"Global warming" has always been an unfortunate label to what, globally, is climate change. Scientists (all pesky, "alarmist" 95% of them) have always predicted that, both short term and long term, some regions will become frigid while others will fry. Ditto with precip - new floods and deserts.
When we, in MI, experienced our record cold and snowy winter three years ago, the term "polar vortex" found its way into our vocabulary, further discrediting "warming", but the cause was, in fact, indirect warming.
Both the north and south pole have a permanent, low pressure cyclone (polar vortex) hovering above them. The strength of a polar vortex is determined by the comparative difference in temperature between it and the equator. The larger that temperature difference is, the stronger the vortex, with "strength" meaning how malleable it is by other air currents. When it's strong, it tends to stay put. When it's weak, it can be squeezed into fingers or new clumps which can dip unusually far south.
As the Arctic ice mass melts and its air warms, its once-strong winter temperature differentiation lessens. Hence, its vortex is weaker, and depending on where it's bullied into pressing southward, various parts of the globe will now likely take turns suffering record cruel winters.
Whether we wish to excuse ourselves from the equation or not is probably moot at this point, as is whatever caused the ocean currents to slow to a standstill once before, causing a thousand year freeze (and searing heat and drought in some regions), because the slowing of our ocean currents is again underway. And even the countries most dedicated to reducing their carbon emissions are doing nothing to curtail population growth.
What, for me, is most memorable about Al Gore's excellent documentary, An Inconvenient Truth, is his chart depicting the speed at which, and the extent to which current climate trends are exploding - all vastly larger values than in previous, natural cycles.
