This is what global warming looks like: the new age of flooding

The "one-off" floods of July 2007 have inaugurated a new era of extreme weather events - and they're only going to get more frequent.

By Edward Platt

So this is what global warming looks like. In December, 196 nations met in Paris to agree a plan that would limit global temperature rises to 2° Celsius and to “pursue efforts” to limit the increase to 1.5°C; and the mild, wet weather that followed in the UK was a reminder of the need to make good on the commitment. December’s average temperature was 8°C, no less than 4.1°C higher than the average. As a warming climate holds more water, rain inevitably followed.

The floods of July 2007, which caused £3bn worth of damage, were meant to be a one-off event. Instead, they appear to have inaugurated a new era of extreme weather. The list of places overwhelmed by supposedly freak conditions is growing all the time. To Tewkesbury, Hull and the many other places in the north and Midlands that were flooded in 2007, we can now add Morpeth in 2008, Keswick and Cockermouth in 2009, the Welsh town of St Asaph in 2012 and the Somerset Levels during the winter of 2013-14.

Cumbria was the first place affected this year, as a record 340 millimetres of rain fell in 24 hours in early December. The village of Glenridding flooded three times in succession, while Keswick flooded for the third time in ten years. Cockermouth, which spent £4.4m on defences after the floods of 2009 left its Georgian shops and houses under eight feet of water, flooded again. Every river in Lancashire reached its highest recorded level on Boxing Day, and there was flooding in big cities such as York and Leeds. Storm Frank, the sixth storm of the season to merit a name, caused widespread flooding in Scotland. And photographs of a 16th-century castle poised on the edge of the swollen River Dee near the Balmoral estate demonstrate that the threat remains.

Such events are going to become more frequent. One recent study found that global warming made flooding 40 per cent more likely; another predicted that the frequency of severe flooding across Europe will double by 2050, bringing almost a fivefold increase in annual economic losses. Yet government spending on flood defences has not kept pace with the risk. After the floods in 2007, the government said that increases in spending of £30m each year would be needed to contend with the effects of climate change, yet spending was cut at the start of the last parliament from £360m in 2010-11 to less than £270m in 2012-13. Discounting the exceptional sum of £270m spent after the flooding on the Somerset Levels in 2013-14, spending fell by 10 per cent in real terms over the course of the parliament.

David Cameron has promised £40m to fix flood defences in Yorkshire and another £50m elsewhere, but increased spending on defences will only be part of the answer, as the Environment Agency’s deputy chief executive acknowledged: the transition from “known extremes to unknown extremes”, David Rooke said, requires a “complete rethink”.

Some measures will not be popular. When the flooding on the Somerset Levels was at its worst, the government gave in to local demands to dredge the rivers despite evidence that turning them into drains may increase the risk of flooding. As environmentalists such as George Monbiot have convincingly argued, allowing rivers to braid and meander, creating bogs and marshes that hold water in periods of heavy rainfall, may be the best way to reduce the likelihood of both drought and flooding.

The experience of Pickering in Yorkshire, which flooded in 1999 and 2007, illustrates the potential of such schemes: it could not get the funding for a concrete embankment to enclose Pickering Beck, so it resorted to a cheaper attempt to “Slow the Flow” of water by planting woodland and creating dams from logs and branches. So far, Pickering hasn’t flooded.

In the longer term, we will need even bolder changes to the built environment and our attitude towards it. I have met people in places that have always been prone to flooding, such as Hull and Tewkesbury, who said they used to cope with it better because they expected it and lived accordingly. Instead of stripping out the interiors of their homes, as those fortunate enough to get insurance are now required to do, they picked up rugs and furniture and moved upstairs until the water had flowed through.

Resilience is the new watchword: towns and cities must create ponds, soakaways and other channels for excess water. Individual houses must be changed to allow for speedier recovery, with stone floors replacing wood or carpet and electrics lifted above the water’s reach. The process of adapting to our new flood-prone age is just beginning.