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Analysis Of Antarctic Peninsula Temperature Trends

May 22, 2015
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By Paul Homewood

 

I looked at temperature trends on the Antarctic Peninsula last week, and thought it worthwhile re-posting this analysis I did last August:

 

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It is commonly known that the Antarctic Peninsula has seen substantial warming in the last few decades. Jim Steele wrote a guest post for WUWT a couple of days ago,  “The Greatest Climate Myths of All”, which contained these observations about Antarctica:

As seen in NASA’s map of regional warming, the Antarctic Peninsula is another unusual “hotspot”, but relative to other climate dynamics, the contribution from CO2 is again not readily apparent. Stronger winds from the positive phase of the Antarctic Oscillation (AAO) increased regional temperatures without adding heat via 2 mechanisms.

First stronger winds from the north reduced sea ice extent by inhibiting the expansion of sea ice along the western Antarctic Peninsula and Amundsen Sea. As in the Arctic, more open water allows larger amounts of stored heat to escape, dramatically raising winter temperatures. Accordingly, during the summer when sea ice is normally absent, there is no steep warming trend.

The eastern side of the Antarctic Peninsula behaves in a contrary manner. There sea ice was not reduced and surface temperatures average 5 to 10° cooler, and the steep winter warming trend was not observed. However there was a significant summer warming trend. Previously during the negative phase of the AAO, weaker winds are typically forced to go around the mountainous peninsula. However the positive AAO generated a wind regime that moved up and over the mountains, creating anomalous foehn storms on the eastern side of the peninsula. As the winds descend, temperatures adiabatically rise 10 to 20 degrees or more due to changes in pressure without any additional heat.

I cannot comment on the science behind this, but I can show how the actual temperature records support what Jim says.

 

Let’s start with the western side, where we have two long running stations, the two British Antarctic Research stations of Rothera and Faraday.

 

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Rothera 67.34S 68.08W

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Faraday 65.15S 64.16W

 

First, winter temperatures, using GISS data. There is a clear and sizeable upward trend.

 

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And now summer. The trend at Rothera is slightly down, and at Faraday slightly up. (Note, though, the differences in scale to the winter graphs – at Faraday, for instance, we are only looking at a trend of less than half a degree in summer.)

 

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Crossing to the other side of the Peninsula, we find the station of do Marambio on the eastern side.

 

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do Marambio 64.24S 56.62W

 

In stark contrast to Rothera and Faraday, winter temperatures at the Argentine station of do Marambio are actually declining.

 

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Whilst in summer temperatures are increasing.

 

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The numbers certainly support Jim Steele’s arguments, and suggest that it is regional factors that have led to recent warming there.

Sources

Temperature data is from SCAR datasets (Scientific Committee on Antarctic Research), available via GISS.

http://data.giss.nasa.gov/gistemp/station_data/

12 Comments
  1. manicbeancounter permalink
    May 22, 2015 5:55 pm

    In my view a major part of understanding the issues of temperature homogenization (literally “making homogeneous” by removal the outlier data) is that there are genuine localized changes to temperatures. This is an extreme example of those local changes. Homogenization is necessary to get a regional or global average temperature map – the data is too sparse and are there are quality issues much much of that data to do otherwise. The data sparsity and quality issues are greater the further back in time you go. Along with adjustments normally being zeroized on the current data, this may explain many of the large adjustments you have been finding. It is something that can be modelled and tested.
    Now consider the definition of climatology.

    Climatology or climate science is the study of climate, scientifically defined as weather conditions averaged over a period of time.
    http://en.wikipedia.org/wiki/Climatology

    By pointing out, quite rightly, that there are significant local or sub-regional variations in temperature, you are providing empirical evidence that climatology is flawed. Me too. 🙂

    • johnmarshall permalink
      May 23, 2015 11:26 am

      Temperature averages are impossible to calculate for anything let alone a planet. Trying to calculate one for Earth is like trying to knit fog. The present data is from a limited part of the planet, 30% because oceanic temperatures are not accurate or easily available. Coastal temperatures are a result of surface temperatures for a cell, about 200Km sq, avaraged for the 200Km from the coast. Blatently wrong so homogenation is fiddling with poor data to get worse data.

  2. May 22, 2015 6:08 pm

    My results from southern Africa
    which is not too far above A.
    show
    a) average temps unchanged since 1976
    b) minimum temps. continue to decline [most probably due to loss of vegetation?>]: total about 1K down since 1976
    c) max. temps. increasing from 1976-2000, apparently offsetting the decrease in minima, until now.
    The future looks like cooling down, a bit

  3. May 22, 2015 7:08 pm

    Thanks, Paul.
    All climate is local, then weather gets homogenized and corrected for global purposes.
    Global Warming appeared thus. Climate Change should require a further epicycle.

  4. johnmarshall permalink
    May 23, 2015 11:19 am

    Jim Steel’s book explains the peninsular local conditions causing the temperature fluctuations very well. Landscapes and Cycles is worth a read.

  5. Kon Dealer permalink
    May 23, 2015 2:11 pm

    I was posted to Rothera in the mid-1990’s. They have a large airstrip, made from black cinder-like stones. The weather station is close by.
    In short a very unnatural state of affairs.
    A prime candidate for an urban heat island effect.

    • manicbeancounter permalink
      May 24, 2015 12:29 am

      At the other end of the globe there is a similar situation at Svarlbard Airport. the weather station is literally by the edge of the tarmac, as evidenced by pictures by WUWT
      http://wattsupwiththat.com/2010/05/13/where-the-is-svalbards-weather-station/
      The snow and ice are partly cleared by steam, salt being useless.
      Even without this , it is possible that the early twentieth temperature rise was at least as high as the late twentieth century rise, and that temperatures are now no higher than in the 1930s.

  6. September 22, 2016 4:35 pm

    If the temperature variation since 1950s is a part of a natural cycle (as you suggested), I’d like to see the paleoclimate studies from before that to see the RATE of temperature variations. Many people are alarmed by global warming, but geologically, it’s a natural cycle between Ice Age and Greenhouse Age. What is alarming, however, is the RATE at which this change is happening in the current era.

    I don’t believe that we have left the glacial stage of the last Ice Age, but I do believe that we are leaving it much faster than we are meant to. Natural variation could be the cause of changes in temperature in Antarctica, but it’s the rate at which it’s changing that is my issue.

    It’s this faster rate that is causing havoc everywhere else on the planet, ecologically and climate-wise.

    • September 22, 2016 6:46 pm

      There is no evidence that the rate is faster than in previous periods. Quite simply, we do not have ability to measure such short periods in the distant past.

      However, HH Lamb is clear that we have seen similar rates of both warming and cooling in the relatively recent past, such as the MWP, RWP etc

      BTW – Antarctica is not warming at all. The warming on the Antarctic Peninsula stopped about 20 years ago, and has been identified to be caused by natural causes. We don’t even know whether that was part of a cycle, because we no data beforehand

      • September 23, 2016 2:46 am

        Ice core studies can be used to check out previous data, but yes, i appreciate the problem of scale, it’s hard to get results to within a few decades.

        Now if that is the case, we cannot be sure whether the warming/cooling is at a natural rate. Even if it is, I think we should be worried and i’ll explain why.

        Warming in Antarctica may not be a problem (for whatever reason; upwelling of deep currents, natural variations etc) but warming in the Arctics is. And you cannot deny that there is no climate change happening in nature today. The rate of the overall climate change is close to 50 times faster than geologic history, and this has been validated scientifically.
        Debunking the entire concept of climate change just because the warming in Antarctica was possibly natural is only spreading misconceptions in a society where science education is abysmal and science explanation and understanding is even worse. Even if one is not debunking climate change in as many words, it’s what non-scientific readers TEND to think. And I think that is dangerous.

      • September 23, 2016 9:24 am

        Across the Arctic, it was just as warm as now in the 1930s.

        And of course I assume you are aware that ice cores show much higher temperatures than now in Greenland in the mwp

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