12,800 BP

Something happened, abruptly. The younger dryas cold period suddenly starts. There is a degree of consensus amongst paleo-climatologists that a sudden influx of glacier meltwater into the North Atlantic caused, amongst other climate changes, a drop in temperature in Europe of between 4 and 6 degrees. We are currently experiencing the climatic disruption caused by just 1 degree temperature rise, gradually over a hundred years. So imagine what the impact of a very sudden 6 degree temperature drop would be.

The climatologists generally do not speculate as to what caused a sudden surge of glacier meltwater into the Atlantic. Neither do they explain what kept the temperature low for 1200 years.

Though climate is complicated, there are in essence only two mechanisms that can substantially change global temperatures for a long period of time such as 1200 years, intensity of sunshine and how the Earth receives and keeps heat. The first of these depends on happenings in the sun. We know this does change and we have no easy ways to determine intensity of the sun in times past. This has no associated effects on earth except less warmth from the sun so it would not be an event that could be observed astronomically by people.

The second is the balance between the amount of sunlight reflected back into space and how well the atmosphere keeps the heat that is absorbed from escaping into space. Change in sunlight arriving at Earth and change in how much heat is absorbed and kept can of course both operate together.

There are three parts to the mystery of the younger dryas period, what caused the sudden change to a considerably colder climate, what then kept the Earth cold for the following 1200 years, and what then caused the sudden return to a warmer climate.

There is good evidence for a cometary impact on the Laurentide ice sheet at the start of the younger dryas period. This is the likely cause of the sudden influx of meltwater into the Atlantic. It could also have caused lots of volcanic activity. In addition to melting its way through thousands of feet of ice due to the great heat generated by the impact, it would also have sent great shock waves into the Earth. The fact that there is no impact crater to be found is simply because it made the crater in the ice not in the ground. The ice was 8000 to 10,000 feet thick in some parts of the ice sheet, so it is possible the meteor made a crater in the ice many miles wide. The cubic miles of heated water would then have melted more ice as it flowed into the sea.

The huge amounts of vaporised water and volcanic debris ejected into the atmosphere would have blanketed the Earth, cutting off sunlight and causing cooling. We know from the individual and relatively small (by comparison) volcanic eruptions in recent times, that material sent up into the stratosphere, above the Earth’s weather systems, can remain in the atmosphere for a very long time.

However if it was things happening on Earth, rather than change in intensity of the sun, that cause the younger dryas period, we need a theory as to why these persisted for 1200 years and why they then suddenly stopped, allowing the sun to heat the Earth’s surface as it used to. In many ways the end of the younger dryas period is much harder to explain than why it started - see the page on 11,700 BP.

In any event, mankind was well established at this period. The start of the younger dryas will have had a major impact on flora and fauna, and how easy it was to find food. If the start of the period was global cloud cover from a comet and volcanoes, then this will have been a terrifying event for humans. We should have every expectation of finding something about this time in the stories that have been handed down through the generations to us. It was a long time ago so the stories may have become confused. We shall have to look for the key elements of the changes humans experienced:

- a fiery comet coming hurtling into the atmosphere, before its massive impact.

- massive climactic disruption immediately following, would cause people to believe the object falling from the heavens was the cause for the disastrous decline in temperature.

- tsunamis from cubic miles of meltwater entering the Atlantic and from volcanic activity would cause widespread flooding.

- global blanketing by clouds would cause the moon, the stars and possibly even the sun to disappeared from the heavens, maybe for months or perhaps for years?

Finding these kind of stories in myths and religions would be a good pointer to the main cause of the younger dryas being events here on Earth rather than events on the sun.

Read the story for more.