Wednesday, April 16, 2014

New paper finds worldwide glacier retreat has decelerated since 1950

A paper published today in The Cryosphere studies glacier length data available worldwide since 1800 and finds that glaciers retreated faster during the first half of the 20th century than the second half from 1950-2000. This is the opposite pattern that would be expected if man-made greenhouse gases were the cause, and suggests a natural origin. Most warmists and the IPCC claim man-made greenhouse gases did not begin to affect climate until after 1950, and thus can't be blamed for the fastest rate of glacier retreat from ~1850-1950 and subsequent deceleration

The authors find glaciers showed little change in length during the latter part of the Little Ice Age 1800-1850, but following the end of the Little Ice Age in ~1850 most began a relatively rapid retreat that began to decelerate after ~1950. The data shows that calving glaciers [red lines in fig 10a below] reversed to a net advancing trend after ~2001, and that the number of calving glaciers [fig 10b below] has sharply decreased from ~99% to 50% since the year 2000. 



The Cryosphere, 8, 659-672, 2014
www.the-cryosphere.net/8/659/2014/
doi:10.5194/tc-8-659-2014



P. W. Leclercq1,*, J. Oerlemans1, H. J. Basagic2, I. Bushueva3, A. J. Cook4, and R. Le Bris5
1Institute for Marine and Atmospheric research Utrecht, Utrecht University, Princetonplein 5, Utrecht, the Netherlands
2Department of Geology, Portland State University, Portland, OR 97207, USA
3Institute of Geography Russian Academy of Sciences, Moscow, Russia
4Department of Geography, Swansea University, Swansea, SA2 8PP, UK
5Department of Geography, University of Z├╝rich, Zurich, Switzerland
*now at: Department of Geosciences, University of Oslo, P.O. Box 1047, Blindern, 0316 Oslo, Norway

Abstract. Glacier fluctuations contribute to variations in sea level and historical glacier length fluctuations are natural indicators of past climate change. To study these subjects, long-term information of glacier change is needed. In this paper we present a data set of global long-term glacier length fluctuations. The data set is a compilation of available information on changes in glacier length worldwide, including both measured and reconstructed glacier length fluctuations. All 471 length series start before 1950 and cover at least four decades. The longest record starts in 1535, but the majority of time series start after 1850. The number of available records decreases again after 1962. The data set has global coverage including records from all continents. However, the Canadian Arctic is not represented in the data set. The available glacier length series show relatively small fluctuations until the mid-19th century, followed by a global retreat. The retreat was strongest in the first half of the 20th century, although large variability in the length change of the different glaciers is observed. During the 20th century, calving glaciers retreated more than land-terminating glaciers, but their relative length change was approximately equal. Besides calving, the glacier slope is the most important glacier property determining length change: steep glaciers have retreated less than glaciers with a gentle slope.

4 comments:

  1. I had the pleasure of discussing glacier retreat with James Balog of "Chasing Ice" fame, and Dr. Robert Bindschadler, retired NASA, on a recent Lindblad/National Geographic Antarctic voyage. Both seemed unknowledgeable about the history of glacier advances and retreats, perhaps because such information did not serve their anthropogenic global warming/climate change agendas. Dr; Bindschadler ridiculed my mention of warmer periods this interglacial, like the Medieval warm period, and denied knowledge of previous sea level high stands, such as during the Holocene Climate Optimum 8,000 to 4,000 years ago. Sadly, it appears that anything that predates Al Gore's alarmism is something that neither gentlemen cared to discuss. I consider both of them to be natural climate change deniers.

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    1. Yes, I get the same types of responses myself talking to scientists on the global warming bandwagon. Sad.

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  2. Channel Nine (Australia) Sixty Minutes last Sunday had a segment on the retreating glaciers of Patagonia. Obviously their go to scientist from U of Exeter hasn't read this paper and by the sound of him wouldn't want to either. His livlihood depends on AGW being real and dangerous.

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  3. Here are the details from the full paper. There was 69% more glacier melt globally (471 glaciers) between 1921-1960 than between 1961-2000.


    http://www.the-cryosphere.net/8/659/2014/tc-8-659-2014.pdf

    The data set contains the glacier length records for 471 [global] glaciers and it covers the period 1535–2011. There are glacier length records from all continents and at almost all latitudes. For the observed glaciers, the 20th century retreat was strongest in the first half of the 20th century.…. [T]he retreat is strongest in the period 1921–1960 rather than in the last period 1961–2000, with a median retreat rate of 12.5 m yr in 1921–1960 and 7.4 m yr in the period 1961–2000. [Globally, glaciers melted 69% more rapidly from 1921-1960 than from 1961-2000.]

    Also, just look at the graph (second link, jpg) from this paper below showing the hockey stick contribution to sea level rise during the 1920 - 1940 period compared to recent decades. (CO2 levels grew by just 8 ppm between 1920 and 1940.)

    http://journals.ametsoc.org/doi/full/10.1175/JCLI-D-12-00319.1
    [T]here was a warm period in the Arctic and Greenland in the 1920s and 1930s (Box 2002; Johannessen et al. 2004; Kobashi et al. 2011) at a time when anthropogenic global warming was relatively small (see, e.g., Fig. 9.5 ofHegerl et al. 2007). This promoted glacier mass loss at high latitudes in the Northern Hemisphere (e.g., Oerlemans et al. 2011) at a greater rate than the global mean. Although in L the difference is not striking in general (not shown; L includes 79 glaciers north of 60°N and 24 north of 70°N), it is pronounced in Greenland. Length records included in L indicate a greater rate of glacier retreat in the first than in the second half of the twentieth century in Greenland (Leclercq et al. 2012)

    [Graph from the paper (Figure A) showing much larger glacier melt rate contributions to sea level rise in the 1920s to 1940s compared to the present:]

    http://journals.ametsoc.org/na101/home/literatum/publisher/ams/journals/content/clim/2013/15200442-26.13/jcli-d-12-00319.1/20130821/images/large/jcli-d-12-00319.1-f2.jpeg

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