Tuesday, February 11, 2014

New paper finds North American droughts were far more severe & persistent during the past millennium

A recent paper published in Nature reconstructs North American drought history over the past 1,000 years and finds droughts during the 12th & 13th centuries were far more severe and long-lasting than the relatively mild US drought of 2012.


"Cook et al. tap a continental array of 1,000-year drought records based on tree rings to show how the 2012 pan-continental drought pattern has occurred in 12% of years since the tenth century. More importantly, the authors’ study highlights how no major US region is immune to such drought, and that we understand quite a lot about how sea surface temperatures drive the differing patterns of drought. Cook and colleagues’ most relevant lesson for the future, however, may be that the one- year pan-continental drought of 2012 was but a glimpse of drought compared with the multi-decadal pan-continental megadroughts that were most common during the twelfth and thirteenth centuries."

Climate science: The challenge of hot drought

Published online
An analysis of North American drought variability over the past millennium shows that it is not unusual for widespread drought to persist for years, prompting fresh thinking about our ability to deal with such climate conditions.


  1. The 12th & 13th centuries were NOT during the Little Ice Age, but during the Medieval Warm Period. MWP was roughly 900s-1200s (the 10th-13th centuries) and LIA roughly 1300s-1800s (14th-19th centuries).

    The long duration drought during the MWP corresponds to the findings in this paper (http://www.pcas.org/vol35n23/3523boxt.pdf) which in short says So. California was very dry during the MWP and much wetter during the LIA.

    1. Thanks for the ref., which only applies to So. California, which tends to be more highly influenced by ocean cycles, whereas this paper reconstructs drought from multiple locations in N America.


      I corrected the title and post accordingly regarding LIA

      Evaporation, water vapor, precipitation, floods, droughts are far more complex than the climate simpletons pretend that it is - see links here for example:

      Pan evaporation data worldwide show evaporation not primarily related to temperature:



    2. The "Little Ice Age" denotes several centuries when conditions were cooler than before or after.

      Anonymous is of course correct in stating that the 13th century not normally included as part of the LIA in the strict sense.

      However, in the broad sense, including the 13th Century is not necessarily wrong. At least H. H. Lamb would probably not have disagreed with the author of this blog.

      I base this on a paper posted as a PDF file here:

      On page 1 of the PDF there is a graph that H. H. Lamb used in his book. Climate, History and the Modern World, 2nd ed. Routledge, 1995.

      I have lost my first edition but believe this graph was also included.

      I realize that it is well known that in his later years Lamb supported the AGW hypothesis. Of course he had to in order to get funding for his GRU.

      However, Lamb convinced me that climate change is natural, not man-made.

      I believe that his arguments are valid today, I also believe that AGW is not verifiable scientific theory.

      Much like Freudian psychology and Marxism, whenever theory does not predict observations, AGW finds new ways to prove itself.

      AGW cannot be falsified, at least not with the science we have today. Perhaps like other end-of-the-world cults it will simply die when its followers lose faith.