I’ve just watched BBC Horizon’s latest investigation of extreme UK weather entitled ‘What’s Wrong with our Weather?’ presented by physicist Dr Helen Czerski and meteorologist John Hammond. Whilst it had the usual format based around a scientific ‘whodunnit’, the climate change elephant in the room eventually made its presence felt and skewed proceedings rather predictably thereafter.
The program talks about the ‘very unusual’ extreme weather which the UK has been experiencing in recent decades and sets out to explore what might be causing that extreme weather. Firstly, it investigates the very wet, stormy winter we had in 2013/14, the “wettest on record” so the narrator says – no mention that past winter rainfall has been just as, if not more extreme, but we’ll let that pass because, technically, Dec/Jan/Feb total rainfall was a record according to the UK rainfall record going back to 1910 and the England & Wales Precipitation record going back to 1766.
The lack of Atlantic hurricanes in 2013 is postulated as a possible causative factor. Basically, hurricanes leave colder water tracks in their wake which persist for weeks and, so the theory goes, because there were so few of them, tropical waters were unusually warm, which might exacerbate the temperature difference between colder polar air and warmer tropical air pushing up from the south, which would ‘supercharge’ the Jet Stream. However, the effect was deemed to be too small.
The Jet Stream in 2013/14 was, according to the program, about twice its normal speed (300mph against 100-150mph) over the Northern Atlantic and this is what caused the severe run of storms which hit the UK. John Hammond explains that this superfast Jet Stream came “straight across the Atlantic” to hit UK shores.
The reinforcing effect of the stratospheric Quasi Biennial Oscillation is looked at but dismissed as a major influence on what was driving the Jet Stream during 2013/14.
So then we get to the ‘third explanation’ which involves flooding and heavy rains in Indonesia having a knock on effect on the Pacific Jet Stream hitting the US west coast, translating into the big dip in the Jet Stream over Northern and Eastern US which gave this region its now famous ‘polar vortex’ extreme cold winter. Dame Julia Slingo appears to favour this explanation. I quote: “What happens in Indonesia affects profoundly the weather patterns around the world”. Quite why this region should be specially marked out for such greatness, I’m not sure, but then I guess, it’s ‘very complicated’. Anyway, these Indonesian rains diverted the Pacific Jet Stream far north as it headed for America, then it dipped far south allowing cold polar air to dominate over the US continent and, according to this theory, where the cold polar air met the much warmer air of the mid Atlantic, the steep temperature gradient resulted in the increased velocity of the North Atlantic Jet Stream which then slammed into the UK.
I’m sure there are aspects to this explanation which are correct, but I’m equally sure it’s just a part of a much bigger puzzle. For instance, what caused the flooding in Indonesia? Was the steep temperature gradient between the polar and sub tropical air masses the sole or even primary cause of the acceleration of the North Atlantic Jet Stream? But keep this point in mind: the superfast Jet Stream of 2013/14 is blamed in part on the stark temperature difference created by the path of the Jet Stream dipping way south over the US to bring very cold polar air into contact with much warmer air.
To be fair, the program then goes on to say that the flooding in Indonesia and the QBO were just contributing factors in a whole host of things which resulted in the weather patterns which we witnessed in the US and the UK last winter. But then this is the precursor to introducing the biggie: ‘CLIMATE CHANGE’ (TM), whereupon things get scary, with images of rapidly disappearing snow and ice in the Arctic. But this isn’t just any climate change, it’s computer modeled climate change. Cue Helen Czerski sitting on a beach, extolling the magnificence of climate models:
“They incorporate the best of our current understanding. They represent the collective work of thousands of scientists. They’re an amazing achievement, and when they get as good as they are now it’s possible to use them like a sort of flight simulator for a planet. It’s an amazing tool to have.”
Er, yes, we’ll just forget the fact that they have all failed comprehensively to model the actual climate shall we? The fact that they couldn’t predict the 17 year temperature hiatus or the huge increase in Antarctic sea-ice. Slingo is even more gushing in her praise. She says:
“I think today the incredible complexity and power and skill of these models that we use . . . . they are one of the great achievements of modern science and you realise that we are entering I think a Golden Age for climate science. And it’s good that we are because we have some really really big questions to answer for the world.”
No doubt in Slingo’s mind then that computer generated virtual reality will show us the way forward to tackling man-made climate change. After all, 20 trillion calculations per second can’t be wrong – can they? According to the program, the climate models predict more extreme weather as the climate warms and Czerski tells us that ‘basic physics’ predicts that intense rainfall events will be more frequent in a warming world.
Now here’s where it gets interesting (or boring, depending on your viewpoint): Arctic Amplification (accelerated warming at the North Pole) and how it had a part to play in our recent much colder winters. It’s quite alarmingly simple really: global warming melts the sea ice at the Pole, which then reduces the albedo of the surface (ice reflects more of the Sun’s energy than open ocean), which then acts as a positive feedback to produce more warming and melting of sea ice and, hey presto!, suddenly all the ice is gone. To reinforce the idea, we are told that Arctic sea-ice has been declining at an alarming rate, forgetting to mention of course the recent partial recovery.
But here’s the gist: warmer pole = less temperature gradient between Arctic and sub tropical air masses = slower Jet Stream = less energetic Jet Stream = more meandering Jet Stream – analogous with a river forming large meanders as it loses momentum on the flat flood plain. So far, so good. Hence, we get the ‘stuck’ weather patterns which we have been witnessing in recent years and the ‘loopiness’ of the Jet Stream which has allowed cold Arctic or Siberian air masses to dominate our winter weather for weeks on end. To be fair once again, the program notes that there is not enough data to conclusively link Arctic amplification with extreme weather.
We are then treated to a few ‘alternative’ explanations for extreme weather, notably sudden stratospheric warming (SSW) affecting the troposphere and Jet Stream below, with no mention at all of what might cause these SSWs in the first place. And then, once only in the entire program, almost as an aside, mention of the almost taboo phrase of ‘solar activity’. There, you heard it (or missed it, as the case may be), that was it, near the end of the program, thence no more to be repeated and certainly not to be expanded upon. Perish the very thought that there might be an entirely obvious, logical and natural explanation for recent extreme weather events. Perish the ludicrous idea that a giant ball of superheated, extremely energetic plasma 109 times the diameter of earth and just 93 million miles away, could in any significant way affect our weather patterns or climate. I mean, a few parts per million of fossil fuel CO2 is far, far more likely to have an impact; it’s blindingly obvious. Which brings me finally to what Hammond has to say.
For Hammond closes the program by correctly identifying the Jet Stream as being the most obvious and immediate ’cause’ of the patterns of extreme weather which the UK has been experiencing recently. But what he says is as follows:
“For me the strongest signal to emerge as we struggle to understand the recent extreme weather is the idea that the jet stream can become ‘stuck’ in certain configurations. At one end of the spectrum a very straight, fast jet stream which brought the storms of last winter. At the other end of the spectrum a much slower, meandering Jet Stream which has brought the recent run of particularly cold winters”.
Get that? Fast, straight Jet Stream caused the winter storms? Obviously then, by this logic, Arctic amplification, aka global warming, could not have been involved in 2013/14 winter flooding, because that tends to produce a slower Jet. But, wasn’t the Jet Stream of 2013/14 also meandering? Didn’t it track abnormally far north on the US west coast, then dip far south over the country to allow the formation of the Polar Vortex? So, it might have been very fast moving – at least over the North Atlantic section – but it most definitely was not in a straight configuration.
BBC News, in Feb 2014, reporting on the very same Arctic amplification theory outlined in their flagship Horizon program, coupled with the wet stormy weather, says that accelerated warming in the Arctic may be making the Jet Stream much ‘wavier’ and, I quote:
“The meandering jet stream has accounted for the recent stormy weather over the UK and the bitter winter weather in the US Mid-West remaining longer than it otherwise would have.”
So the BBC appears to be a little confused on this issue. Either the Jet Stream is slower moving and more ‘loopy’ or it’s faster moving and straighter. It can’t at once be more meandering and faster? Can it? Well, yes, that’s what happened in winter 2013/14, but it doesn’t fit the theories of man-made global warming influencing extreme weather via the Jet Stream which the BBC and the Met Office would obviously prefer to promote in their programming. To explain reality, you have to get away from the ‘Golden Age’ climate models, away from AGW and venture into the world of solar physics, solar sunspot cycles, geomagnetism and upper atmospheric physics and chemistry. Therein lie the clues to explaining the actual behaviour of the Jet Stream, but that’s far too rigorously scientific for the BBC I guess.