Probabilities

Along with the terrible news coming from Japan and New Zealand over the last few days and weeks, there has been a lot of talk in the media about the earthquakes and tsunamis being "1 in so many year" events.

These comparisons of probability are useful - they give an idea of magnitude.  But they can also make us complacent - the temptation now is to think we won't get any more events like that for a long time; "we have had the 1 in 100 year" event.

But that's not how the maths works.  If you have a dice - where 1 is a small event and 6 is a big event - you throw it and get a six; we all know that it doesn't mean you won't get a 6 in the next few throws.  You may, indeed, get one on the very next throw of the dice (and the next).  All measurements of probability are entirely the same.  Each time you throw the dice the probability of throwing another 6 remains the same - 1 in 6.

In recent years we have had flood damage in many parts of our diocese.  Not least in Hull during 2007.  Of course part of the flooding was caused by the "1 in 150 year magnitude" rainfall.  But much of the damage was exacerbated by poorly maintained drainage and water course systems.  The "1 in 150 year" event (which the Hull rainfall was described as) could happen again tomorrow - but are we any more prepared for it?

As we think about our environment are we still keeping our eyes on the ball and continuing to invest - as individuals and local authorities - in maintaining the many systems that can alleviate the effects of natural disaster?

Graham Andrews