This seems to have been another one of those years where you could attribute a number extreme weather events to the forces of nature unleashed by climate change. We have seen flash floods in the UK, extreme floods in Pakistan, drought and wildfires in Russia and now the early onset of winter in Europe brings with it near record low temperatures for the time of year.
Invariably climate change deniers will point to the arrival of winter in Europe as a sign that emissions of greenhouse gases cannot possibly be causing the world to warm. Others, amongst whom I count myself, would say that the weather we have been experiencing is a sign of the increasing instability we can expect as atmospheric concentrations of carbon dioxide and other temperature forcing emissions continue to rise.
Early Winter Temperatures - Europe 2010
Reproduced (without permission) from Weather Underground (wunderground.com)
Also visit the site for animated maps of the Jet stream
Whatever point of view you choose to adopt, there is still insufficient knowledge for scientists to explain with conviction the cause of such unseasonally low temperatures. Options that have been identified include:
- Weakening of the Gulf Stream which normally brings warm waters from the tropics, sufficient to compensate for cold weather coming from the Arctic. This has been discussed by many authors - see for example, an article published by the BBC in 2005: Ocean changes will cool Europe and one by NASA appearing on it's Ocean Motion website.
- A loop in the North Atlantic Jet Stream which circulates at high altitude (typically 10,000 meters) has pulled high pressure, cold Arctic air much further south than normal. To give climate change deniers their due, such a change in the weather's footprint could be influenced by solar activity, rather than human induced climate change.
Paradoxically, this recent winter weather may be a consequence of global warming that appears to be responsible for the steady increase in the amounts of ice lost from Greenland and the Arctic icecap. The fresh melt water pouring into the sea has reduced salinity levels in the Northern Atlantic. This cold water sinks more slowly, which is in turn has slowed down the engine that drives the Gulf Stream.
The Ocean Circulation System
Adapted from the IPCC Third Assessment Report, 2001
Schematic of the World's ocean circulation system which includes north-south routes in each of the major oceans that join with the Antarctic circumpolar circuit. This system contributes substantially to the transport and distribution of heat across the planet, e.g. flow of the Gulf Stream towards the North Pole warms Europe by up to 10°C.
Availability of Fuel
It remains to be seen whether extreme winters will become the norm in Europe. More worryingly is the fact that the inextricable draw down of natural resources coupled with growing demand by the developing nations, means member states are getting closer to a point where they will find it difficult to source the fuel needed to isolate their populations from the full effects of harsh weather. For example, here in the UK a whole generation has grown-up accustomed 
to the idea that gas central heating boilers can always be turned on when it is cold. In reality, we are increasingly reliant on imports of gas from Norway (Ormen Lange), Russia (Siberia) and the Middle East (shipments of liquefied natural gas). Most of these supplies will be exhausted within 15 years, notwithstanding the fact that a growing percentage of our population is already struggling to find the money to pay their heating bills.
