Did climate change have an impact on Storm Desmond?

The exceptional rainfall in Cumbria over the past few days saw the fall of numerous records and has led many to ask whether it is linked to climate change. The records are based on digitised data going back to the 19th Century.

A gauge at Honister Pass recorded 341.4mm of rainfall in the 24-hours up to 1800 GMT on 5 December 2015, making for a new UK record for any 24-hour period. This beat the previous record of 316.4mm set in November 2009 at Seathwaite, also in Cumbria. A new 48-hour record (from 0900 to 0900 hrs) was also set, when 405mm was recorded at Thirlmere in Cumbria in just 38 hrs.

The weekend’s record rainfall was associated with a persistent, south-westerly flow bringing a ‘river of moisture’ from as far away as the Caribbean and the Gulf of Mexico. Ocean temperatures in the West Atlantic are currently well above normal and may well have contributed to the very high levels of moisture in the air masses which unleashed rainfall on the Cumbrian fells.

Professor Dame Julia Slingo, Met Office Chief Scientist, says “It’s too early to say definitively whether climate change has made a contribution to the exceptional rainfall. We anticipated a wet, stormy start to winter in our three-month outlooks, associated with the strong El Niño and other factors.

“However, just as with the stormy winter of two years ago, all the evidence from fundamental physics, and our understanding of our weather systems, suggests there may be a link between climate change and record-breaking winter rainfall. Last month, we published a paper showing that for the same weather pattern, an extended period of extreme UK winter rainfall is now seven times more likely than in a world without human emissions of greenhouse gases.”

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28 Responses to Did climate change have an impact on Storm Desmond?

  1. Roger Firman says:

    Hello,

    I wonder if it would be possible to consider different terminology when describing “records”?

    While accepting the figures quoted are new “records”, for those directly affected, these are events one would wish were not “records”.

    Roger Firman.

  2. Ian Kirby says:

    Regarding the record 24 hr rainfall total. Can you clarify this was an official record as I Understand the Met Office official data for rainfall runs from 9am to 9am.
    News reports are claiming a 350+mm, but was this over an arbitrary 24 hours or the 9 till 9 as set by the Met Office or am I wrong?

    • Hello Ian

      Our standard rainfall records are for a ‘rain-day’ which is measureed between 0900GMT and 0900GMT and the 48 hour record based on this time period was broken over the weekend. The 405mm recroded at Thirlmere is a new 48 hour record exceeding 395.6mm at Seathwaite on 18 to 19 November 2009. These records have long datasets extending back to the 19th Century.

      The ‘any 24 hour’ period records have much shorter datasets as they can only be compiled from tipping bucket rain-gauges for which there is much less historical data. The 341.4mm recorded at Honister Pass recorded in the 24-hours to 1800 GMT on 5 December 2015 is a new record, and the 322.6mm was recorded at Thirlmere and also beat the previous record. The previous record for any 24-hour period on record in the UK, was 316.4mm in the 24-hours 0000 – 2359 GMT on 19 November 2009 at Seathwaite.

      Our extremes pages will be updated to reflect the new records soon http://www.metoffice.gov.uk/public/weather/climate-extremes/#?tab=climateExtremes

  3. jbenton2013 says:

    Yet more lies and spin from the Met Office. Last night Slingo was on the national news saying that man made climate change had made the rainfall experienced in Cumbria seven times more likely to happen.

    It’s long past time Slingo should be removed from her post at the Met Office if the organisation is to have any hope of retaining a shred of credibility.

    • Julia was quoting from a recent research paper that showed that under equivalent weather patterns, extreme rainfall over 10 consecutive winter days is now seven times more likely than in a world without human emissions of greenhouse gases. http://www.metoffice.gov.uk/news/release/archive/2015/BAMS-report

      • rysiekski says:

        are these the same models that can’t predict next week? i see i never got an answer to my question why Met uses the cold 30 year average 61-90 nor why 30 years is seen as a climate range? Any climate must be linked to ice age cycles otherwise its just like comparing the temp difference from 8 am to 9 am and say oo its getting warmer then plotting a prediction line then shrieking we all going to fry by midnight. The climate bable only works by you decontextualing from ice age cycles. According to those charts temps can go up 4 c and still be in normal ranges. The medieveal and bronze ages were warmer. Whenever i show people ice age charts they are stunned at the misinformation coming out of people who claim to be doing science and instead giving the jedi mind tricks 30yr average stuck in the 60s.

      • I thought we had answered your question about averaging periods previously.

        The WMO’s recommendations have a role in the use of 1961-1990 climatology but we also use this period because of practical considerations for data processing.

        The 1961-1990 period has traditionally been used and is currently the WMO’s official climate normal period for long-term climate monitoring. Use of this earlier period can be advantageous for development of global climatologies as it can take time for observational records to be become available from remote or less developed regions and be incorporated in global data archives.

        Many national meteorological services now use a 1981-2010 climatology and we do this in relation to UK climatology http://www.metoffice.gov.uk/climate/uk/summaries. This climatology is more representative of recent conditions and so be better suited for putting e.g. forecasts or information on extreme events into current context. The WMO now recommend use of a 1981-2010 climatology for purposes such as these while maintaining a 1961-1990 climatology for monitoring long-term climate variability and change.

        There was a WMO press release on the subject last year: https://www.wmo.int/pages/mediacentre/press_releases/pr_997_en.html

        Helen

      • jbenton2013 says:

        I have only just got round to reading the first couple of chapters of the BAMS report Peter Stott has attached his name to and although it was obvious from skimming the paper quickly that it was statistically inept I had not realised just how bad it was.

        It would take several pages on this blog to outline the ineptitude of the conclusions on the first chapter dealing with wildfires in California but the most obvious problem is analysis only gives consideration to the post 1960 period and no consideration has been given to adjustment for modern forest management practices which increase the risk of wildfires.

        Peter I know things are desperate, but even I’m surprised you have put your name to this.

    • izen says:

      @-“Last night Slingo was on the national news saying that man made climate change had made the rainfall experienced in Cumbria seven times more likely to happen.”

      You clearly disagree with that figure. What multiplier of risk do YOU think climate change has made to these record events?
      Do you have better supporting evidence for your figure than the research Slingo referenced?

      • jbenton2013 says:

        I didn’t have time to read Stott’s whole report in detail but what I did see was enough to confirm that the work done was statistically inept.
        I’ll have time to look at it more closely later.

    • groanranger says:

      Do you actually have a point to make on the science or are you just here to slag people off? If the latter, you should realise that your petty dislikes are of no interest to anyone else reading this blog.

      • rysiekski says:

        anyone who does challenge the science doesn’t get posted. none of mine have that point out the cherry picking of using the 1961-90 averages. unless we get a series of 1960s winters [some say caused by soviet A bomb testing] they co2ers will always be able to say its warmer.

      • It’s not entirely clear but I assume groanranger’s post is directed at Benton not izen.

  4. Stan Dack says:

    There were massive floods in the 1770’s, these took out most of the bridges on the North East rivers, this would be before climate change was ever thought of. We live on a changing planet!

  5. jbenton2013 says:

    So, it hasn’t taken long for the real culprit of much of the flooding in Cumbria to be exposed for all to see, and it’s not as Slingo claimed in numerous media outlets, anthropogenic CO2.

    As with the Somerset flooding the real culprit here is the lack of maintenance of waterways by the Environment Agency. Numerous bridges and gulley’s in Cumbria were apparently either already blocked or were very quickly blocked by trees and large branches causing waterways to burst their banks.

    The situation would have been even worse had it not been for the valiant effort of local farmers and builders with excavators in working through the worst of the conditions to clear some of the blockages at great risk to their own safety. It is to the eternal discredit of the Environment Agency staff that most of them stood by watching, refusing to participate, and even in some cases obstructing the efforts of the local heroes by claiming they were breaching health and safety rules. Some Environment Agency jobs worth’s even attempted to prevent local farmers from shovelling water back into the rivers because there was some sand mixed with the water. It is to the credit of local farmers that they only told the Environment Agency staff to ‘go away and do something useful’, although using much more robust language.

    Local farmers have apparently expressed concern on numerous occasions about the Environment Agency policy of allowing fallen (and in some cases felled) trees to remain on the ground near watercourses on “environmental grounds”. This was an inevitable result of the lunatic policies adopted some years ago by a highly dysfunctional quango which has been infiltrated by the eco-loons. Along with their refusal to dredge waterways it’s clear this was largely a man made disaster, just as was the case in Somerset.

    • izen says:

      So if the Environment Agency had only known that they needed to dredge rivers to cope with an amount and rate of rainfall that significantly exceeded all recorded past floods everything would have been okay?

      Of course they SHOULD have known the floods would be bigger than any past recorded event because climate change has increased the probability of extreme events by 7.

      • jbenton2013 says:

        You’ve clearly swallowed the hype about this being the greatest rainfall. Perhaps you would be better listening to the Cambridge University team who have just last week published a paper showing that last weeks rainfall is far from unique in that area of Cumbria.

        That’s what’s lacking in alarmists, a sense of historical perspective. Most of the rain gauges only have very short datasets, some under 40 years. Honister, which I assume you are relying on for your assertion is one such case, and it’s not even a proper rain gauge conforming to the minimum required standard. But heh, why would that matter to you.
        If you build houses on floodplains then what can you expect, the clue is in the name.

        If you don’t even know why rivers used to be dredged to increase flow then I’m afraid I don’t have the time to educate you.

    • I disagree. The flooding was caused by a record-breaking almost 14 inches of rainfall in 24 hours falling on already saturated ground.

    • groanranger says:

      This is really just recycling of the sort of diversionary rhetoric we have seen before. It wilfully brushes under he carpet the fact that in this case and in Somerset there were record rainfall totals. Whatever issues may or may not have arisen as a result of flood management, its still true there was unprecedented rainfall. The implication, following Mr B’s logic, is that no weather situation, however bad, could ever cause flooding, because according to him floods happen only as a result of incompetence. That is clearly an absurd position: even if we do our best to protect vulnerable areas, there will still be a point when it rains so much that it overwhelms what we are capable of doing. Rather than the deliberate oversimplification presented in the above comment, its pretty clear that there are multiple factors that contribute to the occurrence of flooding, including the defences that have or have not been provided, how the river is managed, and the weather. And the latter is by no means the least important.

      • jbenton2013 says:

        Where did I say no flooding would happen? If you’re going to challenge my comment then do have the courtesy of repeating my words in your comment.

        Or are you only interested in diverting the discussion away from the Environmental Agencies deficiencies.

  6. groanranger says:

    Seems like the wrong question. To me, it should be ‘how much effect did it have?’. Changes in greenhouse gases, and other climate-relevant effects like changes in land use, must have an effect on atmospheric heating, evaporation, run-off etc etc day-in day-out. So it seems trivial to answer ‘yes’ to the question posed above – there must be at least some effect. The interesting thing to know is how much climate change alters how often we get the sort of occurrences we are talking about here. This depends on the size of the climate change effect, compared against how much the climate would vary anyway.

  7. xmetman says:

    I can’t agree with either Dame Julia or the BAMS report which says extreme rainfall events are “seven times” more likely after looking at the daily regional UKP data that you make available.

    Although I didn’t look at 10 day winter events directly, I did look at the frequency of days with 20 mm or more of rain, and although the number has increased in northwest England and north Wales by 28% since 1931, they have fallen by 22% in northern Scotland during the same time. Can the BAMS report explain the reasons for that? Surely all areas should show a similar kind of increase in very wet days?

    https://xmetman.wordpress.com/2015/12/09/seven-times-more-likely/

  8. Another attempt to comment. The Cumbria flooding was caused by record-breaking amounts of rainfall over a 24 hour (and longer) period of time. Enough, eventually, for rivers to overtop the new defences. And rainfall falling onto already saturated ground.

    • jbenton2013 says:

      According to the Cambridge University team there was nothing remarkable about this latest rainfall.

      • Benton: Here is a link to, or reporting on and summarising, the paper you allude to:
        http://www.cam.ac.uk/research/news/unprecedented-storms-and-floods-are-more-common-than-we-think
        Note the somewhat speculative nature of the conclusions (due I imagine to lack of detailed accurate historic rainfall records extending back into past centuries for this and similar wet upland regions). And there is nothing in the article stating that the researchers concluded that the rainfall leading to the flooding in Cumbria was unremarkable. Nothing. Just a suggestion that the intense rainfall of 24 hours and more early this month (ie possibly excluding the wetness of preceding weeks) might not have been unprecedented. From this link they did not convincingly show (with actual statistics) that the rainfall was far from unique, rather they speculated that that might be the case based upon historic records going back several centuries of ‘flood deposits’ (including from times when there would have been less sophisticated flood defences along river valleys presumably). And one researcher is quoted as saying “It is of concern that historical data suggests there is far more capacity in the North Atlantic climate system to produce wetter and more prolonged flood-rich periods than hitherto experienced in the 21st century. Looking forward, an increased likelihood of weather extremes due to climate change means that extending our flood record using geomorphology science must be placed at the centre of flood risk assessment in the UK.” In essence he’s allowing for climate change making extreme rainfall more frequent and suggesting that this factor might make worse a historic flooding risk which he thinks might have been underestimated.
        Incidentally I also briefly commented here:
        https://michaelroberts4004.wordpress.com/2015/12/10/unprecedented-storms-and-floods-are-more-common-than-we-think/#comments

  9. jbenton2013 says:

    Their explanation of their own paper seems pretty clear.

    Dr Tom Spencer from the University of Cambridge said: “In the House of Commons on Monday (December 7), the Environment Secretary called the flooding in north-west England ‘unprecedented’ and ‘consistent with climate change trends’. But is this actually true?

    “Conventional methods of analysing river flow gauge records cannot answer these questions because upland catchments usually have no or very short records of water levels of around 30 or 40 years. In fact, recent careful scientific analysis of palaeoflood deposits (flood deposits dating back hundreds of years) in the UK uplands shows that 21st-century floods are not unprecedented in terms of both their frequency (they were more frequent before 1960) and magnitude (the biggest events occurred during the 17th–19th centuries).”

    Professor Mark Macklin, an expert in river flooding and climate change impacts at Aberystwyth University, said: “UK documentary records and old flood deposits dating back hundreds of years indicate that these floods are not unprecedented, which means we are grossly underestimating flood risk and endangering peoples’ lives.

  10. Like I said I see no statistics there, only unverifiable claims that the recent Cumbria flooding wasn’t unprecedented. And the flooding (caused by record-breaking short-term rainfall onto saturated ground and draining into swollen rivers) was still remarkable even if not unprecedented over the past few centuries as claimed.

  11. simon2037 says:

    Met Office data at http://www.metoffice.gov.uk/climate/uk/summaries/actualmonthly show that the present rainfall is not unprecedented. In the early 20th century it was much the same, despite the militant environmentalists’ claims of global warming. The situation is exacerbated by inadequate dredging, no sensible waterway planning, and government cuts. We taxpayers pay for the result, to punish us until we recant and join the few who espouse global warming as a cult, a religion. No one has ever dared poll all the world’s scientists to ask for an opinion as to whether humans are able to change the climate.

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