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Global warming making wet winters more likely

30 April 2014, by Alex Peel

Wet winters are now more likely in southern England than they would be without global warming.

Wind and rain

That's the conclusion of new research at the University of Oxford, which used spare capacity on thousands of volunteers' home computers to assess how greenhouse-gas emissions influence our weather.

The extra computer power allowed them to run tens of thousands of simulations of possible weather, both with and without the influence of man-made emissions.

Their findings suggest that what would have been a once in a century rainfall event, can now be considered a 1-in-80-year event. In other words, the risk of extreme rainfall in any given winter has risen by 25 per cent. Researchers say it is a modest, but statistically robust rise.

There was some variation in the models, depending on how the pattern of man-made warming was represented. In some, the likelihood of wet winters showed no change or even went down. But taken as whole, when run with man-made greenhouse gas emissions in the atmosphere, the models favour wetter winters.

'It will never be possible to say that any specific flood was caused by human-induced climate change'
Dr Friederike Otto,
University of Oxford

The news comes after much of the UK experienced its wettest winter on record in early 2014. As a string of ferocious storms barrelled into Southern England, many rivers across the region swelled to their highest-ever recorded levels. More than 5,000 homes and business were flooded.

Speaking in the House of Commons, Prime Minister David Cameron said he 'very much suspected' that the floods were linked to climate change. The comments sparked a fierce national debate over the issue.

'It will never be possible to say that any specific flood was caused by human-induced climate change,' says Dr Friederike Otto, one of the Oxford researchers involved with the project. 'We have shown, however, that the odds of getting an extremely wet winter are changing due to man-made climate change.'

'Past greenhouse gas emissions have 'loaded the weather dice' so the probability of the south of England experiencing extremely wet winters again has slightly increased.'

But she cautions against drawing direct conclusions from this about the risk of future flood damage.

'Total winter rainfall, although useful as a benchmark, is not the direct cause of flood damage, so we are working with partners, such as the Centre for Ecology & Hydrology, to explore the implications of our results for river flows, flooding and ultimately property damage,' she adds.


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Your comments

And yet the met office said that the rains were not linked to Global Warming (climate change) but to the Jet Stream.
The Jet Stream according to the Met Office was the reason for the hot summers across the continent a few years back and yet the global warmist about a month after said it was climate change.
The Jet stream changes out weather as it does all countries in the northern part of the northern hemisphere. We only have to look at the USA this winter Met Office said Jet Stream, yet a month after government said climate change.

Jon Nemo, Tumble, Llanelli
Wednesday, 30 April 2014 - 15:34

Those two explanations aren't mutually exclusive; it's not a matter of it either being climate change or the jet stream. It's as if one person said there was a lot of rain because of the jet stream, and another said no, it was because there were a lot of clouds in the sky with a lot of water in them. Which of them is right? In reality there's no contradiction. Likewise it might be that climate change is influencing the behaviour of the jet stream, so the two factors are linked.

Tom Marshall, Planet Earth Online
Wednesday, 30 April 2014 - 17:27

The Met Office/CEH report discusses this; it doesn't say the storms were due to the jet stream and not climate change. It concludes:

"In terms of the storms and floods of winter 2013/2014, it is not possible, yet, to give a definitive answer on whether climate change has been a contributor or not. The climatological context discussed earlier was unusual, with the Atlantic jet stream being more intense and reaching further back into the tropical East Pacific than normal. Those factors in themselves would allow warmer and moister air to enter the storm systems. It is also the case that the sub-tropical Atlantic is now warmer than it was several decades ago and that too would act to enhance the moisture content of the storms."

The scientists here acknowledge we can't say whether climate change caused particular weather events, but we can say it's making certain kinds of weather more likely.

Tom Marshall, Planet Earth Online
Wednesday, 30 April 2014 - 17:32

http://www.dailymail.co.uk/news/article-2560310/No-global-warming-did-NOT-cause-storms-says-one-Met-Offices-senior-experts.html

Tom, I refer you to this link.

Jon Nemo, Tumble, Llanelli
Thursday, 1 May 2014 - 08:38

Jon - I refer you to this link: http://metofficenews.wordpress.com/2014/02/17/met-office-in-the-media-16-february-2014-response-by-professor-mat-collins-and-the-met-office/

Bob, Devon
Wednesday, 7 May 2014 - 13:46

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