8,200 Years Ago

Extrait for the globalwarming awareness2007 site :

The climate change scenario outlined in this report is modeled on a century-long
climate event that records from an ice core in Greenland indicate occurred 8,200
years ago. Immediately following an extended period of warming, much like the
phase we appear to be in today, there was a sudden cooling . Average annual
temperatures in Greenland dropped by roughly 5 degrees Fahrenheit, and
temperature decreases nearly this large are likely to have occurred throughout the
North Atlantic region. During the 8,200 event severe winters in Europe and some
other areas caused glaciers to advance, rivers to freeze, and agricultural lands to be
less productive. Scientific evidence suggests that this event was associated with, and
perhaps caused by, a collapse of the ocean’s conveyor following a period of gradual
warming.
Longer ice core and oceanic records suggest that there may have been as many as
eight rapid cooling episodes in the past 730,000 years, and sharp reductions in the
ocean conveyer--a phenomenon that may well be on the horizon – are a likely
suspect in causing such shifts in climate.
The Younger Dryas
About 12,700 years ago, also associated with an apparent collapse of the
thermohaline circulation, there was a cooling of at least 27 degrees Fahrenheit in
Greenland, and substantial change throughout the North Atlantic region as well, this
time lasting 1,300 years. The remarkable feature of the Younger Dryas event was that
it happened in a series of decadal drops of around 5 degrees, and then the cold, dry
weather persisted for over 1,000 years. While this event had an enormous effect on
the ocean and land surrounding Europe (causing icebergs to be found as far south as
the coast of Portugal), its impact would be more severe today – in our densely
populated society. It is the more recent periods of cooling that appear to be
intimately connected with changes to civilization, unrest, inhabitability of once
desirable land, and even the demise of certain populations.
The Little Ice Age
Beginning in the 14th century, the North Atlantic region experienced a cooling that
lasted until the mid-19th century. This cooling may have been caused by a significant
slowing of the ocean conveyor, although it is more generally thought that reduced
solar output and/or volcanic eruptions may have prompted the oceanic changes.
This period, often referred to as the Little Ice Age, which lasted from 1300 to 1850,
brought severe winters, sudden climatic shifts, and profound agricultural, economic,
and political impacts to Europe...

The period was marked by persistent crop failures, famine, disease, and population
migration, perhaps most dramatically felt by the Norse, also known as the Vikings,
who inhabited Iceland and later Greenland. Ice formations along the coast of
Greenland prevented merchants from getting their boats to Greenland and fisherman
from getting fish for entire winters. As a result, farmers were forced to slaughter
their poorly fed livestock -- because of a lack of food both for the animals and
themselves -- but without fish, vegetables, and grains, there was not enough food to
feed the population.
Famine, caused in part by the more severe climatic conditions, is reported to have
caused tens of thousands of deaths between 1315 and 1319 alone. The general cooling
also apparently drove the Vikings out of Greenland -- and some say was a
contributing cause for that society’s demise.
While climate crises like the Little Ice Age aren’t solely responsible for the death of
civilizations, it’s undeniable that they have a large impact on society. It has been less
than 175 years since 1 million people died due to the Irish Potato famine, which also
was induced in part by climate change.

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