 has no significant influence.


  2. Dan – have you submitted your paper to a peer reviewed journal? If so has it been published? If not could you summarise the refee’s comments?

    A big problem I see is that you have not modelled the underlying causes at all well, relying on input of data rather than true modelling. If that is the case I am not surpised at your succes. Or the fact that you don’t improve the model much by adding CO2, it is already there in the empirical inputs you use.

    But the material in your link is vague and largely unexplained – hence my itnerest on any peer review you have had.


  3. Dan Pangburn

    A substantially more-detailed version of the work has completed peer review but has not yet been published. The referees understood and agreed with the approach. Comments were mostly to enhance clarity.

    I think that what you are calling ‘true modeling’ is like the 20 plus GCMs that the IPCC uses. The main problem with those models is that they do not include the most important cause. Then, with their tinkering and training of their models to match history, they set themselves up for the abysmal failure to predict the flat global temperature trend since before 2001. These models used the input data of added atmospheric carbon dioxide.

    The underlying cause that they neglected to include is the sunspot time-integral. They looked at solar cycle maximums and solar cycle durations, each of which correlate poorly, and decided that sunspots did not matter. Apparently they never thought to look at them together which is what the sunspot time-integral does. It is really quite simple. A low magnitude, long duration solar cycle could have just as much influence as a large magnitude, short duration solar cycle. The sunspot time-integral is the first primary cause.

    The second primary cause is the natural effective ocean oscillation of which the PDO is a primary contributor. It does not add or subtract energy from the planet and is modeled simply as a saw-tooth surface temperature with amplitude about ±1/5 °K with period 64 years and last maximum in 2005. This simplified method of accounting for ocean oscillations is built in to the equation with only the magnitude being fine-tuned to maximize over-all accuracy.

    Just these two underlying causes explain average global temperatures since before 1900 with 89.8% accuracy so all of the underlying causes that were not modeled must find room in the remaining 10.2%. It is the input data of sunspot numbers that is the primary underlying cause (the equation format does the numerical integration).

    Thus the only input data (when the influence of CO2 change is zeroed out) are the sunspot numbers (which are available on the web).

    The material isn’t vague. It’s really that simple. The climate scientists have become mired in the minutia.


  4. What’s the name of the journal it’s to be published in, Dan?

    I can understand your own preference or your own model, but as I said I believe you are inputting temperature data in one form or another, which will include the influence of CO2.

    However, your description was vague enough for me to be unsure so I look forward to the full version when published.

    Any idea when that will be?


  5. Pingback: Pseudosceptics are at it again – misrepresenting and attacking climate scientists | Open Parachute

  6. Dan Pangburn

    It’s the CHANGE in CO2 level that is demonstrated to have no significant influence.

    Perhaps my earlier work (but now superseded by the refined work linked above) might help. A direct link trips some spam traps but you can get to all of my earlier stuff by the link given in red at

    There is a lot of stuff there but don’t bother unless you really want to find out what caused the planet to warm up, why it stopped warming, and why it is now on a cooling trend.


  7. Dan, you didn’t answer my questions. What’s the name of the journal which will publish your paper and when will that be?


  8. Pingback: A New Zealand climate change pseudosceptic apologises! | Open Parachute

  9. Looks like Dan went silent.


  10. Steve Weiss

    I’m not a climate scientist, whatever that may be, however, I do work in the insurance industry which annually records claims due to extreme weather events and pays out billions in claims for these events. Part of the global warming alarmist agenda is the assertion that CO2 increases cause an increase in extreme weather events and that specific such events can somehow be traced back to humans loading up the atmosphere with CO2. However, if CO2 levels are at or near all-time highs how do global warming advocates account for a fall in 2013 in such insurance claims to $45 from $81 in 2012? That appears to be an inverse correlation, is it not? Surely claims must rise if CO2 levels are increasing. So, what is the truth, and what if the computer models are unreliable and inaccurate? Makes one wonder.


  11. Couple of things Steve:

    1: What the hell is this alarmist agenda? Certainly the science is telling us that there is a likelihood of increases in extreme weather events and anecdotal evidence also suggest this. But this is a matter of facts and observation – not agendas.

    2: No one suggests CI2 atmospheric concentrations have reached all time highs. What we have seen though is increases to record levels in the last few thousand years.

    3: As for insurance claims – I have no idea what your figures $45 and $81 mean. However,I would certainly be interested in trends in claim numbers due to extreme weather events. My understanding is that there is a general increase (and we certainly are seeing big increases in premiums) but that would be measured over decades – not over a single year.

    4: Computer models are always inaccurate in this sort of thing because of lack of precision and, more seriously, inability to predict economic scenarios.. However, the scientific assessment does produce a predicted range of likely temperature increases and these seem to be occurring.

    Finally, if you do work in the insurance industry could you obtain reliable long term data (over several decades) of insurance claimed due to extreme weather events? I would certainly be interested in that. Bit data for just 2 years are meaningless.



  12. However, if CO2 levels are at or near all-time highs how do global warming advocates account for a fall in 2013 in such insurance claims to $45 from $81 in 2012?

    You’re in the insurance industry, you tell us.

    But here is a hint, only in the strange world of Friedman economics and the minds of ACT Party members does the holy market control the laws of physics.

    (and please provide a cite for your figures above)


  13. This would be a good opportunity for Cedric to post a link to the video about how peer reviewed science works.


  14. I’m not a climate scientist…..

    Really? Gosh.
    We’ve never had someone talk about a science topic like that before.
    Except for the last zillion times.
    Joy? Meet Steve.
    Steve? Meet Joy.
    You two should talk science to each other. The rest of us get to watch and eat popcorn.

    joy | July 9, 2014 at 9:39 am |
    I know there is a yahoo fluoride poison group but I didn’t join it as I get too much stuff now in my inbox. Just a reminder about Iodine and Fluoride toxicity. iodine works to pull out heavy metals including “F” and there is plenty info out there on iodine deficiency in the U .S. No, I’m not a doc…

    You two were made for each other. Same stupid, just different labels.

    I’m not a climate scientist, whatever that may be….

    Is English your second language or something?
    Do you also have the same difficulty with other terms like “electric drill” and “television stations”?

    Part of the global warming alarmist agenda…

    Yep, it’s a konspiracy. How spooky-wooky.
    How does this “agenda” work? Who runs it? What are the nuts and bolts of the operation?

    Take NASA, for example. NASA is a world leader in climatology. NASA has been telling the world about climate change for decades now. Are they part of this “agenda”?
    Say it with me slowly.

    NASA | Ask a Climate Scientist: Climate Change and Humans


  15. This would be a good opportunity for Cedric to post a link to the video about how peer reviewed science works.

    Poor AD. His poor widdle feelings are hurt because I called him a moron and he ran away.
    Um, don’t care. 🙂
    Not even a tiny, little bit.
    I’m in my comfortable place right now.
    If you don’t want to be labelled a moron then there’s a really easy solution. Stop behaving like them.

    Science Works! How the Scientific Peer Review Process works


  16. Another link to the same video? How perfect.

    How the scientific peer review process works.
    I get it now.


  17. How the scientific peer review process works.
    I get it now.

    Actions speak louder than words. So far, you are just talk. Unless you can do something else other than what the nutters are doing, then you’ll get treated like a nutter.
    Life is tough that way.


  18. What would you like me to do other than just talk? Type, perhaps?


  19. What would you like me to do other than just talk? Type, perhaps?

    You could try not acting like a moron. Did that ever occur to you?


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