Lately with the extreme storms and cold snap in the northern hemisphere there are claims circulating worldwide that we are now entering a period of global cooling.
Over the coming months, just like the leaked e-mails from East Anglia University in the lead up to the Copenhagen Climate Change Summit in December, these latest weather anomalies will most likely be reported as broadly by those wishing to cast the shadow of doubt on the broadly established science of an overall upward trend in global average temperatures as they can, to facilitate several outcomes that I will talk about shortly.
First though let's get one thing out early. Weather on any given day, week, or month, or even year, does not for those who understand overall long term warming, mean any more than what should be referred to, as "weather variability' or in terms of the general vernacular "climate change'. Weather has, and always will be, wildly erratic. As the world experiences shifts in the circulation of air currents due to areas of extreme change such as those occurring in the rapidly heating Arctic and Antarctic, weather anomalies both extreme and or just unusual, will be experienced. Some areas may experience increased drought, some increased heavy rainfall causing floods, and some, as presently being encountered in the northern hemisphere, extreme cold snaps.
Let's think of it like that of a deepfreeze refrigerator door being left open. The air outside the deepfreeze is warm and rises; the air inside the freezer is cold, and unlike hot air rising, it drops. As the ice thaws, more cold air becomes available and if you could see it, you would see the cold air as it drops pushing more hot air upwards Circulation! As I said I am no climate scientist or meteorologist, however we do know the Arctic and Antarctic freezer doors have been left open.
In Australia where I live, in the spring and summer months in years gone by, it was almost monotonous to watch the evening weather forecast and see a High Pressure Zone sitting squarely in the Great Australian Bight off the shore of South Australia. It sat there for days, even weeks on end. This high pressure trough meant that each morning during those weeks and months in the early part of the day, an easterly wind bringing hot air from the Great Sandy Desert would blow through the eastern facing windows of our home in Western Australia. In the mid to late afternoon there would be what locally is called, the Fremantle Doctor, a sea breeze from the west bringing much welcomed relief on the hot summer days. The high in the Bight no longer remains stationary; in fact this year it has been rarely seen except as it moves quickly eastwards bringing "extreme weather' anomalies to the Eastern States of Australia. Yesterday by way of example January 11th 2010 saw Adelaide in South Australia experience 40 degrees C Melbourne today January 12th will have these temperatures to endure, while Adelaide will drop dramatically to 26 degrees C. - 14 degrees in one day. In Western Australia we have seen similar dramatic shifts from one day to the next, where in past years, you could expect as reliably as a Swiss watch, that spring would come on time and gradually warm up to summer when days on end you could expect similar temperatures. The Weather Man was always spot on with the forecast and now he hasn't a hope in hell of getting the 7 day forecast right!
So what we have is "weather variability' so what is causing it? We, the global population have left the freezer door open.