What makes this winter in northern hemisphere so exceptional? “The two patterns of extreme weather in the UK and the east coast of the US are linked by shifts in the polar jet stream,” explains atmospheric scientist Jonathan Meagher who works as a senior analyst for Allianz Re.
“The deflection of the jet over North America has caused record low temperatures as far south as Texas and Florida. This in turn has supplied the energy for the series of strong storms over the North Atlantic that have impacted the UK over the winter.”
It is not only the United Kingdom that has been hit; at times much of the continental European coastline was affected. Further east, over the Mediterranean Sea, low pressure systems developed and pressed moist air against the Alps resulting in major floods in Italy, record snow levels in the mountains and freezing rain that paralyzed Slovenia.
The losses are only slowly becoming visible. In North America “the impact of cold weather and snowfall was most evident in travel delays, power outages, and general disruption to economic output. Initial estimate has put the cost at $5 billon,” says Meagher.
As for the UK, so far there have been no large insured losses reported yet. “However, if this weather pattern continues, river levels are likely to also increase and with that the likelihood of a major flood event,” said Meagher on a day (Feb. 12th) that the Met office later upgraded the UK weather warning again.
While winter weather is devastating large parts of the northern hemisphere, on the other side of the world Australia is again facing record heat waves. In what has become almost an annual event, massive bush fires are threatening the fringes of another major city, Melbourne this time. In fact, 2013 was the hottest year since records began in 1910.
‘‘These record high temperatures for Australia in 2013 cannot be explained by natural variability alone," David Karoly, a scientist at the University of Melbourne, told The Sydney Morning Herald. "This event could not have happened without increasing greenhouse gases, without climate change."