A New Ice Age, or Global Warming?  

Science Fridays

      We're almost half way into April here in Minnesota, and we're having another week of winter storm warnings.  We had a full fledged blizzard today in the northern part of the state, and this was day three of the white crap for the southern part of the state.  It makes people wonder, "where is this global warming that we've been promised?  Are we experiencing global warming, or are we entering a new ice age?"  
      Let's start to answer that with a few facts about ice ages.  According to the paleo-geologists the earth has undergone several of them, but most of them were during the Hadean geologic eon.  There was another big one at the end of the Devonian, one really big one at the end of the Permian, and another at the end of the Triassic.  The Cretaceous meteor impact caused not just one, but five ice ages.  The first one happened right away as a result of the sunlight being blocked from the Earth.  However, the meteor hit the planet hard enough that the Earth got knocked out of its orbit.  We now orbit farther from the sun than we used to.  The Earth will never again be as warm as it was during the Paleozoic or Mesozoic eras.  The ice caps are here to stay, and they will occasionally spill over into the lower latitudes.  I've never read anything about the causes for the moons orbit to be farther out than it was before, but this might be the reason for that too.
      A second reason for the frequent ice ages since the meteor impact is how the continents split up and bashed back together again.  North and South America used to be separated, and so was Africa from Eurasia.  Also Africa and South America used to be connected (Gondwana), and Europe used to be connected in a continent called Laurentia.  Both Laurentia and Gondwana split along the Mid Atlantic Ridge (some think this is due to the meteor impact, but I'm not one of them).  Then Africa slammed into Eurasia, and North and South America collided after that.  Before all this massive continental movement, equatorial  and tropical water currents circled the globe unhindered.  The polar currents stayed near the poles as well.  If our ocean temperatures were color coded, the oceans would have been banded and would have looked like Jupiter or Saturn.
      After the closing of the east-west Ocean currents the ocean's water then flowed in a polar to tropical pattern.  This brought the cold polar waters south, thus cooling the planet.  As the cycle now goes, every so often things warm up so much that the polar ices begin to melt, bringing more very cold water toward the tropics and the Earth cools down.  Then an ice age sets in and the earth drys out because so much water is locked into ice.  With less cold water making its way to the tropics, the earth warms up again, and the continental glaciers recede.  This is a repeating cycle.  Sometimes it is a mild cooling/warming, and sometimes it is quite severe.  The last cycle of cooling began in what is called the "mini-Ice Age." 
       I have an excellent ancient history reference book that is called "Conquest by Man."  It was published in 1954, and was written in Germany by Paul Herrmann.  Its German title is "Sieben Vorbei und Acht Verweht"  It covers the history of man from the late Mesolithic to the Age of Exploration.  Herrmann used many resources for his work, including the logs of ships' captains.
      It is because of one such captain's log, that we can pinpoint for a certainty the year that the Min-Ice Age began.  In the summer of 1342 Ivar Bardsen sailed to the Western Settlements of Greenland.  He saw that the settlements were empty, and all that was there were the livestock of sheep, cattle, goats, and horses grazing in the fields.  There was no sign of anybody there.  They checked on the Skraeling settlements to see if the Greenlanders had been captured, but the Skraeling settlements were empty too.  Bardsen states that they returned to the Western Sttlements and took all the livestock they could and killed the rest for mercy's sake, as they wouldn't have survived the coming winter.

      Previous to this the Greenlanders were able to grow enough hay for farmsteads that had an average of 350 stalls.  That's a lot of hay.  Besides this they even grew their own grain.  In one year's time the climate cooled so fast that they could no longer grow the grain, nor even enough hay to last the winter.  They abandoned their settlement.  They didn't go to the other settlements though, because according to the Bishop of Greenland (who finally visited his bishopric) "the Western Settlements had gone the way of the Skraeling."  He went on to describe how they dressed like the Skraelings, and worshiped their gods, and although they still spoke Norse, they also spoke the language of the Skraeling.  I therefore conclude that they left Greenland with the Skraelings (note: these Skraelings were not the Eskimos/Inuits who inhabited these regions later, but were an Annishinaabe speaking people closely related to the Naskapi). We know that 1342 was the year they abandoned the colony, because the animals were still alive and grazing in the fields when Ivar Bardsen got there in early August. 
      What lessons can we learn for today from this?  The Mini-Ice Age began very quickly and set in in just a year or so.  We know that up until that time the Earth's climate was warm enough that you could grow an immense pile of hay and even grow grain in Greenland.  Today you still can't even grow a crop of hay there, much less any grain.  Are we experiencing global warming? (despite the very late arrival of spring this year - that is still normal too - in 1988 we had snow up here on May 10th and 11th)  Yes, the earth is warming.  Also, if it can cool down rapidly in about a year it could get warm AGAIN just as fast.  Oh no!  Should we panic?  No, these cycles are normal.  The "Chicken Littles" are squawking about how we need to walk to work, turn off our heaters and bundle up as we eat cold food in the dark to prevent this, because we are "colder than normal" they say.  Well, according to this recent, recorded history (1342) we haven't even seen true normal.  It's still too cold to grow grain or even a good crop of hay in Greenland.  When we can do that again, then we will have reached a historically normal climate. 
      So again I ask, "should we panic?"  No, we should be rejoicing because the Mini-Ice Age is ending.  I'm sure that the people at the end of the last major Ice Age didn't panic and get despondent when things warmed up.  I think that they were darned happy about it. 
      If it gets warm enough to grow grain in Greenland again, what would we be able to grow up here in Minnesota?  Right now it might be a good idea to invest in some land in Greenland.