Last year’s cold winter sparked a huge resurgence into the global warming debate. If the earth is warming, why did we have a cold winter?
We’ve been in a “Solar Minimum” since about 2006, a long period with virtually no solar activity. I’ve been writing about this for quite some time in these pages as you’ll see from these links. Much of the hysteria over 2012 stems from the fact that we were due for a Solar Maximum period in 2012 which could create chaos in communication systems and electrical grids, but the extended minimum period, which ended just this year, suggests that we won’t hit the Solar Maximum period now until at least 2014.
Researchers in the UK have now identified a link between low sunspot activity and atmospheric conditions on Earth. This year’s winter, according to Professor Mike Lockwood, was the coldest in 160 years. He attributes the connection to a phenomenon called “blocking” which involvles the movement of the jet stream of the northern hemisphere.
“If you haven’t got blocking, then the jet stream brings the mild, wet westerly winds to give us the weather we are famous for.”
But, he added, if the jet stream is “blocked”, and pushed further northwards, then cold, dry winds from the east flow over Europe, resulting in a sharp fall in temperatures.
“This… ‘blocking’ does seem to be one of the things that can be modulated by solar activity,” he said.
Recent studies suggest that when solar activity is low, “blocking” events move eastwards from above north-eastern North America towards Europe, and become more stable.
A prolonged “blocking” during the most recent winter was responsible for the long spell of freezing conditions that gripped Europe.
Written observations from the period of the Maunder Minimum referred to the wind coming from the east during particularly cold winters, which strengthened the team’s “blocking” hypothesis.
The way in which solar activity affects the behaviour of blocking episodes is linked to the amount of ultraviolet (UV) emissions being produced by the Sun.
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