THIS past week has seen an unprecedented meeting of meteorological and climate experts at The Met Office to discuss recent “unusual” weather patterns affecting the UK over the past few years.
The experts emerged to announce, to much hand-wringing, that we can expect ten years of summer downpours.
But has the weather really been that bad?
And is it that strange after all?
There is no doubt the weather of the last six years or so has provided the layman with much to talk about, let alone the experts.
There were the downpours at last year’s Isle of Wight festival which saw revellers swamped in a sea of mud.
Not one but two Red Arrows performances in Southampton were cancelled for two major cruise events last year due to lashing rain and gales.
Southampton scrapped its Mela festival last year and even the traditional Netley Marsh steam fair got rained off.
In October, heavy rain and a high tide caused floods of up to 2ft feet deep on Southampton’s busiest roads, Mountbatten Way and Millbrook Road West.
Hampshire farmers spoke of their despair at devastating crop losses.
It could be argued that the exceptional summer floods of 2007 were the point at which things seemed to get a little out of kilter.
Since then we have had a run of relatively poor summers. Even the ones which weren’t flood-ridden have hardly been wall-to-wall sunshine.
At the other extreme, the winter season seems to have returned to our shores with a vengeance, with the coldest winter for 15 years in 2008/9 followed by the coldest winter for 30 years in 2009/10.
Legendary And while neither of these winters really rivalled the legendary ones of 1963 or 1947, December 2010 proved to be the coldest month in more than 100 years, and was a genuinely severe winter month.
Last spring we were in severe drought conditions following three dry winters on the trot, but despite this 2012 went on to be the wettest year on record in the UK (although those records have only been kept since 1910, and there were undoubtedly wetter years in England and Wales in the 1800s).
The last few months have provided us with another cold winter followed by the coldest spring for 50 years. So should we or the experts really be surprised by what has happened? Is it really that unusual? The answer to the first question is: not really.
The weather of the UK is always variable, because we are particularly at the mercy of the jet stream, which carries weather systems across the Atlantic towards our shores, and that variablilty in the jet stream can range from month to month, season to season and even over periods of tens of years.
For much of the period from 1988 to 2007, the jet stream pattern was strong and often running to the north of the UK.
This meant that our winters were often stormy due to the strength of the jet stream and mild due to its position north of the UK. Even when the jet stream flow did weaken in the summer, its average position to our north often allowed high pressure to dominate our summers and bring a good deal of fine weather. At the time, much of this warmer weather was put down to global warming and climate change.
In reality there was far more natural variation involved than was given credit. There are various periodic oceanic warming and cooling cycles which heavily influence the strength and position of the the jet stream, and it was only a matter of time before these changed, because they always have changed periodically – and always will.
In more recent times, the jet stream has been far weaker and much more meandering in its pattern, often flowing to the south of the UK. In winter, this makes it far easier for bitterly cold and snow-laden Arctic air to flood into the UK from the east, while in summer it can force rain-bearing low-pressure systems straight across the UK, rather than keeping them far to the north, as used to happen more often in the 1990s.
There are a number of culprits being blamed for this change of the jet stream pattern, ranging from the increased summer melting of sea ice to man-made global warming, to the oceanic pattern and also the fact that we are entering a solar minimum, with far fewer sun spots.
The latter is especially interesting in view of recent research showing a link between these periods and a greatly increased chance of bitter winters to the UK and Europe.
The Met Office summit, which looked at improving understanding of potential drivers of some of the unusual seasons, unsurprisingly concluded all these factors, and a few others besides, are affecting the situation to a greater or lesser extent.
A total of 25 weather and climate delegates including representatives from the Universities of Exeter, Leeds, Oxford, Reading, Imperial College London as well as the Met Office warned that because these cycles operate on cycles of a decade or more, we could experience soggy summers for “years to come.”
Our knowledge of our weather is increasing all the time but is far from complete, and so our ability to predict events will slowly change with time.
Perhaps our own expectation of what our weather can do needs to change as well. Long, hot, dry summers in the UK are an exception, not the rule, no matter how much some might wish it otherwise. In winter, the long succession of mild and quite stormy winters and autumns in the 1990s were an anomaly and did not reflect the fact that cold and snow are normal winter occurrences in the UK. In that respect our winters have really just returned to what was nearer the norm for much of the last 100 years or so.