The 1300s were a really crappy time in human history. The Black Death was sweeping through Europe and Asia. Feudalism was still the predominate system of government, most people didn’t bother to name their children until they were teens and then let their children pick out their own names because child mortality rates were so high. To that dreadful list, you can add a miniature ice age.
Yes, I really did say a miniature ice age. It lasted about 500 years and then we nearly entered it again in the 1920s. The Earth doesn’t just orbit the sun creating cycles of seasons, it orbits in an elliptical manner at a tilt. The result is that roughly ever 2,000 years sees a miniature ice age in the northern hemisphere with a coordinating one in the southern hemisphere that do not hit at the same time (as only the north or the south can be tilted away from the sun at one time).
This mini ice age, known as the “little ice age” is a contributing factor to mortality rates of the Black Death, the plague that did significant damage to human populations in the 1300s and 1400s. The problem with finding the “end” of the “Little Ice Age” is that some natural disasters influence climate significantly. We can say for sure that by the mid-1800s, the Earth had tilted back so that the Northern Hemisphere was getting warmer again.
Famines began in the late 1200s, due to shorter growing seasons and colder temperatures in the northern hemisphere year round. Famines make people more susceptible to diseases and generally poorer health, meaning the strong able bodied populations that would have had much higher survival rates when the Black Death arrived, weren’t there.
There was a severe period of cooling in 1769 and 1770. Which contributed to the Great Famine of France that lead to the French revolution in the late 1780s.
The 1800s brought more complications, because Earth can be a bit fickle. The 1810s saw a series of large natural disasters, including earthquakes and powerful volcanic explosions. The earthquakes leveled towns and the one that hit along the New Madrid fault line in 1812 was so powerful, the Mississippi River ran backwards for several days. However, earthquakes don’t contribute to ice ages that honor goes to volcanoes. Ice samples from the Antarctic and Greenland shows that a massive volcanic eruption occurred around 1808 that caused enough ash to be flung in to the air to create the coldest decade recorded in history to that point – ie: a nuclear winter at the tail end of an ice age caused by tilting of the Earth on its axis.
This eruption was followed by several others between 1808 and 1816. In 1815, Mount Tambora had an eruption that was twice the size of the eruption of unknown origin in 1808. 1816 is known as the “Year Without A Summer.” A second nuclear ice age then occurred during the last years of the Little Ice Age. By the 1810s, the Earth would have been in the process of tilting back to the benefit of the northern hemisphere. Emphasis on should have been, as I lied earlier without realizing it….
I said earthquakes don’t contribute to ice ages, but that isn’t entirely true. Strong earthquakes can change the alignment of Earth on its axis. In 2010, an earthquake in Chile shifted the Earth on its axis by 3 inches, which doesn’t seem like much, but actually shortened the length of a day in the Southern Hemisphere by 2 seconds. It was an 8.8, the third strongest ever recorded in history. In late 1811 and early 1812, there were three earthquakes that shook the New Madrid fault line in the USA (northern hemisphere). The smallest is estimated at a 7.8 and occurred in January 1812. The largest was an 8.8 in February 1812. It is this quake that made the Mississippi River turn against its normal flow. On top of making the Mississippi River run backwards, it created a lake, and there were fissures that ran up to five miles long in the bootheel region of Missouri. It is impossible to imagine these 3 powerful quakes did not shift the Earth’s axis at least a little bit, given their magnitude, depth, and location (all of them happened in nearly the same location of Missouri, even though the fault runs into Tennessee, Kentucky, Arkansas, and the southern tip of Illinois).
While we don’t have proof, it seems likely that the powerful New Madrid earthquakes shifted the northern hemisphere a couple of inches further away from the sun, further shortening already shorter days due to the tilt of the axis during this normal orbit variation. That is coupled with 2 volcanic eruptions (in 1808 and 1815) that caused nuclear winters. Thereby extending the Little Ice Age longer than what the natural axis tilt would have created.