The detailed projections are able to show flooding risks in specific areas, and allow scientists to see how coasts, cities and mountains can affect floods. They were also able to calculate hourly rainfall rather than daily using the fine detail enabled by the supercomputer.
Dr Lizzie Kendon, a climate scientist at the Met Office specialising in extreme rainfall explained: “The level of spatial detail we are working with is 10 times finer than the resolution of previous model projections. This is like looking at a digital picture of a person’s face in much greater detail.
"At a lower-resolution you might be able to recognise the person, but at the higher resolution you will see much more detail, including tiny blemishes on the skin. What we’ve been able to do with the UK’s future climate is to model the impacts of extremely localised events, like the one in Boscastle in August 2004, which saw one month’s rainfall fall in just two hours on the Cornish coastal village: you just can’t capture these in coarser projections.”
The projections are based on a scenario in which we have not drastically reduced our carbon emissions.
Flash floods are likely to double under these conditions from a UK-average of once every ten years in the present-day to almost once every five years by the 2070s.
This year has already seen the UK’s highest recorded daily maximum temperature of 38.7 °C in Cambridge on 25 July. In 50 years, this will not be unusual. At the moment, heatwaves above 30 degrees celsius lasting more than two days occur about once every four years. By 2070, under a high emissions scenario, this will increase to four times a year - a 16-fold increase.
Professor Jason Lowe, head of climate science at the Met Office, said: "Whilst the trend is towards warmer and wetter winters, and hotter and drier summers, we will still get some cold years."
Scientists at the Met Office hope they will be able to harness the power of ever more efficient supercomputers in future to make more detailed predictions and help businesses and the government prepare for climate change.
Britain will see four heatwaves a year and twice as many flash floods in 50 years, according to the most detailed long-term projections ever conducted by the Met Office.
The weather forecasters used their powerful supercomputer to make hyper-local predictions, enlisting top climate scientists to analyse the data. The projection took a year of computer time because there were so many calculations to make.
These local (2.2km) climate projections have allowed the Met Office and Defra to see the challenges posed by climate change in "unprecedented detail", with the high resolution previously only used for short-term weather forecasts. This means potential flood and storm risks can be pinpointed to an exact area to enable the government to plan a response.
The Government has confirmed it is using these predictions to prepare for the future, including making plans for flood defences and helping farmers deal with drier summers.
Environment Secretary Theresa Villiers said: “These new local 2.2km projections show in unprecedented detail the extent of the challenge we face. We must adapt to the changes in our climate, but must also continue to take concerted action to reduce our emissions. The data will play a crucial role, helping us make decisions on what more we all need to do to cope with impacts from a changing climate and extreme weather events.”