The Little Ice Age spanned the early 14th and late 19th centuries as the Earth cooled enough to coat itself with ice. A painting (by Abraham Hondius) depicts ice skaters on the frozen River Thames in London around 1677. Entire villages near the Alps were engulfed by growing glaciers, which greatly affected the Northern Hemisphere. Scientists aren’t exactly sure what caused this extended, planetary cold snap, but many theories persist.
Possible Causes of the Little Ice Age
1. High volcanic activity: Ash clouds coating the earth’s atmosphere could block out the sun’s radiation and reduce temperatures. Volcanoes also emit sulfur, which transforms into sulfuric acid particles once it reaches the stratosphere. These particles reflect the sun’s radiation and therefore cause a cooling effect.
2. Decreased solar activity: This is a longshot of a theory, but scientists once believed that low sunspot activity (down to the Maunder minimum) could cause lower temperatures on Earth. This theory has since been debunked.
3. Orbital cycles: Differences in the Earth’s cycles could have caused enough of an axis shift to cool the atmosphere by 0.02 per century.
4. Changing ocean current flows: During the preceding Medieval Warm Period, enough melted freshwater ice could have altered the entire ocean and caused the water to cool down and stop circulating (in its usual conveyor belt pattern).
5. Decreased human population: Major population declines caused by rampant plagues and high infant mortality may have had the effect of decreased agricultural activity and reforestation. In turn, this would have altered the balance of CO2 and O2 in the atmosphere and created a cooling effect.
6. Inherent variability of global climate: Put simply, sometimes the Earth’s climate can fluctuate for no discernible reason at all, other than chaos theory.
Effects of the Little Ice Age
1. Megafauna: Animals that could survive during a Little Ice Age were generally large in size and swathed in fur. Saber-toothed cats, dire wolves, and short-faced bears flourished.
2. Great Famine: The icy weather drastically reduced crops and livestock. Faced with starvation from around 1315-1320, many regions of the earth entered crisis. Human cannibalism was not unheard of during these years.
3. Thirty Year’s War: Protestants and Catholics went to war over rising grain prices, which caused civil strife within countries and drove economies into the (frozen) dust.
4. Bubonic Plague: Rats (and their fleas) were able to survive the colder temperatures as human immune systems took a hit. The plague wiped out around 30-60% of the European population.
5. Witch Hunts: The powers that be wanted to blame someone for the frigid temperatures and aftereffects. Around 1484 until the end of the 17th century, Pope Innocent VIII blamed witches for these ills, which resulted in mass hysteria and executions all over Europe.
6. Potato dominance: This hardy crop made the transition to exclusive Spanish crop to a food that could be grown in the coldest of temperatures.
7. French revolution: Decades of poor harvests, high disease, and increased taxes resulted in civil unrest. These conflicts eventually culminated in the French Revolution of 1789.
8. Rise of the Bicycle: Horses were unable to survive after crop harvests dwindled to nothing, which left humans without transportation. This dilemma prompted Karl Drais von Sauerbronn to invent the first bicycle.
9. In the United States, A Migration: New England endured snowstorms in June, which caused residents to move into the Midwest.
The End of the Little Ice Age
By the mid-1800s, the glaciers of the European Alps unexpectedly began to shrink. Scientists believe that the soot (from coal and biomass) of the Industrial Revolution may have heated the atmosphere enough to return Earth’s temperatures to normal ranges.