Logic fail on record recorded temperatures

Yes, the World Is Getting Warmer

Another all-time temperature record:

Jeff Masters: Weather Underground: At 4pm local time today in Moscow, Russia, the temperature surpassed 100°F for the first time in recorded history. The high temperature of 100.8°F (37.8°C) recorded at the Moscow Observatory, the official weather location for Moscow, beat Moscow\’s previous record of 99.5°F (37.5°C), set just three days ago, on July 26. Prior to 2010, Moscow\’s hottest temperature of all-time was 36.6°C (98.2°F), set in August, 1920. Records in Moscow go back to 1879. Baltschug, another official downtown Moscow weather site, hit an astonishing 102.2°F (39.0°C) today. Finland also recorded its hottest temperature in its history today, when the mercury hit 99°F (37.2°C) at Joensuu. The old (undisputed) record was 95°F (35°C) at Jvaskyla on July 9, 1914. There is little relief in sight, as the latest forecast for Moscow predicts continued highs in the 90s for most of the coming week.

No.

The recording of record temperatures does not show that the world is warming*. The longer you measure a variable the larger the variations you measure will become. If you measured annual GDP change (just to get on track with Professor DeLong\’s thought processes) from 1950 ish to 2007 you\’d see at most a few percent either way. Extend that to 1920 to 2009 and you\’d see a couple of 10%, 15% even annual changes. Extend it to a few centuries and you\’d still not really see anything larger than 15% or so. Extend it to a couple of millenia and you\’d see much larger than 15%….the Black Death or the Sack of Rome (well, various of them perhaps) might qualify.

So, the recording of record temperatures in Moscow after 131 years is something we would expect….we\’ve near 50,000 daily measurements and as our measurements of the variable increase in number from 1 to 500 to 5,000 to 50,000 we would expect to see greater highs and lows being recorded.

* That the world is warming is true, but this isn\’t proof of it. What we want to know is what is the trend, not what are the occasional extremes. For example, as the Professor\’s own work shows us, while capitalism/free markets have increased annual variability over the centuries, the general trend has been upwards.

8 thoughts on “Logic fail on record recorded temperatures”

  1. “That the world is warming is true”: I suspect that it might well be, but I wonder how you know it to be true?

  2. And if you devoted the same assiduity to keeping an eye on climate change as you do to persecuting poor Ritchie, you would know that the jury is still out on AGW scam.

  3. “we would expect to see greater highs and lows being recorded.”

    Right, but we don’t. The number of record highs is increasing and the number of record lows is decreasing, as you’d expect when there is more heat about. Most of the records are recent (a third of them in the last 10 years),

    Also the observation of anything, for example new record highs this year, or each decade favors the theory that most strongly predicts it. As Jeff Masters says: “A record warm planet “loads the dice” in favor of regional heat waves more extreme than anything experienced in recorded history.”. If the planet were cooling or just shuffling heat about at random, it wouldn’t look like this.

    Tim adds: Err, yes, which is why I talked about trends. Read it again, please.

    The recording of a higher high than before is not evidence of global warming. It’s evidence of a longer time series. Trend is though evidence of global warming but trend does not depend upon the measurement of a record high.

    Which was the point I was making in the blog post.

  4. I understand the point you are making but it is still incorrect.

    If the broken records were really predicted just as well by having a longer time series, then you’d expect to see no difference to records being broken regardless of whether you extended a subset of the time series X amount to the left or the right – after all either way you will get a longer series.

    But if you do that to any data set that contains a trend you’ll find that it makes a big difference which way you extend the series. Therefore new observations on the right, aka ‘now’, do actually contain useful information about the trend.

    trend does not depend upon the measurement of a record high.

    But a warming trend makes measurement of a record high more likely, so it is in fact true that when you see one it constitutes some evidence of a warming trend. Again, not proof, evidence.

    As I said, observations favor the theory that most strongly predicts them, not just any theory consistent with them. In this case the theory that most strongly predicts the broken records is global warming.

    Yes you could get them by chance alone simply by having more observations, however it is less likely and that matters. Picking the most likely explanation will not always be correct, but that’s the way to bet.

    It would probably be possible to show this with some monte carlo simulations using artificial data with noise and with and without trends. Looking at record highs alone I believe you should be able to pick which ones have the trend added, better than by simply guessing.

  5. “If the broken records were really predicted just as well by having a longer time series, then you’d expect to see no difference to records being broken regardless of whether you extended a subset of the time series X amount to the left or the right – after all either way you will get a longer series.

    But if you do that to any data set that contains a trend you’ll find that it makes a big difference which way you extend the series. Therefore new observations on the right, aka ‘now’, do actually contain useful information about the trend. ”

    Tim is right. The measurement of a single record high in a 130 year series means precisely nothing in the absence of further characterisation of the data. If, in addition, record lows are not occuring then you may have a point.

    If there ARE also record lows occuring (and there have been eg in parts of Europe just last year) then one of two things may be happening; either a true increase in variability which says nothing about directional trends, or an apparent increase in variability, given that previous measurements were missed.

    Also I might add that when you say the sets “do actually contain useful information”, they might be statistically significant but whether the real-world significance is high enough to warrant restructuring the world economy is another question.

  6. “Arctic air and record snow falls gripped the northern hemisphere yesterday, inflicting hardship and havoc from China, across Russia to Western Europe and over the US plains.

    There were few precedents for the global sweep of extreme cold and ice that killed dozens in India, paralysed life in Beijing and threatened the Florida orange crop. Chicagoans sheltered from a potentially killer freeze, Paris endured sunny Siberian cold, Italy dug itself out of snowdrifts and Poland counted at least 13 deaths in record low temperatures of about minus 25C (-13F).

    The heaviest snow yesterday hit northeastern Asia, which is suffering its worst winter weather for 60 years. More than 25 centimetres (10in) of snow covered Seoul, the South Korean capital — the heaviest fall since records began in 1937.

    In China, Beijing and the nearby port city of Tianjin had the deepest snow since 1951, with falls of up to 8in and temperatures of minus 10C. In the far north of China, the temperature fell to minus 32C. More than two million Beijing and Tianjin pupils were sent home and 1,200 flights were delayed or cancelled at Beijing’s international airport. ”

    via the Times – six months ago

  7. The Pedant-General

    rech,

    Oh keep up will you: that’s weather not climate, so it doesn’t count.

    And of course neither do the record lows recorded across huge amounts of the US right through the winter, nor the record skiing season we’ve had in Scotland this winter or the equally record skiing season in NZ in their winter this time last year etc etc etc.

  8. Not withstanding P-G’s point, what we could be seeing is a regression to the mean for this part of the inter-glacial period. All we have to say that it isn’t is some much disputed tree ring data.

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