“Climate change and the UK floods”

http://www.theccc.org.uk/ccc-blog/

There is no shortage of debate over whether the recent storms and floods can be blamed on climate change. In reality any answer will involve probabilities rather than a simple ‘yes’ or ‘no’. So what do we know, what are the uncertainties, and can we say whether or not there is a clear link?

Despite the current lack of a precise answer, the recent heavy rainfall and coastal inundation is consistent with some basic physics of a warming world:

• Firstly, sea levels are rising. During the last century the sea level in the English Channel has risen by around 12 cm and is continuing to rise at a rate of 1.3cm per decade. This is because land-based snow and ice is melting into the sea and because seawater expands as it warms. Higher seas mean a greater chance of storm surges breaching coastal defences.

• Secondly, warmer air can hold more moisture. So, in a warmer world, a given storm has the capacity to drop more rain. While rainfall in the UK varies a lot from year to year there is some evidence to suggest that extreme rainfall is becoming more common – what was a 1-in-125 day event seems to be occurring on average every 85 days now.

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