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Expert predicts ‘Monsoon Britain’

January 27, 2013

By Paul Homewood

 

Prof Stuart Lane

 

h/t Robuk

 

A study, by Professor Stuart Lane of Durham University back in 2008, appears to have been remarkably percipient. Written just after the extremely wet summer of 2007, the study suggests that, far from summers in the UK becoming drier as most climate models predict, they are likely to become wetter.

Lane makes the following points.

  • The wetter weather in 2007, and which he forecasts will continue to be the pattern, is the result of the movement of the jet stream onto a more southerly track. (This, of course, is exactly what happened in 2012).
  • The period 1960-90 was an unusually dry one, especially compared to the 19th and early 20thC.
  • Three-quarters of our flood records start in the flood-poor period that began in the 1960’s. As a result, the frequency of flooding has been underestimated, leading to building on flood plains, etc.
  • Examining seasonal rainfall data and river flow patterns back to 1753, suggests many other “flood-rich periods” in the past which are comparable to now.
  • We have forgotten “just how normal flooding is in the UK”.
  • Linking heavier rainfall to global warming was wrong.

 

 

News Release

Last summer was the second wettest on record and experts who have studied rainfall and river flow patterns over 250 years say we must prepare for worse to come. Professor Stuart Lane, from Durham University’s new Institute of Hazard and Risk, says that after about 30 to 40 less eventful years, we seem to be entering a ‘flood-rich’ period. More flooding is likely over a number of decades.

Prof. Lane, who publishes his research in the current edition of the academic journal Geography, set out to examine the wet summer of 2007 in the light of climate change. His work shows that some of the links made between the summer 2007 floods and climate change were wrong. Our current predictions of climate change for summer should result in weather patterns that were the exact opposite of what actually happened in 2007. The British summer is a product of the UK’s weather conveyor belt and the progress of the Circumpolar Vortex or ‘jet stream’. This determines whether we have high or low pressure systems over the UK. Usually the jet stream weakens and moves northwards during spring and into summer. This move signals the change from our winter-spring cyclonic weather to more stable weather during the summer. High pressure systems extend from the south allowing warm air to give us our British summer.

In 2007, the jet stream stayed well south of its normal position for June and July, causing low pressure systems to track over the UK, becoming slow moving as they did so. This has happened in summer before, but not to the same degree. Prof. Lane shows that the British summer can often be very wet – about ten per cent of summers are wetter than a normal winter. What we don’t know is whether climate change will make this happen more in the future.

 However, in looking at longer rainfall and river flow records, Prof. Lane shows that we have forgotten just how normal flooding in the UK is. He looked at seasonal rainfall and river flow patterns dating back to 1753 which suggest fluctuations between very wet and very dry periods, each lasting for a few years at a time, but also very long periods of a few decades that can be particularly wet or particularly dry. In terms of river flooding, the period since the early 1960s and until the late 1990s appears to be relatively flood free, especially when compared with some periods in the late 19th century and early 20th Century.

As a result of analysing rainfall and river flow patterns, Prof. Lane believes that the UK is entering a flood rich period that we haven’t seen for a number of decades. He said: “We entered a generally flood-poor period in the 1960s, earlier in some parts of the country, later in others. This does not mean there was no flooding, just that there was much less than before the 1960s and what we are seeing now. This has lowered our own awareness of flood risk in the UK. This has made it easier to go on building on floodplains. It has also helped us to believe that we can manage flooding without too much cost, simply because there was not that much flooding to manage.” He added: “We have also not been good at recognising just how flood-prone we can be. More than three-quarters of our flood records start in the flood-poor period that begins in the 1960s. This matters because we set our flood protection in terms of return periods – the average number of years between floods of a given size. We have probably under-estimated the frequency of flooding, which is now happening, as it did before the 1960s, much more often that we are used to. “The problem is that many of our decisions over what development to allow and what defences to build rely upon a good estimate of these return periods.

The government estimates that 2.1 million properties and 5 million people are at risk of flooding. In his review of the summer floods Sir Michael Pitt was wise to say that flooding should be given the same priority as terrorism.” Professor Lane concluded: “We are now having to learn to live with levels of flooding that are beyond most people’s living memory, something that most of us have forgotten how to do.”

Flooding is one of the issues covered by the Institute of Hazard and Risk Research at Durham University where Prof. Lane is a resident expert. The IHRR, which launches this week, is a new and unique interdisciplinary research institute committed to delivering fundamental research on hazards and risks and to harness this knowledge to inform global policy. It aims to improve human responses to both age-old hazards such as volcanoes, earthquakes, landslides and floods as well as the new and uncertain risks of climate change, surveillance, terror and emerging technologies. Prof. Lane’s research is funded by the Willis Research Network, an innovative collaboration between universities worldwide and the insurance industry, and The UK Research Councils’ Rural Economy and Land Use Programme.

 

 

http://www.dur.ac.uk/news/newsitem/?itemno=6468

 

 

Perhaps Julia Slingo should read this paper.

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7 Comments leave one →
  1. John F. Hultquist permalink
    January 27, 2013 5:33 pm

    Americans and Brits seem much more interested in documenting the titillating goings on of Hollywood (U.S.) and Peerage (Br.) members than they do in keeping track of the natural world. One might think (and apparently wrongly so) that an orderly society such as the UK would have well documented records of storms, floods, dry periods, and so on. But the report says “Three-quarters of our flood records start in the flood-poor period that began in the 1960’s.” That’s hard to believe.
    Note the source of funds for this IHRR includes “the insurance industry” that very much needs to figure out actuary assessments for these events. I guess they must think higher rates can be charged insuring against damages from global warming events rather than those from natural variation.

    Prof. Lane’s study seems a useful addition. Of interest is this statement:
    “. . . we set our flood protection in terms of return periods – the average number of years between floods . . .”
    When Sydney, AU was flooding a year or two ago there was a report or statement from a civil engineer professor from a technical institution about this. His claim was that this “return periods” approach was seriously flawed and needed major changes. I suspect I picked this up on the Jonova site and will search (later) for it.

  2. Robuk permalink
    January 27, 2013 5:37 pm

    Hi,

    I posted this study as I felt it undermined the climate disruption term being used at present.

    Decades of predominantly wet or dry.

  3. Robuk permalink
    January 27, 2013 6:29 pm

    Will the BBC be reporting flooding as an extreme event.

    The pattern of changes in extremes uncovered by the research matches the predictions made in a number of climate models. Dr Fowler, author of the study at Newcastle University, claims ‘the changes in the 40 year period are consistent with the trend we would expect from global warming’.

    But Philip Eden, one of the country’s leading and most respected climatologists, argues that the claims could be misleading. The problem, he says, is down to the short period of rainfall statistics analysed.

    He claims that by taking a much longer time period, for example the whole of the 20th century, the frequency of high intensity rainfall events that we have witnessed in the past 30 years is not unusual.

    The eras of heaviest summer downpours have actually coincided with cooler summers, not warmer summers, in particular 1912-1931, and again from 1948-1969.

    http://www.bbc.co.uk/blogs/paulhudson/2010/11/is-the-perceived-rise-in-flood.shtml

  4. Mick J permalink
    January 28, 2013 1:50 pm

    This may interest:

    “Scientists blame warmer Atlantic for wet summers
    David Shukman By David Shukman Science editor, BBC News
    A man holding an umbrella Britain experienced one of its rainiest summers in a century
    Continue reading the main story
    Related Stories

    Summer is ‘wettest in 100 years’
    Why, oh why, does it keep raining?

    Recent warming in the Atlantic Ocean is the main cause of wet summers in northern Europe, according to a new study.

    A cyclical pattern of rising and falling ocean temperatures is seen as a major influence on our weather.

    Scientists say the current pattern will last as long as the Atlantic warming persists.

    The research was carried out at the University of Reading and is published in the journal Nature Geoscience.

    The study investigated a phenomenon known as the Atlantic Multidecadal Oscillation – a cycle of change in which the waters either warm or cool over a period of several decades.

    The researchers compared three periods in this cycle: a warm state from 1931-60, a cool period from 1961-90 and the most recent warm period starting in 1990 and continuing now.

    The paper notes that conditions in the last warm period in the Atlantic are broadly similar to those observed now.

    So the study compared weather conditions in Europe during the two warm Atlantic phases with those experienced in the cool phase.

    One conclusion is that a warmer-than-usual Atlantic “favours a mild spring (especially April), summer and autumn, in England and across Europe.”

    Another finding – of greatest relevance to the search for a cause of rainy summers – is that the warmth of the ocean also tends to make northern and central Europe wetter than usual. By contrast southern Europe, from Portugal to Turkey, gets far less rain than normal.

    That was the pattern observed last summer.
    Jet stream

    The precise mechanism by which the temperature of the surface of the ocean drives weather systems is not well understood.

    But it is thought the changes in pressure influence the path of the jet stream, and how much it “meanders”. Regions to the north of the stream, as Britain was for much of the summer, tend to be on the receiving end of a succession of rain storms.”

    More at http://www.bbc.co.uk/news/science-environment-19848112

  5. Bobby@aol.com permalink
    June 27, 2013 11:21 pm

    It’s rather silly trying to tie individual events such as a singles season of increased rainfall to the overall warming of the earth.

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