There is nothing in the data to provide the slightest bit of evidence that the floods have been the result of, or aggravated by climate change. Nor is there any indication that such events are becoming more common, or more extreme.
The December floods in England have been a big story recently, and, of course, still remain a problem. The term “extreme weather” has been bandied about, along with the inevitable connotation of “climate change”. ( I may be wrong, but years ago we rarely seemed to hear this term – it was usually just called “bad weather”, or simply referred to as “wet”, “stormy”, “cold” etc).
Nobody, of course, actually quantifies any of this, but the inference is made nevertheless. A good example came in the Telegraph, in an otherwise sensible article by William Langley:
Earlier this year, the Government agreed a deal with insurers that would nominally protect 500,000 households in areas deemed to be at such high risk their owners are unable to get cover. The £180 million raised each year — which would be managed by a not-for-profit fund known as Flood Re — ensures properties remain insurable through a £10.50-a-year levy on all residential premiums due to be introduced in 2015.
But critics say the scheme allows for no increase in the likely numbers of flood victims as weather patterns become increasingly severe and new homes are built in areas previously considered off limits because of flood risk.
So what exactly are the facts? How unusual has the recent rainfall been, and is there a trend to heavier rainfall?
Scotland has certainly been very wet in December, but I want to concentrate on England, as this is where most of the media attention, and, it seems, damage has been.
First we’ll look at England as a whole, then concentrate on the South East, where the real problems have been.
Figure 1 shows December precipitation, using the Met Office data. For the country as a whole, last month was only the 20th wettest since 1910, certainly nothing out of the ordinary. The wettest month was in 1914, when 179mm fell, compared with 116mm this time. Bear in mind as well, that this is just one month of the year – there will be plenty of Januaries, Februaries and so on that were wetter.
Neither does there appear to be any evidence of wetter months becoming more common.
The flooding problems have been very much the result of a build up of water, rather than flash floods, with saturated ground and full rivers. So was December the culmination of months of wet weather. We can check this by going back to October. (November and September were both dry months, so we are taking the worst case scenario here).
For the three months as a whole, 2013 ranks as still only 14th wettest, again nothing remarkable, and 29% lower than the record total set in 1929. […]
Winter Precipitation Trends
Is there any trend towards higher winter rainfall in England. To check this we have the benefit of the long term England & Wales Precipitation Series, held by the Met Office, which dates back to 1766.
There is clear evidence that winter precipitation was consistently lower in the first part of the record, up to about 1860. But since then, and certainly over the last century, the long term trend is pretty flat, with, if anything, a trend to less rain over the last decade or so.
The wet weather has continued into January so far, and hopefully will abate soon. We will get a better picture when we can look at the full winter period.
Nevertheless, there is nothing in the data to provide the slightest bit of evidence that the floods have been the result of, or aggravated by, “climate change”. Nor is there any indication that such events are becoming more common, or more extreme.
Only today, Bishop Hill refers to two separate comments by Sirs John Beddington and David King, respectively current and former UK Govt Chief Scientists, both of which imply that recent events are examples of extreme weather, which is increasing because of “climate change”. Naturally, they offer not the slightest bit of evidence. This did not prevent the BBC and Guardian respectively from falling for it hook, line and sinker.