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California’s History of Mega Droughts

September 16, 2015

By Paul Homewood 

 

california_drought_timeline

 

You will no doubt have seen the above graphic already. It shows that the current drought in California is not exceptional by any stretch of the imagination.

 

We know that rainfall levels in recent years, though low, are not unprecedented as far as the 20thC is concerned.

 

multigraph

http://www.ncdc.noaa.gov/cag/time-series/us/4/0/pcp/12/8/1895-2015?base_prd=true&firstbaseyear=1901&lastbaseyear=2000

 

But, of course, one factor in determining the severity of drought is temperature. To put recent temperatures into historical context, it is worth revisiting the work of V C La Marche & V Markgraf, both experts on past climate.

As shown by HH Lamb in “Climate History and the Modern World”, they studied the height of the upper tree line in the White Mountains of California.

 

Scan

Their data shows just how much higher the tree line was in the Middle Ages, and before, and therefore how much higher temperatures were.

The reality is that California has been hotter and drier for much of its recent history.

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5 Comments
  1. dearieme permalink
    September 16, 2015 11:55 am

    Is the inhabited bit of California desert’s-edge, or just desert? Buggering up the use, storage, and distribution of water, and vastly increasing the population, will both prove powerful amplifiers as Mother Nature explores that conundrum.

  2. September 16, 2015 12:37 pm

    Thanks for the first graphic in particular. I have been looking for this.

  3. September 16, 2015 1:07 pm

    Mesa Verde, in southern Colorado, is a series of massive cliff-dwellings constructed late in the 12th century. Mesa Verdeans were involved in hunting, gathering and subsistence farming on the mesa tops with crops of corn, beans and squash. Mesa Verde was abandoned by 1285 following a series of severe and prolonged droughts when the inhabitants moved south to areas of Arizona and New Mexico.

  4. Don B permalink
    September 16, 2015 10:46 pm

    I have noted this elsewhere.

    Once upon a time, the NY Times was not the extreme climate campaigner it is today. From 1994:

    “BEGINNING about 1,100 years ago, what is now California baked in two droughts, the first lasting 220 years and the second 140 years. Each was much more intense than the mere six-year dry spells that afflict modern California from time to time, new studies of past climates show. The findings suggest, in fact, that relatively wet periods like the 20th century have been the exception rather than the rule in California for at least the last 3,500 years, and that mega-droughts are likely to recur.” [….]

    “The last century and a half, Dr. Stine found, has been the third wettest period in the last three millenniums. But, he said, “the vast majority of years during the past 3,500 years have been much drier than what we’ve come to expect to be normal in California.”

    http://www.nytimes.com/1994/07/19/science/severe-ancient-droughts-a-warning-to-california.html

  5. September 26, 2015 10:31 pm

    Reblogged this on Climate Collections and commented:
    Paul Homewood describes California’s drought history. He cites HH Lamb–an icon in climate study.

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