A pause or not a pause, that is the question.

With 2014 looking set to be the warmest year ever (possibly by some way) I’ve been wondering what position the people claiming “global warming has stopped” might retreat to. This neat tale hints at one possibility, and explains why it wouldn’t be a convincing argument.

Open Mind

UPDATE: A new post at RealClimate is very relevant, and well worth the read.


One day, a new data set is released. The rumor runs rampant that it’s annual average global temperature since 1980.

artdat

Climate scientist “A” states that there is clearly a warming trend (shown by the red line), at an average rate of about 0.0139 deg.C/yr. She even computes the uncertainty in that trend estimate (using fancy statistics), and uses that to compute what’s called a “95% confidence interval” for the trend — the range in which we expect the true warming rate is 95% likely to be; it can be thought of as the “plausible range” for the warming rate. Since 95% confidence is the de facto standard in statistics (not universal, but by far the most common), nobody can fault her for that choice. The confidence interval is from 0.0098 to 0.0159 deg.C/yr. She also…

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13 Responses to “A pause or not a pause, that is the question.”

  1. Scottish Sceptic Says:

    The pause exists otherwise you would not be discussing it because it is merely a slowdown enough to question whether the models are accurate. The real question is this: “did the models predict the pause”. OR to turn that around does the failure to warm since 2001 when we were told that the climate would warming “unequivocally”, been enough to show that we were not told the truth and the models are not valid. Or is the temperature warming anywhere near the 0.3C/decade that the IPCC told us it would (0.14 to 0.58).

    The answer is that it has not. The pause is significant only in that highlights the discrepancy between prediction and data and demonstrates the utter failure of the unequivocal models and the arrogant people who told us they were “unequivocal”.

    • andyextance Says:

      Did you read the blog entry? Your comment suggests not, because it refers to a made-up data set that was intentionally created without a pause, not real-world data. The fact it looks somewhat like our current situation – within the limits of uncertainty – is the point here.

  2. Richard Mallett Says:

    All you have to do is go to http://www.climate4you.com and look at the graphs for UAH, RSS, HadCRUT, NCDC and GISS. Do you see a ‘warmest year ever (by some way)’ ? And if you did, would that be a good or a bad thing ? This has been one of the best years for crop production.

    • andyextance Says:

      Here’s a statement from the World Meteorological Organisation, which is using an average of HadCRUT, NCDC and GISS:

      2014 on course to be one of hottest, possibly hottest, on record; Exceptional heat and flooding in many parts of the world

      Note the second part of the headline. It certainly suggests ‘a bad thing’.

      And here’s another, referring to your favourite dataset, the CET:

      2014 on track to be England’s hottest year in over three centuries

      • Richard Mallett Says:

        The WMO says the differences are a few hundredths of a degree, so we shall see what http://www.climate4you.com has to say in the New Year.

        As we have discussed before, it is difficult to establish whether the extreme events that always occur somewhere in the world can be attributed to global average temperatures, or if they are part of normal climate patterns that always happen from time to time. We must also consider that extreme events are better reported now than they were in the past.

        The sceptics would (and do) say that the alarmists can point to any extreme event and say that was caused by global warming and would not have happened otherwise. It is difficult to establish a trend in extreme events, and even more difficult to attribute a cause.

        Yes, 2014 was forecast to resume the upward trend in CET for some time, which is no doubt why the farmers are complaining of low food prices.

        The question is whether we should be spending our money on (for example) windmills or flood barriers.

      • Richard Mallett Says:

        I have now looked at the post on Real Climate, which is very interesting. Like my amateur analysis, it finds periods of cooling and warming, and stasis, from 1880, when CO2 was increasing all the time, so we need to understand more about the other causes of temperature changes (solar, clouds, ocean circulation, etc.)

      • Richard Mallett Says:

        Many thanks for that. In January, we will see the alarmists and the sceptics each picking their own favourite graph to show ‘warmest ever’ or ‘much the same’.

        As I mentioned, I will be looking at the records linked from http://www.climate4you.com – particularly those that cover the longest periods of time (HadCRUT, NCDC and GISS) and BEST if and when they update.

        (Satellite temperatures cover too short a time period to show the effects of cycles.)

        It is going to be interesting.

  3. Richard Mallett Says:

    Incidentally, the difference between HadCRUT4.2.0.0 and HadCRUT4.3.0.0 means that the 1850-2014 trend has gone up from 0.47 C per century to 0.48 C per century, so it will only take 417 years instead of 426 years to reach that magic 2.0 C warming that everyone is so worried about.

  4. Richard Mallett Says:

    Can you please quantify at what value ‘by some way’ would be statistically significant, and what global temperature data set you would use ?

    If we are talking about HadCRUT4.3, the 2014 anomaly is currently 0.565 C compared to the previous record of 0.555 C in 2010.

    Would an increase of 0.010 C be statistically significant, and would it merit the description ‘by some way’ ?

    • andyextance Says:

      My apologies Richard, that comment was a mistake. I mistook the Central England Temperature figure (which to my eye is set to be higher ‘by some way’ – a purely subjective judgement) for the global one.

      • Richard Mallett Says:

        Many thanks for that. The sceptic blogs are saying (a) that we should wait until the December figures are out in mid to late January (the GISS November figures are not out yet) and (b) that, if the anomaly is around 0.01 higher than 2010, it will be less than the measurement error by an order of magnitude.

      • Richard Mallett Says:

        I have now looked at the figures from http://www.metoffice.gov.uk/hadobs/hadcet/data/download.html and the only record that has been set so far in the monthly means (cetml1659on.dat) has been 10.2 C in April.

        All the other monthly means are below the highest ever, and all the seasonal means (ssn_HadCET_mean.txt) are below the highest ever; so it’s difficult for me to see where they get their green line from.

        All will be revealed in January 🙂


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