Warming Has Paused, BOM Says!

Ken Stewart, 19 March 2012

Sorry, that title is a little misleading, isn’t it.  The Bureau of Meteorology didn’t actually say this, but the BOM’s own data does.  Loudly and clearly.Acorn 1995-2012

The Bureau’s brand-new, best quality dataset, ACORN-SAT (Australian Climate Observation Reference Network- Surface Air Temperatures) clearly shows the linear trend has been flat for 18 years.

So what of the Climate Commission’s report on “The Angry Summer” ,  and the Bureau’s apparent fixation with maximum temperatures in the past summer?

In the past, the BOM has been at pains to make clear that trends in climate can only be analysed over long periods of time. See for example, http://www.bom.gov.au/climate/glossary/climate.shtml   Three cold months have barely rated a mention in the past for this very good reason.  So why all the fuss over three hot months?  And if it is now OK for them to use a three month period in this way, surely it is OK for sceptics to point to a “pause” in warming over the past several years. A period of 18 years is 72 times longer than the “Angry Summer”!

In my last post I demonstrated how well Acorn annual mean anomalies from the 1981-2010 mean, match with UAH (the dataseries of atmospheric temperatures since late 1978 compiled by the University of Alabama- Huntsville):Acorn UAH 79-12 new

I was astounded that some commenters at the various sites where this was published had doubts about the accuracy of the UAH data.  You can’t help some people.  That’s why I decided to play the warmists’ at their own game, by using only the Bureau’s own data, which shows, among other things, that there has been zero trend in the data since 1995.

Finally, as the Climate Commission is not likely to mention these, here are some other not so widely known facts straight from Acorn:

  • 2012 had the coldest winter minima since 1983 Acorn winter min
  • 2012, at +0.11C, was the 36th warmest year- equal with 1995, just ahead of 1957.
  • The past three years- 2010, 2011, and 2012- were the coolest of the decade.
  • 2012 was cooler than 9 of the previous 10 years- beaten by 2011.  2011 was exactly at the median anomaly for the past 103 years, at -0.13C, according to Acorn’s homogenised record.

Meanwhile the Climate Commission would have us believe that because a three month period has been a record, this is somehow proof of man-made global warming.

Why?  Because that’s all they’ve got left.

5 Responses to “Warming Has Paused, BOM Says!”

  1. anthony Says:

    Great work Ken.

  2. Ian Says:

    Just a rant
    Comment from the BOM’s Special Climate Statement 43 on this summer.
    ‘However, the most extreme aspects of the 1972–73
    event were confined to inland areas, whereas in late 2012 and early 2013, 40 °C was reached at least once in every capital city except Brisbane and Darwin.’
    Makes you think – wow! A profound statement to make us believe that this summer was extremely hot. Until you check the data.

    In the summer of 1972/73, all capitals except Darwin, Brisbane and Sydney reached 40C. Sydney reached 39.9C at Sydney Obs but Sydney Airport reached 40C twice in Dec 72.
    So it’s true but only by 0.1C in Sydney.

    However, the Statement at least cites the real reason why both 1972/3 and 2012/13 were hot.
    ‘Like recent events, the 1972–73 heatwave coincided with the late onset of the northern Australian monsoon, preventing moisture and cloud of tropical origin from moderating temperatures inland.’

    I wonder what caused the hot summers of 1938/39 and 1894/95?

    Ken
    I can find the ACORN records for individual stations but not any trend graphs. Can you help me with the links for those?

    • Ken Stewart Says:

      Ian, I agree with you absolutely. It’s amazing what you find when you check the facts.

      There are no time series graphs for individual stations, you need to download the data from Acorn (AND from Climate Data Online for raw data) and make your own graphs, comparing raw data with Acorn. If you subtract Acorn from Raw you may find some surprises too.

      • Ian Says:

        Thanks, Ken.
        Recently I ran the raw data for Bourke, Jan 1939 and compared it with ACORN. Every temp over 30C was adjusted downwards and temps under 30C adjusted higher.
        This adjustment reduced Bourke’s 17 day +40C heatwave to 11 days.
        By the way, still can’t find out why 2009 has gone from the second hottest year to the third hottest year (behind 2005 and 1998) in just 12 months.

  3. It’s Official: a 27 Year Hiatus | kenskingdom Says:

    […] in March, I showed that there had been an 18 year pause in Australia’s mean temperatures.  In April I […]

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