The Great Warming

Recent decades have been a golden age for archaeologists.  New technology has provided tools for better understanding the past.  Researchers can now identify the climate trends of past centuries by analyzing the layers in tropical coral, tree rings, glacial ice packs, and lakeshore and seabed sediments.

Climate has played a primary role in influencing the course of human history.  It could enable the rise of mighty empires, and later reduce them to dusty ruins.  Big changes can happen suddenly, without warning, and have devastating effects.  Mighty scientists may huff and puff and stamp their feet, but climate will do whatever it wishes.

In 2000, archaeologist Brian Fagan published The Little Ice Age.  This book examined an era of cooler weather spanning from 1300 to 1850, and its effects on northern Europe.  In those days, most folks lived from harvest to harvest, with few safety nets.  In 1315, it barely stopped raining, and the heavy rains continued through 1316 and 1317, followed by horrendous weather in 1318.  At least 1.5 million folks checked out.  The famine of 1344-1345 was so extreme that even the super rich starved.

Preceding the Little Ice Age was the Medieval Warm Period, which spanned from 800 to 1300.  Fagan described this era in The Great Warming, published in 2008.  Far less was known about this time, because fewer written records have survived.  But new climate data has been filling in a number of missing pieces, revealing many forgotten events, important stuff.

When it was in the mood for mischief, the Little Ice Age was a harsh bully.  Fagan had expected the warm period to be the opposite, and in some regions, it was, sort of.  In Europe, there were fewer late frosts, and the growing season was three weeks longer.  There were vineyards in England and southern Norway.  Surplus wealth enabled the construction of grand cathedrals.

Whilst the weather was rather pleasant, the era suffered from a devastating spasm of innovation.  The diabolically powerful moldboard plow, which was able to turn heavy soils, replaced the primitive scratch plow.  A new harness allowed horses to replace pokey oxen as beasts of burden.  The new three-field fallowing system enabled two-thirds of the fields to be growing crops every year, instead of just half, with the old two-field system.

By using these new technologies, vast regions of highly fertile heavy soils could now be converted into highly productive cropland.  The only obstacle was the vast ancient forests, and their untamed wildlife.  Loggers grabbed their axes and exterminated more than half of Europe’s forests between 1100 and 1350.

Expanded cropland area, combined with a balmy climate, produced much more food, and this always resulted in a mushrooming mob.  Between 1000 and 1347, the population of Europe grew from 35 to 80 million, despite short life expectancies.  It got so crowded that folks in 1300 were worse off than their grandparents in 1200.

In other regions, the warm period brought unpleasant weather.  The Mayans of the Yucatan lowlands experienced extended droughts and abundant misery.  “Hot, humid, and generally poorly drained, the Maya lowlands were a fragile, water-stressed environment even in the best of times,” Fagan observed.  “It’s hard to imagine a less likely place for a great civilization.”

The Mayan city of Tikal may have had 300,000 residents.  It was entirely dependent on rainfall for water.  Their ecosystem did not have dependable sources of water, like rivers or underground aquifers.  They developed amazing systems for storing rainwater, and these worked really well, usually, but not during multi-year droughts.  The drought of 910 lasted six years, and generated social unrest, which led to the collapse of many Mayan cities.

At the same time, severe droughts in western North America followed similar patterns.  Irrigation systems at Chaco Canyon enabled more than 2,000 folks to survive in an arid region for several centuries.  This worked well in wetter years.  After 1100, droughts intensified, and within 50 years the city was abandoned.

California was home to hunters and foragers.  Acorns were half of the diet for many tribes.  Oaks could produce as much food per acre as medieval European farms, and foragers could acquire a year’s supply in several weeks.  Fewer acorns fell in drought years, and extended droughts killed the oak trees.

Stumps at Mono Lake indicate that a severe drought began in 1250 and lasted for over a hundred years.  Fagan noted “None of today’s droughts, which last as long as four years, approach the intensity and duration of the Medieval Warm Period droughts.”  He called them megadroughts.  They baked away the surface waters and soil moisture.

The Yellow River (Huang He) has an appropriate nickname, China’s Sorrow, because it is one of the world’s most trouble-prone rivers.  Fagan said “the Huang He basin [has] been a crucible for human misery for more than seven thousand years.”  About 45 percent of the Chinese population lives in the basin.  From year to year, precipitation can vary by 30 percent.  A dry June is a bad omen.

To reduce the risk of famines, the Chinese built complex irrigation systems, which the Yellow River enjoyed burying with silt.  The yellow loess soil of the region was highly fertile, easy to till, and 200 feet deep (61 m) on average.  It was also light and easily erodible.  Once upon a time, forests held the soil in place, but deforestation* had catastrophic consequences.  The river carried an enormous load of yellow silt downstream, and this created perfect conditions for disastrous floods, which have killed many millions over the centuries.

This region has long been a spooky place to live, but the warm period was worse, “a time of violent climatic swings nurtured thousands of miles away that brought either lengthy dry cycles or torrential rainfall that inundated thousands of acres of the Huang He basin.”  (An extreme nineteenth century drought is described in Late Victorian Holocausts.)

Today, the global climate is hotter than the Medieval Warm Period.  The warming trend has been steadily building since 1860.  Glaciers are melting and folks are getting increasingly nervous about rising sea levels.  While this is indeed a bummer, Fagan warns that extended drought is a far greater threat.  Extended drought withers agriculture, toasts pastures, and dries up lakes and rivers.  Seven-point-something billion people will be extremely vulnerable when we move beyond Peak Food, and into the climate surprises of the coming decades.

Fagan, Brian, The Great Warming — Climate Change and the Rise and Fall of Civilizations, Bloomsbury Press, New York, 2008.

* In the 1930s, W. C. Lowdermilk, of the Soil Conservation Service, visited northern China as part of a research project.  In Shensi province, he saw an ancient irrigation system destroyed by silt, which had washed down from the uplands, where erosion gullies were up to 600 feet deep (183 m). 

He published his findings in Conquest of the Land Through Seven Thousand Years.  In this document, Figure 7 is a photo of serious erosion.  The caption reads: “A severely gullied area in the loess hills of North China.  These hills were once covered with trees and grass; but cultivation started the ruinous process of erosion.  There are thousands of acres like this in China today.  It produces nothing except yellow mud to clog the Yellow River with silt.”  For scale, note the human in the foreground.

The Little Ice Age

Once upon a time, Brian Fagan became curious about how history has been shaped by climate.  He did a remarkable amount of research, and then delivered a fascinating and very readable book, The Little Ice Age.  Mainstream history tends to focus on rulers, empires, wars, and technology, providing us with a pinhole perspective on ages past.  Fagan used a wide angle lens, and revealed how the miserable peasantry of Europe struggled to survive in a world of daffy rulers, steamroller epidemics, wildly erratic weather, and the ever-present threat of famine — a highly insecure existence in a world with no safety nets, and brief life expectancy.

Most of our detailed, regularly recorded weather data is less than 200 years old.  Older writings made note of climate conditions, times of prosperity, famines, plagues, and natural disasters.  More recently, we’ve discovered that tree rings and ice cores can provide climate information going back thousands of years.  The annual rings in tree trunks are thicker in ideal weather and thinner in lean years.  The annual layers of ice in glaciers are thicker in cold years, and thinner in warm ones.  In this way, climate leaves a fingerprint pattern that we can decode.  Ice also preserves ash residue, marking volcanic activity, which can have significant effects on weather.

While climate can vary from year to year, and day to day, modern climate science has discovered broader trends in weather patterns.  Fagan examined three trends: the Medieval Warm Period (900-1200), the Little Ice Age (1300-1850), and the warming trend of the fossil-fuelled industrial era. 

In northern Europe, the years between 800 and 1200 were the warmest period in the last 8,000 years.  There were vineyards in England.  Generous grain harvests fed a population explosion, which naturally triggered a rash of bloody conflicts.  Because of the warm weather, sea levels rose between 1000 and 1200, creating challenges for the lowlanders.  “At least 100,000 people died along the Dutch and German coasts in four fierce storm surges in about 1200, 1212-1219, 1287, and 1362.”

The kickoff for the Little Ice Age came in 1315, when it rained almost continuously from May to August.  Fields became lakes or knee-deep mud.  Floods erased entire villages.  Wars had to be cancelled.  The population, which had exploded between 1100 and 1300, now had to share a puny harvest, if any.

The survivors eagerly awaited a return to normal weather in 1316, but rains resumed in the spring.  Livestock diminished, crops failed, prices rose, and the roads were jammed with wandering beggars.  Many villages were abandoned.  People dined on pigeon dung, dogs, cats, and the corpses of diseased cattle (rumors of cannibalism).  By the spring of 1317, they had eaten their seeds, and had few oxen to plow with.  The rains returned.  There were seven years of bad harvests, creating steady employment for gravediggers.

For the next 550 years, the weather got colder, and there were more storms.  Frigid spells might last a season or a decade.  Cold weather was extreme from 1680 to 1700.  London trees froze and split open, and the Thames was covered with thick ice.  Chilly summers led to poor harvests from 1687 to 1692.  You could walk across the ice from Denmark to Sweden in the winter of 1708-09.  The All Saints Flood of November 1570 submerged the Dutch lowlands, drowning 100,000. 

This book is jammed with stories of weather-related problems — floods, droughts, crop failures, epidemics, famines, and food riots.  Most people struggled to survive via subsistence farming, using primitive technology.  Most didn’t have enough land for livestock, which meant little manure for fertilizer.  Under ideal conditions on prime land, planting a bushel of wheat would produce just four or five bushels at harvest time.  Because of this low productivity, feeding society required the labor of nine out of ten people.  Famine was common, and food relief was rare.  “Even in the best of times, rural life was unrelentingly harsh.”  “Farm laborers lived in extraordinary squalor….”

Fagan’s tales reinforced my dislike of agriculture.  It fuels overpopulation, converts healthy wild ecosystems into wreckage, enslaves plants and animals, and requires inequality and brutality.  It is proprietary — all the big juicy melons in that field belong to my group, and our field is strictly off-limits to any other creature.  This is the opposite of nature’s way, in which a big juicy melon is fair game for one and all, finders keepers.   

Private property turns humans and societies into obnoxious two-year olds — “that’s MY melon!”  Possessions become objects of wealth, power, and status.  If I steal your horse, then its power becomes mine.  In the insatiable pursuit of wealth, people will lie to your face, snatch your purse, cut your throat, bomb cities into ashtrays, and destroy entire planets.  You can’t farm without warriors to protect the real estate, livestock, and granaries, and you can’t control warriors without hard-fisted leaders.

The legions of hungry dirty peasants who produced the wealth were expendable, and lived in a manner that none of us would tolerate — while the lords gaily feasted.  “Excavations of medieval cemeteries paint a horrifying picture of health problems resulting from brutal work regimes.  Spinal deformations from the hard labor of plowing, hefting heavy grain bags, and scything the harvest are commonplace.  Arthritis affected nearly all adults.  Most adult fisherfolk suffered agonizing osteoarthritis of the spine from years of heavy boatwork and hard work ashore.”

 Today, our lives are unnaturally soft and cozy.  We exist in a “luxurious” unhealthy cocoon created by a temporary bubble of abundant energy.  The shelves at the store are always full, a wonderland of easy calories.  We have no memories of the hellish life of muscle-powered organic agriculture.  We have forgotten how recently our ancestors died from famines and pestilence.  As the cost and scarcity of energy increases, our bubble will surely pop.

Fagan gives us an eye-opening preview of what life is likely to look like when the fossil fuel bubble becomes the subject of scary old fairy tales (The Big Bad Consumer).  As our miraculous machines run out of fuel, we will have no choice but to slip and slide into a muscle-powered future, which will be anything but unnaturally soft and cozy. 

He also warns us that climate change is often not smooth and gentle.  History is full of sudden catastrophic shifts.  Despite our whiz-bang technology, and hordes of scientists, climate shifts remain beyond our control.  We will experience whatever nature decides to serve us — even if we exercised our famous big brains, and permanently stopped every machine today.  Climate was a persistent threat to agriculture-based societies long before coal mining was invented, because agriculture had far more defects than benefits.

This book provides vital information for those struggling to envision a sustainable future based on organic agriculture.  Ideally, enlightened humans will deliberately keep the transition to muscle-powered organic agriculture as brief as possible, whilst devoting immense wisdom to the essential goals of full-speed population reduction and rewilding.  There is nothing finer than a sustainable way of life.  All other paths lead to oblivion.

Fagan,Brian, The Little Ice Age — How Climate Made History 1300-1850, Basic Books, New York, 2000.