While I never call myself a scientist, I do have a graduate degree in an earth-science and I can hold my own amongst the formulae and logic from which global warming forecasts are derived. Deniers who try to label themselves as "skeptics" simply aren't. They have no basis for their position and you have never met a greater skeptic than a scientist who requires proof for every conclusion and research into every hypothesis. So, by definition the scientists are skeptics and the deniers simply have their heads up their asses.
Now, something you will never see in Canada, (since the retirement of Dr. Arthur Carty and the abolition of the National Science Advisor position he held until 2008 by the flat-earther-in-chief, Stephen Harper), is scientific information coming from the head of government to bring the population up to speed on what's happening, using easily understandable terms. In the US, however, it gets treated as freely available information in a two minute explanation by the National Science Advisor to the President. (Hat tip Lorne).
Right, that's all good. I'm going to add to that since my discipline deals with the ocean.
As the majority of the globe warms, (which is exactly what it's been doing), particularly in the tropics and the sub-tropics, all the warm, buoyant air from that region rises, cools and then, after diverging at the edge of the stratosphere, falls. It comes down as cold, dry air. When there is rapid warming at the equator, the air rises faster, cools and drys faster and comes crashing down like a lead weight as high pressure.
The forcing of that pressure moves the boundaries of the three hemispheric cells which make up the pressure regions of the Earth's atmosphere. In the Arctic, when winter brings less or no sunlight to warm the surface, the air becomes dense. As high pressure it also creates a surface forcing. The Polar cell in the Arctic pushes against the Ferrel cell in the mid-latitudes and a vortex is created aloft - the Polar Jet. In a perfect world, this would work its way around the globe at roughly the same latitude.
In an imperfect world the dense polar air pushes outward toward the equator over the frozen landmass. When the Hadley cell has more warm air than normal it squeezes poleward overriding the Ferrel cell, bending the Subtropical Jet and the Polar Jet starts to buckle ... badly. It's called a Rossby Wave, which was identified in the June, 1939, Journal of Marine Research*. So, this is neither a new nor confounding concept.
Add to all this the fact that the Arctic air temperature is a full 2°C warmer now than it was in 1960. In the eastern Arctic water temperatures, as a result of rapid melting of sea ice, were a full 5°C warmer by the end of summer 2013 than they were over a 30 year average measured from 1977 - 2006. That's huge on any atmospheric/oceanographic scale because salt water requires a great deal of absorbed solar energy to produce a rise in temperature and once it's there it retains it for longer than almost any other substance on Earth. That tells us that the Arctic got warmer, a lot warmer, and it's going to retain much of what it absorbed due to the high specific heat capacity of the Arctic Ocean. (Aug 2013 sea surface temps. Redder is warmer than 30 year average; Bluer is colder than 30 average)
What this specific heat capacity does is upset the feedback loop of atmospheric circulation. Instead of dense, cold, Arctic air spreading evenly over the pole, the eastern side warmed the air, expanding it and making it more buoyant. This is the same as inflating a balloon in a bucket of water. Eventually warmer eastern Arctic air spreading forced the dense air over the ice cap onto the colder landmass of the western hemisphere.
In simplistic terms, the atmospheric centre of the Arctic air mass, (call it the atmospheric north pole), was shoved off the ice cap and the centre (which should be near the North Pole) moved over northern Canada. The entire air mass moved south and the characteristics of that entire air mass, moved with it, south. While southern Canada and the continental US were undergoing the coldest temperatures ever remembered, Siberia, one of the coldest winter environments in the northern hemisphere, was recording temperatures above freezing with rain.
Is this a result of global warming? A single event cannot be attributed to climate change. However, what happened so far this winter is directly attributable to the conditions I have just described above and all of those things combined suggest this is just another of a long string of events which are symptomatic of increased warming of the planet. It is another extreme weather event which was forecast in warnings issued over a decade ago and modeled in 2006 by the US National Center for Atmospheric Research.
Here's the kicker: It's happening more quickly than forecast (not by much on the Big Bang scale) and with each advance of changing conditions it accelerates the process exponentially. In short, get used to more flooding, more ice storms, more droughts and get used to them now. They are not going away. If Stephen Harper thought changing to a "green" energy policy was too expensive, wait until he sees what it's going to cost to deal with the damage that's about to come because he didn't listen. And yes, your property insurance premiums are going to skyrocket. And whenever I say or write that, I think of this old ad.
Local Policy: Alright then, whenever I write something about this subject the comments section gets invaded by an army of right-wing, flying monkeys who learned their science from unscrewing beer-bottle caps. Most have never opened a textbook and wouldn't recognize basic algebra, much less solve a problem. So, be aware:
1. This is not a free-speech zone. If all you intend to do is fling insults, you'll be deleted and permanently banned;
2. If you are making an opposing or alternative argument, support it with evidence. Failure to do so will bring about the actions of item 1;
3. If, as has happened twice now, the disciples of some half-educated, over-paid pundit come in en mass, I will close comments on this post.
* The reference, I am told, has been removed from some Canadian government departmental libraries. I have my own copy.