The great rains of 1315 marked the beginning of what climatologists call the Little Ice Age, a period of six centuries of constant climatic shifts that may or may not be still in progress."
Not sure if the book would assist - I doubt somehow that there are records of the northern plains back then. But it does seem to indicate that once a pattern sets in - if seems to stay that way for more than one year. So perhaps it is an effect of the land masses on atmosphere and the Rossby waves. Indian cultures associated with cliff dwellings in the 4 corners area of the southwest in New Mexico, Arizona, Utah, and Colorado were abandoned around 1300 believed to be due to climate change.
Why the culture disappeared is hotly debated but the society was an agrarian society and depended upon snow melt to grow their crops. There is evidence that the culture moved from lower elevation valleys to mile high mesas during the late 13th centuries.
Some have hypothesized they were forced there by expanding tribes from elsewhere but little evidence of that exists. It could have been a response to disappearing mountain glaciers that fed their crops precipitating a move up the mountain where the streams still flowed year round before percolating into the ground. There perhaps they became victims of the LIA climate change that killed off the Vikings in Greenland as it turned cold with extensive periods of snow and ice on the ground.
That period Icefisher, as you know, also called the Neo-boreal period, or the Little Ice Age, (1600-1850) constituted what amounts to a period of colder and wetter climate conditions, heavy rains, also severe drought, famine, disease, high mortality rates and the resulting social and geopolitical instabilities - caused by global cooling.
The world is returning to a neo-boreal climate in my assessment; so there are serious considerations when it comes to food production, energy and population decline as a result of the global cooling regime I have forecasted to come.
This is because a colder, wetter climate can leave people hungry as global cooling can seriously harm crops, causing flooding, deep freezes, drought and famine. Hungry populations get weaker by a lack of nutrition and can become easily subject to disease.
Global cooling is so much worse than global warming. I will take the latter climate regime over the former any day.
There's a lot of historical evidence (as you pointed out with the Indian culture of the Americas and Vikings of Greenland) that many former empires were undone by climate change - that's global cooling.
The impacts would have been extended periods of drought leading to significant famine in what were formerly agriculturally-rich lands affecting cultures, their health, political/social strength and life spans.
The last gasp of what was the last serious cycle of global cooling would have been the years 1845-1851 - also known as the years of the Irish Potato Famine.
The Irish called it "An Gorta Mor," which translates to, "The Great Hunger." The potato famine hit Ireland very hard in the mid-1800s and destroyed most of Ireland's potato crops for half a decade.
The climate records of that era show that the weather was much wetter and colder than normal over Ireland in 1845. This brought into play a potato-disease of spores.
The spores came from ships bound from the Americas and around late 1844/early 1845, this potato blight also known as
phytophthora infestans (Latin for 'infesting plant destroyer') as the airborne spores swept through potato leaves above ground.
This, as the waterborne spores of the species had the help of the cooler and wetter than normal climate by ravaging the potatoes themselves throughout Ireland and continental Europe.
The astronomic transits of 1845 show this clearly in the climate conditions of 1845-1851.
The accounts said that: "... Potato leaves curled, withered and turned black... the tubers themselves often turned into a black, sticky, gooey mess ... infected potatoes that didn’t spoil in the ground spoiled after harvesting..."
It was said that potato blight "spread through Ireland’s potato fields faster than cholera did."
The climate conditions worsened with cooler and wetter conditions trying to save the losses of crops. Most Irish farmers tried to harvest their crops earlier than normal but that didn't work as the potatoes just spoiled over the winter season due to being harvested too soon.
By the end of 1845, it was recorded that one-third of Ireland’s potato crop had failed. The climate-forced famine began in earnest.
Potatoes are not natural to Ireland but were transplanted there from the mountains of Peru when the Spanish discovered the Peruvian Incas growing what the Spanish called 'the patata.'
These 'patatas' were shipped back to Europe and reached the U.K., where it become known as the 'potato.' In the late 1500s potatoes were introduced into Ireland.
That's when Irish farmers found that potatoes grew well in Ireland's moist cool soil. It was said that one acre of fertilized field could yield up to 12 tons of potatoes. That was enough to feed a family of six for an entire year. It's possible to live and remain healthy on potatoes alone.
So by the 1800s, the potato had become the staple Irish crop with somewhere around three million peasants existing solely on the potato - very rich in carbohydrates, minerals, proteins. This included a mix of vitamins like Vitamin C, Niacin and Riboflavin.
The cooler and wetter climate kicked in and resulting famine from 1845 lasted to about 1851, more or less. It killed over a million men, women and children in Ireland while another million Irish emigrated from Ireland to survive.
That basically was the bookend to the last serious global cooling cycle - the mid-1800s.
So, a return to global cooling, starting in the late Twenty-Tens, through the 2020s, peaking in the mid-2030s, then beginning its waning years in the 2040s towards its end in the early 2050s are forecasted by me.
The result would be floods, drought, famine along with blasting storms, heavier than normal rains in some regions with lack of rains in other regions. Crop yields would be less as the colder wetter climate gives rise to disease of plants and crop shock.
Adjustments by farmers and livestock producers means working more closely to avoid the climate change to global cooling, but that means starting right now since it will take years to make the adjustments needed by the time a climate of global cooling sets into place by the early 2020s. That's also the time I forecast the next major La Nina to arrive.