Provisional statistics from the Met Office show 2012 was the second wettest year in the UK national record dating back to 1910, and just a few millimetres short of the record set in 2000. The exceptionally wet year was characterised by a dry start which quickly gave way to very wet weather, with April and June both being the wettest on record.
Unsettled weather continued through to the end of the year, with December being the 8th wettest on record for the UK. The persistent wet weather resulted in total 2012 rainfall for the UK of 1330.7 mm, which is just 6.6 mm short of the record set in 2000.
Looking at individual countries, 2012 was the wettest year on record for England, third wettest for Wales, 17th wettest for Scotlandand 40th wettest for Northern Ireland. This adds to a high frequency of wet years since 2000 in the UK – with four of the top five wettest years occurring since then.
Looking at annual rainfall for the UK, it is clear that the country as a whole getting wetter in recent decades.
Preliminary research from the Met Office also suggests a change in the nature of the rain falling in the UK, with ‘extreme’ daily rainfall becoming more frequent. An analysis of 1 in 100 day rainfall events since 1960 indicates these ‘extreme’ days of rainfall may have become more frequent over time.
Professor Julia Slingo, Chief Scientist at the Met Office, comments: “The trend towards more extreme rainfall events is one we are seeing around the world, in countries such as India and China, and now potentially here in the UK. Much more research is needed to understand more about the causes and potential implications.
“It’s essential we look at how this may impact our rainfall patterns going forward over the next decade and beyond, so we can advise on the frequency of extreme weather in the future and the potential for more surface and river flooding. This will help inform decision-making about the need for future resilience both here in the UK and globally.”
Changes in sea surface temperatures due to natural cycles and reducing amounts of Arctic sea-ice could be influencing the increase in rainfall, but more research needs to be done before anyone can establish how big a role they play.
Increasing global temperatures may be another factor. A warmer atmosphere can hold more moisture and there has been an increase of about 0.7 °C in global temperatures since pre-industrial times.
From basic physics, this would equate to about a 4% increase in moisture in the atmosphere which means there is a greater potential for heavy rain.