There is compelling evidence that much of the extreme weather we have seen in the Northern Hemisphere over the last decade is strongly linked to the non-linear warming of the Arctic.
For a start, you may have heard that something about the Jet Stream behaving strangely. But what is the Jet Stream exactly, and how is it linked to the Arctic and to our weather systems? Here a US meteorologist Jennifer Francis explains this in more detail.
http://e360.yale.edu/feature/linking_we ... ctic/2501/
Explaining the physical origin of the Jet Stream, she goes on to provide an explanation of the changes that are resulting from the Arctic warming faster than the rest of the planet.
Over the last 15 years, the loss of snow and ice has accelerated in the Arctic while the global temperature has not increased very much. This observation has been siezed upon by climate change skeptics as evidence that human emissions of greenhouse gases are not the main driver of climate change, as carbon dioxide, methane and all the important sources of warming have increased dramatically over the past 15 years.
But there has to be something responsible for the ongoing Arctic melting! If global warming, caused by human activity, was what set the Arctic into meltdown, then it is to be expected that global warming should proceed with Arctic melt. And despite the slowdown in global temperature rise, we seem to be seeing escalating climate impacts around the globe. Climate change is clearly not going away!
The important point is that the global temperature does not necessarily need to be increasing for the Arctic to melt.
For one thing, the melting of ice is influenced greatly by a positive feedback, albedo loss. For every bit of ice lost, the Arctic absorbs more heat than it did previously as reflective white ice is replaced by heat absorbing dark blue ocean. This effect comes on top of the warming effect that caused the initial melt.
So even if there has been a pause in global warming, Arctic warming can be expected to advance nonetheless.
In addition, another driver of Arctic warming is the the transport of heat into the Arctic by the oceans. This heat absorption has continued over the past 15 years, according to the UN Weather Agency http://www.planetark.org/enviro-news/item/71279, even though global surface temperatures have not risen very much in the same period. It is known that the oceans absorb most of the heat from the greenhouse effect initially, only to release it later.
The weather disruption we tend to see is not what we would expect from global warming. If that were the case, droughts and floods would be more extreme in terms of their intensity. We have seen droughts, in the US, the Middle East and even in Russia, that did not always break temperature records but were very damaging because of the unrelentingly long period of time over which they struck. How the Jet Stream disruption we have seen can induce weather patterns of this type is explained by Jennifer Francis in the link above.
In conclusion, there is ample evidence to suggest that the key to the climate change we have experienced in recent years is the Arctic, over global warming.