North Australian Temperatures

For those of you think- “Gee it’s been hot with all these heat waves lately- it must be even worse up north”.

Here’s a plot of maximum temperatures across Northern Australia (the area north of 26 degrees south)  since 1985- the 29 years to the end of the hottest year on record.

tmax n aust 85-13

That trend is actually (very slightly) negative.

And yes of course it’s cherry picked- but 2014 will have to be a hotter than average year to make the 30 year trend positive- a 2014 anomaly of +0.35C gives a 30 year trend of: zero.  (The  mean of 1985-2013 maxima is +0.28C, the median is +0.34C.)

I guess the BOM is not hoping for a La Nina.

Data from Acorn.


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6 Responses to “North Australian Temperatures”

  1. Berynn Schwerdt Says:

    Please explain the rationale for the cherry-pick.

    Regional temps are not a proxy for global. Variability and local effects more pronounced. While 30 years is a good standard for global data, it is not equally good for regional, and even less so for sub-regional.

    That said, and in general response to the last few posts, lack of global diurnal range trend over the last 30 years is apparent and interesting. Bit premature to pitch it as a blow to global warming theory, .

    Following is a concise post on DTR as pitched by the IPCC over time.

    It was inspired by Fall et al 2011 (Anthony Watts’ paper), which found (tentatively) no diurnal trend in the US for a century, and I would say it is a fair, if too brief, critique of the issue.

    Ken, you may find yourself co-author on a published paper if you joined forces with Fall et al. Contact Anthony, if you haven’t already and that would interest you.

    • kenskingdom Says:

      Cherry pick precisely for reason stated- length of time with flat trend.
      No one mentioned ‘global’.
      BOM says 30 years is the minimum needed for analysing climate data.
      Australian region area is about comparable with USA so is worthy of study. If good enough for America… This post was merely about showing how Australian climate is not one entity. The north does not behave like the south.

  2. Berynn Schwerdt Says:

    Agreed that trends are different at different latitude, altitude, countries, land, sea surface.

    Australian region – about 1.5% of Earth’s surface area. 5% of the land surface area.

    BOM, porting me to CSIRO, state;

    Climate, on the other hand, is more stable, describing the average weather over at least 30 years.

    …a single warmer or cooler decade on its own is not sufficient evidence to assert climate change is or isn’t occurring, but statistically significant changes in average conditions over many decades do provide evidence of a changing climate.

    • Berynn Schwerdt Says:

      Agreed, weather and climate is different around Australia. Has anyone proposed otherwise?

      Climate change is detectable over ‘many’ decades. CSIRO describe 30 years as minimum required to assess average state, but doesn’t say that is also a good enough period to determine a trend. Logically, just off what CSIRO wrote, you’d need two 30-year periods to establish a climate change, but I wouldn’t argue that this is what CSIRO are saying.

      From much that I’ve read, I think 30 years is sufficient to determine a global trend (or not), but probably too short for regional, owing to greater variability.

  3. kenskingdom Says:

    Who cares what % Australia is- this post was about maximum temperatures in Northern Australia showing no increase over 29 years, showing Australia does not have just one climate. And the 30 year average for this period will be up at the end of this year. Not a single decade, 2.9 decades.
    And my confidence in CSIRO on climate is about the same as BOM. Zero.

  4. Berynn Schwerdt Says:

    Sorry, my reply appears above your last post.

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