04.3.2019

The Little Ice Age – Back to the Future

,Mann concluded “the Little Ice Age may have been more significant in terms of increased variability of the climate”.  Indeed, historical documents from the Little Ice Age describe wild climate swings with extremely cold winters followed by very warm summers, and cold wet years followed by cold dry years. A series of Little Ice Age droughts lasting several decades devastated Asia between the mid 1300s and 1400s. Resulting famines caused significant societal upheaval within India, China, Sri Lanka, and Cambodia. Bad weather resulted in the Great Famine of 1315-1317 which decimated Europe causing extreme levels of crime, disease, mass death, cannibalism and infanticide.The North American tree-ring data reveal megadroughts lasting several decades during the cool 1500s. The Victorian Great Drought from 1876 to 1878 brought great suffering across much of the tropics with India devastated the most. More than 30 million people are thought to have died at this time from famine worldwide. The Little Ice Age droughts and famines forced great societal upheaval, and the resulting climate change refugees were forced to seek better lands. But those movements also spread horrendous epidemics. Wild climate swings brought cold and dry weather to central Asia.  That forced the Mongols to search for better grazing. As they invaded new territories they spread the Bubonic plague which had devastated parts of Asia earlier. In the 1300s the Mongols passed the plague to Italian merchant ships who then brought it to Europe where it quickly killed one third of Europe’s population. European explorers looking for new trade routes brought smallpox to the Americas, causing small native tribes to go extinct and decimating 25% to 50% of larger tribes. Introduced diseases rapidly reduced Mexico’s population from 30 million to 3 million. By the 1700s a new killer began to dominate – accidental hypothermia. When indoor temperatures fall below 48°F for prolonged periods, the human body struggles to keep warm, setting off a series of reactions that causes stress and can result in heart attacks. As recently as the 1960s in Great Britain, 20,000 elderly and malnourished people who lacked central heating died from accidental hypothermia. As people with poor heating faced bouts of extreme cold in the 1700s, accidental hypothermia was rampant. What caused the tragic climate changes of the Little Ice Age? Some scientists suggest lower solar output associated with periods of fewer sunspots. Increasing solar output then reversed the cooling and warmed the 20thcentury world.  As solar output is now falling to the lows of the Little Ice Age, a natural experiment is now in progress testing that solar theory. However other scientists suggest it was rising COthat delivered the world from the Little Ice Age. Increasing COalso has a beneficial fertilization effect that is greening the earth. The 20th century warming, whether natural or driven by rising COconcentrations, has lengthened the growing season. Famines are being eliminated. Tree-lines stopped retreating and trees are now reclaiming territory lost over the past 500 years. So why is it that now we face a climate crisis? At the end of the 1300’s Great Famine and the Bubonic Plague epidemic, the earth sustained 350 million people. With today’s advances in technology and milder growing conditions, record high crop yields are now feeding a human population that has ballooned to over 7.6 billion. So, the notion that cooler times represent the “good old days” and we are now in a warmer climate crisis seems truly absurd. Jim Steele is retired director of the Sierra Nevada Field Campus, SFSU and authored Landscapes and Cycles: An Environmentalist’s Journey to Climate Skepticism This article appeared on the A Walk on the Natural Side website at https://perhapsallnatural.blogspot.com/2019/04/the-little-ice-age-back-to-future.html]]>

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