So what about 1929, Julia?

By Paul Homewood

 

http://www.bbc.co.uk/news/uk-politics-26084625

 

“All the evidence suggests there is a link to climate change”, says Julia Slingo.

There is a slight problem though – the Met Office report she quotes , “The Recent Storms and Floods in the UK”, says no such thing at all. What it does say is that recent weather events are linked to “major perturbations to the Pacific and North Atlantic jet streams driven, in part, by persistent rainfall over Indonesia and the tropical West Pacific.”

The report speculates that this may all be connected to warmer waters in the Tropical West Pacific, without explaining what has, in turn, caused this.

I will leave this matter in the capable hands others, but the report itself concludes “In terms of the storms and floods of winter 2013/2014, it is not possible, yet, to give a definitive answer on whether climate change has been a contributor or not”

I would, though, leave the question – as these waters have been warmer for the last decade, a fact the report acknowledges, why have we not seen this particular jet stream phenomenon before?

(In passing, it is worth noting that there is no attempt to blame “melting Arctic ice”. Does this mean that theory is now in the garbage can?)

 

But what I am more interested in, as far as this post is concerned, is the question of how unusual this winter’s weather has been. The report points to how wet it has been in the last two months, but as even Slingo herself admits, it has not been unprecedented.

 

 

According to Met Office data, there have been eight other 2-month periods in England, which have been wetter since 1910, than the last two months total of 274mm. (The different England & Wales dataset, which dates to 1766, also shows that there were five years, prior to 1910, that also had higher 2-month totals : 1771, 1811, 1822, 1852 and 1877).

 

	Precipitation mm
Oct – Nov
1929	286
1960	294
2000	322
Nov – Dec
1914	281
1929	340
2000	277
Dec – Jan
1914/15	276
1929/30	280

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Rainfall/date/England.txt

 

Note also that in 1914/15, 1929/30 and 2000/01, the high levels of rainfall extended over three months, not just two.

 

We sometimes get hung up about measuring rainfall in “seasonal blocks”, such as December to February. The reality, in the UK at least, is that the wettest months of the year are October through January. It seems logical, therefore, to use these four months when looking at trends, etc.

 

http://www.metoffice.gov.uk/public/weather/climate/yeovilton-somerset#?tab=climateGraphs

 

Over this full four month period, by far the wettest year was 1929/30. This latest period ranks only fourth, certainly exceptionally wet, but hardly “biblical”, as David Cameron has described it.

 

Equally relevant is the fact that the 10-year trend is, if anything, lower than much of the first half of the 20thC, and shows no sign of increasing. (Although, it is higher than the relatively dry interlude of the 1960’s and 70’s). If global warming really was leading to wetter winters, why have we not seen any sign of this yet?

 

Figure 1

http://www.metoffice.gov.uk/pub/data/weather/uk/climate/datasets/Rainfall/date/England.txt

 

Figure 2

 

Storminess

The report also addresses the issue of storms, but accepts that this winter has been no stormier than 1993. (It certainly would not compare, either, with 1991, the year of the Burns Day Storm, the first of 12 severe gales to hit the country in the space of 6 weeks).

It is also worth noting that the UK Climate Projections Report , issued in 2012, finds that:

Severe windstorms around the UK have become more frequent in the past few decades, although not above that seen in the 1920s.

Whereas it is not our purpose here to discuss detailed links between the NAO and storminess, it will be immediately apparent that the two stormiest periods in Figure 1.14, in the 1920s and 1990s, coincide with decades of sustained positive NAO index, whereas the least stormy decade, the 1960s, is a time when the smoothed NAO index was most negative.

There continues to be little evidence that the recent increase in storminess over the UK is related to man-made climate change.

 

3-Month Outlook

http://www.metoffice.gov.uk/media/pdf/m/8/A3_plots-precip-DJF-2.pdf

 

It is all very well for the Met Office to claim that they know the reason for the recent wet and stormy weather, but it is clear they knew no such thing last November, when they forecast the likely probability of a dry winter. Certainly, the factors in the Pacific, that they now blame, were in play at the time. (If they were not, then they are just “weather”, and cannot be claimed to be linked to “climate change”).

None of this gives us much confidence in the Met Office’s ability to forecast more than a few days out. But it must surely also cast doubt on the worth of the latest report, which seems to be a rushed attempt to explain recent bad weather.

 

 

 

Conclusion

It is somewhat encouraging that Slingo and her colleagues at the Met Office are starting to realise that weather patterns are far too complex to simplistically attribute to “melting Arctic ice”, or “global warming”.

A better understanding of what drives changes in the jet stream, the QBO, and a host of other factors, can only help us in anticipating future weather patterns. To do this, though, needs an acceptance that similar events have happened in the past, and that such events may give us a clue as to what is happening now, and will inevitably happen again in the future.

Where, for instance, is the recognition that 1929/30 had a much longer and wetter spell? And where is the analysis of of what drove the weather then? What, if any, are the similarities between the two years?

It is disappointing then to read the Met Office press release saying:

More research is urgently needed to deliver robust detection of changes in storminess and daily/hourly rain rates and this is an area of active research in the Met Office. The attribution of these changes to anthropogenic global warming requires climate models of sufficient resolution to capture storms and their associated rainfall.

Surely to do science properly, they should be looking to understand what drives weather patterns, regardless of the causes. To start out by attempting to “attribute changes to AGW” is likely to skew results towards their preconceptions, and will undoubtedly lead to a poorer understanding of the Earth’s climate as so many other natural mechanisms will be ignored.

Meanwhile, Julia Slingo goes for the cheap headline.

 

 

Afterthought

It is clear that this report has been an extremely rushed affair. Certainly, even at the end of December, there was no indication of anything unusual at all with rainfall totals. This would imply that the report was probably not started until two or three weeks ago.

If they had wanted to do a full, proper study, it should, of course, have taken months to get all the data in, and analyse it effectively. So, why was it rushed out so quickly?

Was it commissioned for political reasons, and if so by whom, the Government or the Met Office?

And what agenda lay behind it? Was it merely another attempt by Slingo and co to blame it all on global warming? Or did the Government want to cover its back, over its failure to deal effectively with the floods?

I would also question just when it was decided to link everything back to the warm pool in the Western Pacific. I have good reason to ask this question, because, on 7th Jan, the Met Office issued a press release about the polar vortex over America. This made absolutely no mention at all of any link to the Western Pacific. It all rather gives the impression of being made up on the spur of the moment.

 

 

N.B. Why is there no mention at all of the sun?