Experts have produced a fearsome "future flood map" of Britain after sounding a grim warning as climate change takes its toll.
A new study shows that annual damage caused by flooding in the UK will rise by nearly a quarter over the next century unless international climate targets are met in full.
The research, based on Met Office projections of the likely impact of climate change, shows national flood losses can only be avoided if all countries - including the UK - stick to their Net Zero promises made at COP 26.
If these ambitious promises aren't honoured, scientists warn flooding costs could grow by up to 23 per cent over the next century.
The study also highlights specific regions where flooding will increase most dramatically, including north-west and southeast England, central Scotland and South Wales - as well as in densely populated cities across the UK, which could see damages rise by a quarter over the next century.
The study was led by the University of Bristol and global water risk modelling leader Fathom, and is the first-ever dataset to assess flood hazard using the most recent Met Office climate projections, which factor in the likely impact of climate change.
The findings show that forecasted annual increases in national flood losses - defined as physical damage to properties and businesses - due to climate change in the UK can be kept less than five per cent above recent historical levels.
However, the researchers warned that this was only possible if all countries stood by ambitious pledges signed at COP26, held in Glasgow in November 2021, and that countries which made further Net Zero commitments - including the UK - achieve these on time and in full.
If these pledges aren't met, the study shows annual flooding costs could balloon across the UK by between 13 and 23 per cent over the next century.
Paul Bates, the study's lead author and Professor of Hydrology, insisted the new data needed to be taken 'very seriously'.
Prof Bates, who is also Chairman of Fathom, explained: "For the first time, this flood model gives us a more accurate and detailed picture of the impact of climate change on the risk of flooding in the future across the UK.
"The results are a timely warning to the country's political leaders and business sector that global commitments to significantly reduce carbon emissions must be taken very seriously, and ultimately take effect, in order to mitigate increased losses due to flooding."
The estimates of historical flood risk, based on actual river flow, rainfall, tide-surge observations and climate model projections, correlate with data on flood losses from the Association of British Insurers and shed new light on the financial toll of flooding.
Though previous studies have shown that historical financial flood losses were three times less than Government estimates, this is the first time losses have been replicated by a computer model.
Dr Oliver Wing, a co-author of the study and Chief Research Officer at Fathom, warned flood risk had to be given bigger priority across the world.
Dr Wing, who is also an Honorary Research Fellow at the University of Bristol, said: "This study, which harnesses new data and the very latest modelling techniques, validates Fathom's UK Flood Map and has given a new level of insight into the impact of climate change on flooding in future.
"The modelling provides clear evidence that flood risk needs to be a bigger international priority and that current governance doesn't go far enough.
"While the majority of the nation's future flood risk already exists today, it is strongly in the UK's interest to exercise leadership in global carbon emission reduction efforts, both by example and as part of global diplomatic initiatives."
The study's sophisticated new data also identifies which regions will bear the brunt of future flood damage - even if the best-case scenario, in which global warming is limited to 1.8 C, is achieved.
The areas predicted to be most affected by future flooding include southeast and north-west England, south Wales and Central Scotland.
Densely-populated cities such as London, Cardiff, Manchester, Glasgow, and Edinburgh could also see huge increases in annual flood damage of up to 25 per cent.
But central and north-eastern regions of England, as well as Eastern and Northern Scotland, are predicted to change very little from the present day under the new model.
Prof Bates added: "Although the most optimistic climate scenarios see only modest increases in flood losses at a national level, these new data demonstrate how this conceals dramatic variations across the country - with some places seeing large changes and others very little.
"This is a result of changing patterns of future rainfall, river flow and sea level rise, and this leads to the regional differences we predict.
"We found that flooding increases most in places where risk is already high now, so the best thing we can do to prepare for the impact of climate change is to strengthen flood management in currently at-risk areas.
"This will bring immediate economic and social benefits, as well."
Prof Bates' research team plan to produce future analysis for other nations across the world, in order to further understand how climate change will affect global risks.
