This winter (2007-2008) snow fall and snow cover has been at its greatest over North America, Siberia and China since 1966. And the Arctic ice sheet, which for so long has been all but doomed by modern climate models, has had a resurgence. Of course, this is just one winter and the next one could continue the warming trend of the last 2 decades. However there are now two big reasons why it could be possible that we are on the brink of a new ice age.
Firstly there is the global circulation of the ocean currents which goes something like this. At the poles the sinking cold water dives rapidly downwards for thousands of feet and drive a cold water current at the bottom of the ocean. Meanwhile as this cold water meets the tropics it warms and rises and gets driven north by surface winds, redistributing the heat. The more efficient this global ocean conveyor belt, the warmer the world. However as the the melting of the Greenland ice sheet breaks all new records a huge amount of fresh water is making its way into our oceans. This water is less salty and doesn't sink as efficiently, disrupting the circulation of the ocean currents, such as the gulf stream. As a consequence less heat is transferred north and we are all left reaching for our woolly hats and thermal pyjamas.
Okay, this process is quite well known now, and is just another theoretical model (although there have been signs recently of a slow down in the Gulf Stream bringing warm tropical air from the Gulf of Mexico to the North Atlantic. But, there is another factor in all of this which is getting climatologists and astronomers reaching for the medicine cabinet. Sun Spots.
Sun Spots are cooler patches on the surface of the sun, but they are magnetically very active and are associated with huge solar flares and coronal mass ejections. That is, a whole load of heat and energy being pumped out towards us and all the other planets in the solar system. However, sun spot activity is currently very low. The last time the sun was this inactive was back in the 500 years from the mid 1300's to the mid 1800's, commonly know as the little ice age. This global cooling of around 1-1.5 degrees Fahrenheit, caused livestock to die, crops to fail and widespread famine and gnashing of teeth around the world. London's River Thames would freeze regularly in the winters and little tykes would skate and chuck snowballs at each other, so it wasn't all bad.
So are we in for a cooler world, a new little ice age? Well who knows really. The global warming doom merchants are in the red corner, and the little ice age pessimists are in the blue corner. Who will be right? Only time will tell, but we will continue to get along with our lives in the normal way whatever nature throws at us. So get the sun block on in the summer, and two pairs of socks in the winter. It's being so cheerful that keeps us going!
Mark Boardman BSc dip.hyp is a leading author and expert on href="http://www.agloriousfuture.com">the world of weather For more information about href="http://www.agloriousfuture.com/snow.php">snow and ice, have a browse through these sites today.
