With all the talk of global warming is anyone scared at all of a forthcoming Ice Age? Probably not.
However there is a bit to be concerned about.
Having recently watched a documentary on the "Little Ice Age" which occurred circa 1300 AD to 1900 AD I was impressed by the conjecture that this ice age was perhaps caused by a previous period of warming.
Nobody can predict the weather with 100% certainty. So in reality there can be no certainty about what caused the Little Ice Age, but there are some remarkable similarities between our time and the era immediately before the "Little Ice Age"
Europe had been experiencing an unprecedented period of prosperity up through the Medieval period. The crops didn't fail. People were fed and the earth was warm.
But then it turned cold. Winter lasted longer and longer. The lows were lower and the highs were lower too. Crops began to fail and people got hungry. This was because the earth was cooling.
And it stayed cool for many years...about 600. People thought that witches were to blame, and thus the witch hunts of the 18th and 19th centuries.
Even the vikings were disbanded by the cool temperatures. Eventually the settlements in Greenland from the Medieval times were abandoned. Only the eskimos/inuit prospered.
In the 18th century the Hudson froze all the way over. History records that you could walk from Manhattan to the main land throughout the winter. It even snowed in the summer!
Some scientists believe that massive volcanic eruptions (which are backed up by sedimentary data) caused greater cloud formation which reflected sunlight back into space. This they think caused a climate shift.
However a very scary possibility is that the warm temperatures of the medieval period actually were responsible for the following ice age. The Atlantic ocean is home to a very complex and important phenomenon called the Thermohaline circulation. It conveys warm temperatures from the Gulf of Mexico along the eastern sea board all the way to Northern Europe. Europe would otherwise be a very cold and frigid place. Currently it's a very nice and mild place.
It's also called the Great Oceanic Conveyor Belt because the oceanic current (which is estimated by some to take 3200 years for a full cycle) cycles around the continents eventually making its way all the way back to the Gulf.
Here's the conjecture. The normal cycle of the GOCB keeps the earth happy and warm in Northern Climates. In the warm Medieval period it became so warm that much of the ice at the North Pole and Greenland melted into the ocean. The fresh and cold water was less dense than the warm salty water of the ocean and thus instead of sinking to the bottom of the ocean, where cold water was happily flowing, it stayed at the top disrupting the flow of warm water.
Eventually the conveyor belt was shutdown or disturbed and the flow of life giving warm water stopped. Europe got cold. The earth no longer had a properly working heat distribution system. And thus begin the "Little Ice Age".
It took another 600 years or so for the belt to resume and voila (as they say in France) the temperatures warmed back up.
The scary thing is that we see ice caps and massive snow melt in Greenland today. Could this be a sign of an oncoming ice age? I hope not. If it is, rising sea levels will be the last of our worries. Global famine, war and upheaval will become the norm, even more so than today.
The bad part is, nothing could stop it. Reducing GHG and CO2 could actually make it worse.