The Younger Dryas is also known as “The Big Freeze.” Geologically it was a “brief” period in geologic terms composed of cold and drought. It was in sharp contrast to the former period of warming. It began roughly around 12.8 kya and ended around 11.5 kya. That means it roughly lasted for about 1300 years.
As far as we can tell the Younger Dryas began catastrophically! Climate conditions at the higher altitudes in the Northern Hemisphere rapidly changed into glacial conditions but just how rapidly this transpired is uncertain. Some scientists think it happened over a period of decades while others think it happened much faster and a few believe it was almost instantaneous.
According to the research of author and researchers Robert Felix (see link below) all ice ages in the past 250,000 years began in LESS THAN 20 YEARS and sometimes in LESS THAN 3 YEARS! That is utterly astounding and alarming because it means when the ice returns it happens suddenly not over hundreds of years.
Felix notes that at the end of the Eemian Period the climate descended from a warming period, which was either as warm as today OR WARMER, into a “full blown ice age IN LESS THAN 20 YEARS.” As he asks, can you imagine what such an event would do to our society today on a catastrophic scale? Like he says, this has happened over and over again. So why should we expect anything different this time around?
It is also interesting to note that the Younger Dryas began at around the same time as what is called the “Gothenburg Magnetic Reversal.” We should also keep in mind that the Younger Dryas began towards the end of the last glacial period on this planet so it is somewhat problematic to compare it to what might typically happen at the beginning of an ice age, mini or major.
As near as we can tell during the Younger Dryas Western Europe and Greenland experienced a cold period lasting roughly 1300 years. Some theorize that cooling in the tropical North Atlantic may have occurred prior to this cooling by a few hundred years. South America seems to have escaped the lengthy cold snap for the most part or at least it didn’t last as long there. It is also theorized that what is known as the “Antarctic Cold Reversal” started a thousand years before the dawning of the Younger Dryas. The ACR was a period of cooling in the planet’s climate during the last deglaciation period when the Pleistocene was giving way to the current Holocene period we are in today.
Climate change in the Andes during this time of the Younger Dryas appears to have been one of a colder and wetter climate. Researchers believe that in western North America the effects of the Younger Dryas were less intense than in Europe but there is evidence of glacial advances during that time! The Pacific Northwest also cooled and forests in Scandinavia gave way to glacial tundra. In general, around the world mountain ranges saw increased snow and glaciation and there was more dust in the atmosphere which originated from the Asian deserts. There appear to have been drought in the Levant (Middle East) which may have motivated the Natufian culture to begin engaging in farming. There was also a decline in Clovis Culture and an extinction event in North America during this time. Right now the prevailing theory of what caused the Younger Dryas is speculation that there was a SIGNIFICANT slowdown or shutdown of the North Atlantic Conveyor which circulates warm tropical waters northward. It has been theorized for several years now that this same North Atlantic current is slowing down today!
Whatever the cause the Younger Dryas had a significant effect on planetary climate for about 1300 years and the end of the last ice age apparently was not so quickly a dawning of a “paradise” of warmth and sun. So here’s a question…..
If the Younger Dryas heralded the current warming period we’ve been in for about the last 12,000 years and, thus, brought the most recent ice age to an end…..then is this also how another ice age begins???
I find the article appearing in LiveScience by Charles Choi rather interesting and here’s why. I saw the film entitled “The Day After Tomorrow” when it first came out. The original manuscript was written by Art Bell and Whitney Stieber who based it on current science of the time. As Choi points out the world gets gripped by sudden ice in a span of a few weeks which seems like sci fi BUT research suggests a similar event might in fact have happened in the time of the Younger Dryas. Choi also points out that there is no reason why such an event might not occur in the future! He also points out that such a great freeze could be precipitated if continuing changes in the Greenland ice sheet continue and it suddenly melts, ironically.
Choi goes on to point out that this Big Freeze (Younger Dryas) as near as scientists can tell was brought about by a vast influx of fresh water in a volume greater than the Great Lakes! All of this fresh water entered the Atlantic which, in turn, brought the “conveyor belt” current to an abrupt halt. He and others believe the source of all of this fresh water was the prehistoric Lake Agassiz in North America as it broke over its banks and diluted the circulation of warmer water in the North Atlantic and without this warming influence of the belt temps across the northern hemisphere plunged.
Choi also points out that the FACT is there is EVIDENCE of all this found in ice cores taken from the Greenland ice! Those ice cores indicate this climate change was abrupt and occurred within a decade or so. HOWEVER, new research has some researchers now saying that it happened within a FEW MONTHS OR A YEAR OR TWO AT MOST!! That’s alarming!
Apparently the climate system on planet Earth can turn on and off rather suddenly and once that happens there is little to no time for human to react. Researchers say there is NO REASON why a big and abrupt freeze shouldn’t happen again! If the ice sheet of Greenland melts suddenly this planet and all 7 billion humans on it are in BIG trouble!
Of course the melting of the Greenland Ice Sheet is one of the basic elements for arguing Global Warming but it MIGHT be that global warming leads to DRAMATIC COOLING somewhere down the road in the not to far distant future! Now isn’t that interesting? That would make both the global warming and global cooling advocates right! And I have a suspicion that is exactly what happens. First a warm up and then a sudden drop and cataclysm! We’d better start preparing for what comes AFTER global warming as it appears to be far worse than the warming.