The Next Ice Age

There have been more than twenty known ice ages in the history of our planet and much has been written about their effects that we can see today. But have you ever wondered what changes to the present geography of earth the next ice age will bring? To explore this question we must, of course, put global warming aside for the moment and assume that there will be another ice age in the future.

Basically, the continents and islands of the world are built up by tectonic collisions and volcanic activity which is then shaped by primary and secondary glaciation during the ice ages. A glacier that advances southward during ice ages is a mountain of ice maybe two km thick that spans an area hundreds of kilometers wide. As I have pointed out in my discussions of glaciation, much of the lasting effect on the landscape of glaciers is from secondary, rather than primary, glaciation. That is at the end of ice ages as the climate warms, massive bergs of ice break off the melting glacier and impact and slide over the land below.

It is my feeling that the place which will be most affected by the next ice age will be Europe. On http://www.maps.google.com/ we can see the vast shallow area of water around northwestern Europe. It is also easy to see how the continents have split apart due to the volcanic spreading of the Mid-Atlantic Ridge. This vast wedge-shaped area of shallow water can be seen to have split off the area of continental shelf around Newfoundland in eastern Canada.

This area of shallow water in northwestern Europe was almost certainly once all land which has been eroded away to below the water level by glaciers in successive ice ages. This includes the North, Baltic and, Irish Seas also the English Channel and far out into the Atlantic Ocean. You can see a shallow area to the northwest of Ireland and about the size of that country. This must have once been an island about the size of Ireland that is now gone. Denmark is all lowland that would have been eroded away by glaciers except that it was shielded by the bulk of the Norwegian Mountains.

There are two significant curves that we can see on the map of western Europe where glaciers have carved away at the land in ice age after ice age. the west coast of France along the Bay of Biscay has been gradually carved away although it has been shielded by the mountains on the peninsula known as Brittany. The other curve is from the northwest corner of the Netherlands to Calais at the Strait of Dover. We can expect that the next ice age will continue this process.

In my posting, "New Discoveries In Northern Europe" on this blog, I explained why Britain must have had ice crossing it from both the northwest, where it would usually come from, and also the northeast, due to ice piling up against and being deflected by the Norwegian Mountains. The ice from the northwest should be far greater in volume but it actually is not, because Britain is in the "glacial shadow" of Iceland.

The main route across England of the ice that comes from the northwest during ice ages is through the North Channel, which separates Scotland from Northern Ireland. The main route of ice then follows what I will call the "Severn Route". There is are two bays just southwest of Liverpool with Birkenhead between them. This represents the crossing of the main bulk of glacial ice onto land from the shallow sea, which freezes during the ice ages.

The ice goes around the Welsh mountains and is diverted southward by the southern portion of the Pennine Mountains. The ice continues southward through what is now called the "Severn Vale" and is occupied by the present-day Severn River. The flow of ice continues to the Bristol Channel.

The mountains of Wales are the primary factor preventing the ice from taking a more direct route southward. The Severn Vale is much too vast to have been carved by water alone and there is no evidence that it is a fissure in the earth's crust or anything like that. Furthermore, I have shown in my posting "New Discoveries In The Forest Of Dean" on this blog that the ice from the Vale produced a glacial impact crater at Cinderford.

My hypothesis is that the Severn Vale has not yet been eroded enough by the ice in ice ages to be below water but that may well change with the next ice age. Wales will become an island at that time and there will be a channel of the sea from what is now Liverpool to Bristol.

The only reason that this has not yet happened, that the Severn Vale is still dry land is the Isle of Man. The main thrust of the glacial ice comes through the break in the mountains and high ground that is the North Channel. But instead of going straight toward Liverpool, the majority of the ice is diverted southward by the mountainous Isle of Man.

Only a portion of the main glacial thrust goes around the Isle to the north and goes through the Severn Route. Liverpool and the Severn Vale are in the glacial shadow of the Isle of Man just as all of Britain is in the glacial shadow of Iceland.

The Isle of Man itself is being eroded away by glaciation in successive ice ages. When it is gone, the main thrust of ice will go through what then may be called the "Severn Channel" and it will get wider and wider. Eventually Wales, as seen from England, will be but a line of mountains on the horizon.