Extreme UK Weather Patterns Could Be A Direct Result Of Warming In The Arctic

In the UK our weather has a well-earned reputation for being miserable (think rain, rain and more rain), but it seems currently our meteorological misfortune is a little out of character.

This is after a new study found weather extremes in Britain could actually be a result of warming trends in the Arctic circle, leaving us with colder winters and wetter summers.

Temperatures in the Arctic have averaged at least twice the global warming rate over the past two decades, and the team of climate scientists wanted to know if there was a correlation between this and extreme weather conditions in the UK.

Professor Edward Hanna from the University of Lincoln, said: “Arctic warming may be driving recent North Atlantic atmospheric circulation changes that are linked to some of the most extreme weather events in the UK over the last decade.”

The team at the University of Lincoln examined archives of historic weather data and compared the timings of extreme events, for example, heavy snow, with the position of the North Atlantic polar atmospheric jet stream.

The jet stream is important in understanding our weather, because as a giant current of air that flows eastward over mid-latitude regions around the globe, it influences the conditions we experience on the ground.

As you would expect with a giant body of air, it ebbs and flows, marked as positive and negative spikes on a tool known as the North Atlantic Oscillation (NAO) index.

When the team investigated, the NAO showed that the exceptionally wet UK summers of 2007 and 2012 had notably negative readings. As did the cold winters of 2009/10 and 2010/11.

While the mild, wet and stormy winters of 2013/14 and 2015/16 showed pronounced positive spikes on the tool.

Not only do positive and negative spikes play a part, but so does the jet’s so-called ‘waviness’ (basically, the more wavy, the weaker the jet stream is).

Professor Hanna said: “Of course, weather is naturally chaotic, and extremes are a normal part of our highly variable UK climate, but globally there has recently been an increase in the incidence of high temperature and heavy precipitation extremes.”

And although an Arctic connection may not occur each year, it definitely plays a part.

Professor Hanna explained that while part of the uneven seasonal changes might be due to natural random fluctuations in atmospheric circulation, the statistically highly unusual clustering of extreme values may be influenced by longer-term external factors. 

“This includes possible influences from the tropical oceans and solar energy changes as well as the extreme warming that has recently occurred in the Arctic,” he added.