June 20, 2007
Last autumn-winter season was Europe's WARMEST FOR MORE THAN 700 YEARS. The last time Europeans saw temperatures similar to those of the autumn and winter of 2006-07, they were eating strawberries at Christmas in 1289. European climate measurements and temperature records stretch back several hundred years to 1659. Estimating historical temperatures beyond then involves scrutinising contemporary documents and diaries. Separately the temperatures experienced during autumn 2006 and winter 2007 are likely to have been the warmest in 500 years. But the sequential combination of two such warm seasons is a still RARER event – probably the first since 1289. In that year, people in western and central Europe wrote accounts of what they viewed as EXTREMELY UNUSUAL events. "Documents report for instance that strawberries were eaten at Christmas, and the [vineyards] produced leaves, stock and even blossoms in the middle of January, and in Vienna fruit trees were flowering like in May. This was really extreme, so maybe it can be compared to today in western and central Europe." Similar UNUSUAL events have also been noticed in this recent warm period. For instance, hazel trees and snowdrops in Germany blossomed a full 30 days earlier than at any time in the last 50 years in spring 2007. And in 2006, horse chestnut trees in Switzerland blossomed twice instead of their usual once. "This is really an EXCEPTIONALLY RARE event." The 1289 temperatures may have been caused by a large volcanic eruption in the tropics. The warm autumn and winter in 2006-07 were due to warm air moving up from the Atlantic off the coast of North Africa.