A handle on the weather

Handle on the weather

A Record Number of Records? For the record . . .

There has been a lot of talk about record breaking weather in the last few weeks. You can find plenty of comment around the web on the amount of rain, on the reasons for the rain, the causes of the flooding, the failings of the government and the camaraderie and stoicism of British people in the face of adversity.

Throughout all of this, the fact remains that the media loves a record breaker. To claim something is the “fastest ever”, the “longest ever”, the “oldest ever” or the what-ever, makes for great headlines. As a result we are continually bombarded with stories of extremes and expected to draw the conclusion that strange things are happening, but I wanted to make one simple mathematical observation.

In the course of any given year we will hear weather commentators observing different phenomenon in our daily lives; wettest, driest, hottest, coldest, sunniest, least sunny, windiest, snowiest (I’m sure there are more) – that makes 8 types of weather at least.

Then we are told that new levels have been reached over a particular period; a month, 2 months, 3 months, 4 months, a year. There are 12x 1-month periods, 12x 2-month (consecutive) periods, 12x 3-month periods etc. – that adds up to 49 time periods.

The next qualifier is the area covered by such a statement; the whole country, a county, an area (whatever that is) – we have 98 counties in the UK, allowing for 200 undefined ‘areas’ or ‘parts’ (as in “Parts of the country have seen the heaviest rain since…”) presuming them to be smaller than counties, that makes 300 geographical zones in the country. I think this is a pretty low estimate, people often talk in terms of areas as small as a town and clearly we have thousands of these but I’ll stick with 300 for now.

Finally commentators pick the period over which they make comparison. This is a favourite way of manipulating the dramatic effect. We might hear that we have had the “coldest winter in 50 years”, why 50 years? Because there were colder periods earlier, and saying the “4th coldest in the last 75 years” or the “7th coldest in the last hundred” isn’t nearly so dramatic.

So how many time periods are we talking about? 25yrs, 50yrs, 100yrs, start of the 20th Century, 150yr, 200yr, since records began, that makes 7, although I recognise that not all parameters have been measured for that long. Let’s say 5.

So that means we effectively have
8 x 49 x 300 x 5 = 588,000 different records.

That’s over half a million UK weather “records”. I would therefore contend that it is not in the least bit surprising that we have recently seen a number of rain records broken – there are over 70,000 of them.

To give you an example of this over-dramatisation of weather events, I saw a report that in 2012 the arctic ice was at its ninth lowest level since satellite records began. Shocking, frightening, a clear indicator of global warming? Until you realise that records only began in 1979, that’s 33 years. If the ice were at its average it would be the 16th lowest. The ninth lowest isn’t even in the bottom 25% of values.

So that’s the end of the longest ever blog post . . . about the weather . . . in the history . . . of this blog.

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