Europe Warmer Than Expected From Climate Change
Europe's balmy autumn of 2006 broke all historical temperature records and confounded predictions by climate change models. From the northern slopes of the Alps to southern Norway and from Belgium in the west to Poland in the east, the months of September to November averaged 3 degrees Celsius hotter than normal temperatures for 1961 to 1990.
The season also broke records kept for centuries. Average temperatures in 2006 exceeded the warmest autumn since 1706 in the Netherlands by 1.6 °C, and beat records kept since 1659 in central England by 0.8 °C. From Switzerland to southeastern England, temperatures over the three months sat more than a degree warmer than any in the last 500 years. If global warming was not underway, the chances of having weather like this would be only once in 10,000 years or more.
Even with climatic warming taken into account, the fall of 2006 still stands as an extremely rare event. For most of Europe, temperatures that tepid could be expected only once every 200 years. In northern Germany, the odds of an autumn as warm as 2006 sit at once in 1,000 years.
Either Europe will not see winter delayed like that again for several hundred years. Or climate change models lack some critical factors, in which case European autumns are heating up faster than the models predict.
A combination of sunshine, tepid seas and southerly winds sustained the seemingly endless summer. It began with an exceptionally sunny September and with the North Sea's surface temperatures raised 2 °C above normal after a searing-hot July. The main influence, though, was prevailing winds blowing from the south that pushed warm air northward. The winds arose from a low-pressure air mass sitting over the Atlantic Ocean.
G.J. van Oldenborgh. 2007. How unusual was autumn 2006 in Europe? Climate of the Past Discussion. 3: 811-837.