2015 Was Not Unusually Wet

By Paul Homewood 

 

http://www.metoffice.gov.uk/hadobs/hadukp/data/monthly/HadEWP_monthly_qc.txt

 

Contrary to various misleading claims, last year was not “one of the wettest” on record. In fact it only ranked 84th wettest since 1766, according to the England & Wales Precipitation Series, with 969mm, only marginally above the average of 918mm.

As the 10-Year average shows, there have been wetter periods than the last 10 years in the past. The wettest such period was 1874-83. The 1770’s and 1920’s were also exceptionally wet.

 

The Met Office often likes to claim that most of the wettest years have occurred in the last decade or two, but again the facts show this not to be true:

 

 

 

 

Although four years since 2000 appear in the Top 20, such clustering is not unusual. What is notable though is the complete absence of the wettest years between 1960 and 2000.

It is understandable, therefore, why the public find current weather “exceptional”. However, it is inexcusable for the Met Office not to provide the longer term perspective, which would show otherwise.

This pattern of rainfall is, in any event, well known. It was the Durham University flood expert, Professor Stuart Lane, who looked at seasonal rainfall and river flow patterns dating back to 1753 and found 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.

 

It is important to note that the England & Wales Precipitation Series has been carefully put together since its inception in 1931. In particular, great care has been taken to ensure that historical comparisons are meaningful. When one station drops out, the homogeneity of the series is preserved by normalising stations’ precipitation relative to the correct long-term local averages and by ensuring that the variance of the series has no artificial fluctuations.

The series is currently based on about 100 stations. Some of the early data was more patchy, up to around 1800, but the mid 19thC  ample data is available. (According to Wikipedia, some of the earlier rainfall data may have been underestimated, due to little recording of upland sites).

Put simply, there is absolutely no reason at all for the Met Office not to be using the series in their public pronouncements. Indeed, one of the concerns with their 1910 digital series is that it has increasingly factored in new automated MMS systems, situated in wet, mountainous and upland areas, thus adding a wet bias.

According to one commenter, their reluctance to use the 1766 series is that it has too few regional records. But even this is not true, as the EWP has regional data starting in 1873. There is also the excellent Symon’s British Rainfall publications, which began in 1860 and contain a wealth of rainfall statistics.

 

It is hard to avoid the conclusion that their reluctance to report the EWP data is that it would utterly discredit their regular attempts to persuade us that our climate is getting wetter and floods worse.