Lord Deben, Chairman of the UK Committee on Climate Change has spoken out following severe flooding which has occurred across Scotland and parts of Northern England. One of the worst affected areas of Cumbria has experienced a series of severe floods over the last decade in 2005 and again in 2009.

"This devastating flooding is a timely reminder that climate change is expected to increase the frequency and magnitude of severe flooding across the UK," he said.

Despite significant investment taking place in recent years – £38M was spent improving flood defences in Carlisle after the 2005 floods; £4.4M in Cockermouth and £6M in Keswick after 2009 – Deben warned that severe flooding can still be expected and that current rainfall totals had exceeded the higher defence levels which have been put in place. Defences that might historically have provided protection against a 1 in 100 year flood will, he says, provide a much lower level of protection and be overtopped more frequently with climate change. The latest projections suggest periods of intense rainfall could increase in frequency by a factor of five this century as global temperatures rise.

"If the Paris climate change talks make good progress, and warming is limited to no more than 2°C, then with additional flood risk management effort the UK should be able to avoid increasing flood risks and impacts," Deben commented. "However, if global greenhouse gas emissions do not peak soon and start to fall, four or more degrees of warming could take place this century. This would lead to severe and unavoidable increases in UK flood risk."

Indeed experts believe if average global temperatures rise by 4°C, expected UK flood damage would double, even assuming government investment continues in flood defences. An extra one million UK homes would be exposed to a high risk of flood damage, with a 1-in-75 or greater chance of flooding in any given year. Deben added that, with this in mind, the importance of securing a strong and binding deal in Paris at COP21 cannot be over emphasised.

"Events like this serve as a harsh reminder of the finite capacity of our flood defences, and the destructive impact extreme flooding has on our communities," says Professor David Balmforth, Flood Expert and Past President of the Institution of Civil Engineers. He went on to add that government commitment to invest £2.3B in flood risk management over the next six years "was welcome" but warned as extreme weather events become more frequent and unpredictable, "we will need a more holistic approach to flood resilience".

Darrell Matthews, Regional Director of the North West region of the Institution of Civil Engineers, commented that even flood defences expertly designed to last a century can be overwhelmed by the kind of weather the UK has just experienced.

"We are looking at situations where flood defences have done what they were designed to do, and have held back the floods for as long as possible," he said. "This has bought time for emergency measures to be taken to keep people safe. The expertise of the engineers involved in designing and building the defences will also be key in future plans to ensure that Cumbria has a level of defence that protects its people, and their property."

According to the UK Met Office the rainfall experienced in Cumbria this week was "exceptional". Professor Dame Julia Slingo, Met Office Chief Scientist, said: "It’s too early to say definitively whether climate change has made a contribution to the exceptional rainfall. However, just as with the stormy winter of two years ago, all the evidence from fundamental physics, and our understanding of our weather systems, suggests there may be a link between climate change and record-breaking winter rainfall. Only last month, we published a paper showing that for the same weather pattern, an extended period of extreme UK winter rainfall is now seven times more likely than in a world without human emissions of greenhouse gases."