If we look at the timeline for past Ice Ages are actually quite common, whereas Interglacial Periods (like the one we are currently living in) are quite rare. You will also note that Interglacial Periods usually don't last that long. Mankind has managed to flourish during the last 14,000 years because of an unusually long modern Interglacial Period.
As you can see our current Interglacial Period has lasted approx. 14,000 years, and compared to past Interglacial Periods they usually don't last very long and tend to have a sharp peak - the last 14,000 years however have been relatively stable, with mini ice ages roughly every 400 years (averaging 407 years according to scientific estimates).
One of the biggest factors for the rise and fall of mini ice ages is something we often take for granted: the Sun. Sunspots expel heat (solar irradiation) in large amounts and go through cycles that last 8 to 14 years (averaging 11 years per solar cycle). However once every 407 years we get a time period where the solar cycles dwindle to almost nothing, expelling less heat. This in turn effects the temperatures on Earth.
During that time we have a Maunder Minimum - a period of time where there is a dramatic drop in sunspot activity and less heat coming from the sun, which in turn results in the Little Ice Age (a time period after the Medieval Warming Period). During the Little Ice Age the Thames River in London, England froze over each year, record cold temperatures were recorded, huge snowfalls were recorded in North America and northern Europe, glaciers across the globe grew dramatically, and of course glaciers on both the north and south poles grew significantly.
In Canada we got record cold temperatures in 2013, 2014 and 2015 - including the coldest spring since the 1960s. Judging by the reduction in heat coming from the sun we will be expecting a New Maunder Minimum starting in either 2015 or 2026.
To be continued...