[getsmart-l] Climate Change in Medieval Times: Re: Added concerns about the negative impact of biofuels on food prices and food security

[Gloria Boxen]

 Climate Change in Medieval Times

Brian Fagan of the University of California has written about the Little Ice Age and now, the warm medieval period.  He was interviewed this week on Quirks and Quarks about his new book, The Great Warming.   Europe & Britain benefited last time round until it came to an end (800-1230).  Land became very productive, population increased, cities grew, cathedrals were built, and the Vikings crossed the Atlantic.  However, forests were cut down to feed the expanding population.  Then, in the early 1200's one crop failure occurred after another with persistent rain and large numbers died of starvation.   In the same period, the Americas experienced drought and generally arid conditions.  Eventually,  the Mayans' civilization collapsed because with prolonged drought their water storage system failed.  
http://www.waterhistory.org/histories/aguadas/ (see below**) 

http://www.cbc.ca/quirks/archives/07-08/mar01.html

Global Warming - the last time around.

              
 The changes we're making to our climate are much greater than anything that's happened in human history, but we have had episodes of warming before. In fact, we had a centuries-long preview of climate change during the Medieval Era. This week, we speak to anthropologist and historian Brian Fagan about his new book "The Great Warming". In it, he describes how that period of global warming changed the course of human history, bringing balmy temperatures and bountiful harvests to some, but devastating whole societies with drought and famine. 


http://www.brianfagan.com/reviews.html

Anthropologist Fagan  focuses on the medieval warming period (ca. 800-1300), which helped Europe produce larger harvests; the surpluses helped fund the great cathedrals. But in many other parts of the world, says Fagan, changing water and air currents led to drought and malnutrition, for instance among the Native Americans of Northern California, whose key acorn harvests largely failed. Long-term drought contributed to the collapse of the Mayan civilization, and fluctuations in temperature contributed to, and inhibited, Mongol incursions into Europe. 

Fagan reveals how new research methods like ice borings, satellite observations and computer modeling have sharpened our understanding of meteorological trends in prehistorical times and preliterate cultures. Finally, he notes how times of intense, sustained global warming can have particularly dire consequences; for example, “by 2025, an estimated 2.8 billion of us will live in areas with increasingly scarce water resources.” Looking backward, Fagan presents a well-documented warning to those who choose to look forward. Illus., maps.

Kirkus review, December 2007
                 What happened when the world grew warmer from 800 to 1200 CE. Drawing on data gathered during the past 30 years by climatologists using such modern tools as deep-sea cores, ice borings, computer modeling, tree and coral rings, Fagan (Fish on Friday: Feasting, Fasting, and the Discovery of the New World, 2006, etc.) offers a tentative history of the “Medieval Warm Period,” when rising surface temperatures produced sudden, unpredictable climate swings throughout the world. Although much remains unknown, there is good evidence that there were winners and losers in this period of global warming. It was a time of abundant harvests and the cultural achievements of the High Middle Ages in Europe, while other areas from the Americas to China and Eastern Africa experienced long periods of drought and famine. “Farmers went hungry, civilizations collapsed, and cities imploded,” writes Fagan. Prolonged drought stalks these pages, a silent killer the author considers a
 harbinger of what could happen during our own time of global warming. 

Medieval droughts lasted for decades in California and the American Southwest, he notes. Even the lower Hudson River Valley experienced arid conditions that, if they occurred today, would endanger urban water supplies. Much of the book describes how the Medieval Warm Period affected trade, warfare and other aspects of life. In Central America, drought repeatedly disrupted the lives of the Mayans, who relied on unpredictable water sources. Elsewhere, many rural societies coped by building canals for irrigation, borrowing food from neighbors in times of need, maintaining kinship ties with distant communities and moving there when droughts came. 

Today’s more densely populated planet, notes the author, with 250 million people living on agriculturally marginal lands, is far more vulnerable to long periods of drought, especially the developing world and such populous areas as Arizona, California and southwestern Asia.

http://www.islandnet.com/~see/weather/reviews/littleice.htm

The Little Ice Age: 
The Prelude to Global Warming,
1300-1850  by Brian M. Fagan 
---------------------------------
  As we enter the 21st Century, many believe that major climate changes are imminent, and of those believers, a portion maintain that we have the wisdom and technology to steel against the worst aspects of changes in climate and long-term weather variations. That is, most of our current global civilization is much less vulnerable to large swings of weather and climate than humanity was at the start of the just-completed millennium.


  [I must regress a moment to define a few terms. Short-term weather extremes are those weather events of a month or less that may be very destructive (e.g. Hurricanes Andrew or Mitch). Climate variations are changes in long-term weather conditions over periods of say, decades or longer. Long-term weather extremes are large variations of seasonal, annual, or even multi- annual conditions such as El Niño events.]

 
  Unfortunately, few of us have been exposed to research linking a long historical record of weather and climate fluctuations with social and national histories to make a true judgement concerning our ability to cope with such fluctuations. Too many of us have been prejudiced by recent media and environmental group claims that recent extreme weather-related events have been unique in human history. Nothing could be further from the truth, and thanks to several recently released books such as The Little Ice Age by Brian M. Fagan, we are now able to see current conditions in a better historical perspective.


  For me, Brian M. Fagan's The Little Ice Age leads that list of popular books relating history and climate. Fagan is an archeologist/historian whose many popular works have brought archeology to millions of readers. As such The Little Ice Age is not a scientific look at climate change (his brief attempt to describe the greenhouse effect continues the inaccuracy of the metaphor), and he breaks no new ground in the scientific search for recent (last few millennia) earth/climate history. However, he does smoothly weave the observational and proxy (obtained from agricultural records, ice cores, tree rings, etc.) seasonal and climate trend information of others into the historical record to show us the stress points that have altered the flow of history. Within this tapestry, he shows how climate change theories such as changes in the North Atlantic Oscillation and enormous volcanic eruptions such as Mount Tambora (causing the 1816, "Year without A Summer") fit the data and
 historical accounts of the day.


  The Little Ice Age, for which the book is named, is generally considered as an exceptional cold period between approximately 1300 and 1850. It followed the Medieval Warm Period (900- 1300) that saw the Vikings discover and settle Iceland and Greenland and push into the northeastern American coastal region, and vineyards thrive across much of the British Isles and high up Alpine slopes. The Little Ice Age ends (circa 1850) with the present warming trend that began concurrent with the onset of the Industrial Revolution.


  During the Little Ice Age, Europe and many other parts of the world suffered extreme food crises which led to starvation, epidemics, large-scale migration, changes in agricultural practices and political unrest. Fisheries disappeared or changed. British and many continental European vineyards failed, not to return until the 20th Century. Millions died from famine caused not only by bad weather but by bad agricultural practices and weak social structures. Traditional crops failed and were replaced by newer cultivars such as the American potato. The period was a most stressful time that caused the fall of some institutions and practices and the rise of others more in tune with prevailing climatic conditions.
  
Historians have long shied away from links between social history and environmental factors such as weather/climate changes, perhaps because much of our definitive knowledge about these fluctuations has only come recently, the result of scientific investigation replacing or affirming anecdotal evidence. Without confirming data in other records, for example, diaries or other records which speak of atmospheric conditions often have the limited sight of a human lifetime and the exaggerated viewpoint of someone gravely affected. With hard data to back them up, convincing connections between social history and climate can be made.


  Fagan has taken the recent explosion in proxy weather/climate data for the last millennium and scientific climate change theory to place it alongside the historical record of European society. Fagan states his purpose in writing this book thus:
 "In The Little Ice Age I argue that the human relationships to the natural environment and short-term climate change have always been in a complex state of flux. To ignore them is to neglect one of the dynamic backdrops of the human experience. ...Environmental determinism may be intellectually bankrupt, but climate change is the ignored player on the historical stage."  He concludes the book with:
  "The vicissitudes of the Little Ice Age reminds us of our vulnerability again and again. In a new climate era, we would be wise to learn from the climatic lessons of history."  I found Fagan's historical look at the influence of the swings of weather and climate of the Second Millennium an engaging and well-written account filled with timely examples and woven into a compelling argument that humanity was and likely still is very vulnerable to the vagaries of the atmosphere over longer time periods. We perhaps have been fortunate that advanced transportation systems have mitigated much of our concern over crop failures, but we should not become complacent that we are above danger. As the old saying goes, "those who ignore history are doomed to repeat it." Brian Fagan has hopefully opened our eyes to the dangers of being too smug.


  This is my first read of a book by Brian Fagan, but it will not be my last. His style makes history come alive and speak relevantly to me. If you are interested in either history or weather/climate, I strongly recommend The Little Ice Age. It should open your eyes to new connections between society and the world in which it functions. If you, like I, are interested in the historical and social aspects of weather and climate, The Little Ice Age is a must read.
   
 Keith C. Heidorn, PhD, ACM
THE WEATHER DOCTOR
10 June 2001 

**http://www.waterhistory.org/histories/aguadas/
Waterhistory-Aguadas, Cenotes, and ChultunsBACKGROUNDIn the lowlands of the Yucatan Peninsula and neighboring coastal regions where    the Maya settled, much of the land is underlain with an extensive, porous limestone    layer that contains a huge underground aquifer.  The rains quickly percolate down    to this aquifer.  As a result, surface water is scarce despite heavy tropical    precipitation.  Few rivers or streams exist in this region.
Yucatan Peninsula consists largely of coral-reef formations which emerged from    the surrounding ocean 5 million years ago.  As ocean levels dropped, groundwater    trickled into the cracks in the porous limestone and, over the millennia, carved    today's fragile network of underwater rivers, caves, and sinkholes.
WATER SUPPLY TECHNOLOGIESThe Maya used several water supply technologies to accommodate this environment.     An important source of water were underground caves called cenotes (se-NO-tes).     In addition to water supply, cenotes had important religious significance.  The    Maya considered them portals to the underworld, the place they journeyed in their    afterlife to meet gods and ancestors.  Yucatan's Department of Ecology has    identified and mapped over 2,200 cenotes.  The Maya sometimes    enlarged the cave entries to provide easier access.
There is a group of cenotes in Dzitnup, in central Yucatan's, an area of    traditional corn farming.  Visitors are often surprised that indigenous Maya are    still around, and that cenotes are the principal reason.  Ancient Mayans founded    villages near cenotes, the main source of water, and often kept these sacred    water holes secret from colonial powers.
The Maya used natural surface depressions as water reservoirs, lining many    to reduce seepage losses.  They also took advantage of water that was collected    in the depressions left when soil was removed for house construction (aguados).  At   Edzna (see illustration 1), there were 58 aguadas at    house mound sites that would have been suitable for  collecting and storing water.
Elsewhere the Maya constructed cisterns--call chultuns--in the limestone rock under buildings   and ceremonial plazas.  The Maya engineers devised drainage systems from buildings and   courtyards to divert rain runoff into the chultuns to provide year-round  water supplies in areas   where cenotes did not exist, such as in northwestern Yucatan.
A chultun investigated at Edzna is fairly typical.  It was bottle shaped in the cross    section with a narrow restricted neck and a large globular-shaped chamber below (see    illustration 2). The total depth of the Edzna chultun was    slightly more than 5 meters.
Chultuns were frequently lined with plaster to prevent seepage and averaged about    7,500 gallons each in capacity.  This is enough to supply about 25 people year-round.     Professor Sylvanus Morley, a noted researcher of Mayan civilization, reported that the    total chultun capacity available to some of the Yucatan towns could support from 2,000    to 6,000 people.
The ancient Lowland Maya typically employed one or more of the above technologies    for obtaining and  storing water, depending on local soil and rock conditions    (Matheny, 1983).  At sites like Edzna, only 12 chultuns have been    found.  But chultuns were widely used at nearby sites, such as Dzibilinocac, Santa Rosa    Xtampak, Labna, and Uxmal.  At Santa Rosa Xtampak, for example huge chultuns have been   found; the entire civic ceremonial area was served by chultuns.  At Dzibilinocac both chultuns   and wells were used, but wells were more important.  At Edzna, aguadas and canals were the   primary water supply.



John O'Gorman <jcogorman at sympatico.ca> wrote:        
 http://www.theglobeandmail.com/servlet/story/RTGAM.20080229.woxfordanal0303/BNStory/energy/
   Land conversion undermines  biofuels
  OXFORD ANALYTICA Globe and Mail Update  March 3, 2008 at 2:46 PM EST

  SUBJECT: The environmental  impact of biofuels.
 SIGNIFICANCE: Recent studies  indicate that biofuel production is likely to increase greenhouse gas emissions.  This suggests that some biofuels could have a greater environmental impact than  burning fossil fuels, if the cost of land conversion is taken into account.



  
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