Wednesday, 30 December 2015

More on the 'Unprecedented' Rainfall Causing UK Floooding

In response to me linking to my latest blog post on Twitter, BBC weatherman and meteorologist Simon King pointed me to this graph of UK annual rainfall  since 1910 which shows a significant increase in trend since 1980 - a point which he made when being interviewed on BBC FiveLive apparently.
uk
Aside from the fact that the UK series is very much shorter than the EWP which goes back to 1766, there is indeed a marked positive trend in UK annual rainfall, starting around 1973, and exceeding that of 1910. Here is the corresponding graph for England:
england
And for Wales:
wales
Though the same trend exists, it is not very pronounced. It is more pronounced for Northern Ireland:
northern_ireland
It is a lot more pronounced for Scotland:
scotland
Thus, it would appear that the overall increase in annual UK precipitation from 1973 is due in large measure to an increase in rainfall in Scotland, with a lesser contribution from Northern Ireland and only very minor contributions from England and Wales.
Cumbria, Lancashire and Yorkshire are of course in England and the Environment Agency is of course responsible only for flood defences in England. So pointing out that rainfall in the UK has increased significantly, when much of that increase has been in Scotland and Northern Ireland, is not that relevant, particularly when the flooding in England has provoked sharp criticism of England's freshwater flood preparedness measures as managed (badly, it seems) by the Environment Agency. It is even more irrelevant in that even the UK annual rainfall data shows there has been no really significant increase in Winter precipitation since 1910, the issue at present being winter rainfall causing flooding.
uk1
2014 again stands out but there is very little overall increase in trend since 1910. Given the fact that winter 2015/16 still has 2 more months to go, it may or may not turn out out to be a particularly wet winter overall.
The lesson here (if there is one) is, don't listen to BBC Radio FiveLive if you want all the facts about current severe flooding and what may be contributing to it.