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New Paper Finds No Evidence Of Long Term Flood Trends

October 5, 2017
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By Paul Homewood

 

 

Another study finds there is little evidence that floods are getting worse because of climate change:

 

 

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ABSTRACT

Concern over the potential impact of anthropogenic climate change on flooding has led to a proliferation of studies examining past flood trends. Many studies have analysed annual-maximum flow trends but few have quantified changes in major (25–100 year return period) floods, i.e. those that have the greatest societal impacts. Existing major-flood studies used a limited number of very large catchments affected to varying degrees by alterations such as reservoirs and urbanisation. In the current study, trends in major-flood occurrence from 1961 to 2010 and from 1931 to 2010 were assessed using a very large dataset (>1200 gauges) of diverse catchments from North America and Europe; only minimally altered catchments were used, to focus on climate-driven changes rather than changes due to catchment alterations. Trend testing of major floods was based on counting the number of exceedances of a given flood threshold within a group of gauges. Evidence for significant trends varied between groups of gauges that were defined by catchment size, location, climate, flood threshold and period of record, indicating that generalizations about flood trends across large domains or a diversity of catchment types are ungrounded. Overall, the number of significant trends in major-flood occurrence across North America and Europe was approximately the number expected due to chance alone. Changes over time in the occurrence of major floods were dominated by multidecadal variability rather than by long-term trends. There were more than three times as many significant relationships between major-flood occurrence and the Atlantic Multidecadal Oscillation than significant long-term trends.

http://www.sciencedirect.com/science/article/pii/S002216941730478X#%21

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7 Comments
  1. October 5, 2017 5:14 pm

    Reblogged this on Climate Collections.

  2. October 5, 2017 7:14 pm

    There 2 tweets that mention this URL
    http://www.sciencedirect.com/science/article/pii/S002216941730478X

    yet thousands of tweets mention Tuesday’s scare story that in a few decades Sydney and Melbourne will have occasional 50C temps.

  3. October 5, 2017 7:15 pm

    Interesting tweet , that I haven’t check the data for

  4. October 5, 2017 7:25 pm

    My error in the last bit there, the Sydney/Melbourne prediction is for 2100
    as Phoenix44 pointed out …drastic predictions for 83 years time have no reliability.

  5. October 5, 2017 7:45 pm

    ‘Floods are getting worse because of..building on flood plains’ might have been a better study.

  6. Geoff Sherrington permalink
    October 6, 2017 1:29 am

    For Aussie floods I have no personally-studied data, but re Sydney & Melbourne to face 50 deg C days, here is some history using official BOM data. Geoff.

  7. Bitter&twisted permalink
    October 6, 2017 7:03 pm

    But floods and other extreme weather events are happening in the models, so it must be true.

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