Climate change: Warming could increase the cost of flood damage in the United Kingdom by 20%.

Researchers created a detailed “future flood map” of the United Kingdom to simulate the impact of flooding as climate change takes its toll.

It has been discovered that annual flooding damage could increase by more than a fifth in today’s terms over the next century.

This could be reduced if pledges to reduce global carbon emissions are met.

Climate change is expected to have a particular impact on “hotspots” where homes and businesses are at risk.

Even if climate change pledges are met, limiting temperature increases to around 1.8 degrees Celsius, areas such as south-east England, north-west England, and south Wales are expected to see significantly increased flooding.

The new “flood risk map” detail also reveals areas that will be largely unaffected. According to the researchers, this level of detail is critical for planning decisions.

The Bristol University research team and Fathom, a company that assesses flood and climate risk, simulated all types of flooding in the coming decades to create these flood risk maps.

They used data on terrain, river flow, rainfall patterns, and sea level to create a detailed picture of how much flood damage people’s homes and businesses would sustain across England, Scotland, and Wales.

This was combined with Met Office climate projections for the next century.

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The team is also currently modeling flooding in Northern Ireland in order to expand forecasts to include the entire United Kingdom as the climate warms.

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According to the Association of British Insurers, the annual cost of flood damage in the UK is currently £700 million.

Dr Oliver Wing, Fathom’s chief research officer, explained that it was critical to understand how the “flood risk landscape” would change in a warming world because it would be different for each community.

“Our model shows that flood risk is increasing in many places,” Dr Wing said. “Being able to understand the communities where this is likely to occur allows us to make sound investment decisions, whether it’s for flood defense structures, natural flood management, or even moving people out of harm’s way.”

The Calder Valley in West Yorkshire is one of the areas most vulnerable to flooding caused by heavy rain.

According to Katie Kimber of the community volunteer group Slow the Flow, the steep-sided valley meant that run-off swelled the river quickly.

“It happens really quickly – it’s a wave of destruction,” she told BBC News. “Then it’s a matter of repairing the damage – it’s very difficult for people here, both mentally and physically.”

During the 2015 Boxing Day floods, over 3,000 properties in the Calder Valley were flooded, causing an estimated £150 million in damage.

Following the cleanup, Katie and other volunteers began their own flood-prevention efforts with the assistance of the National Trust.

“Essentially, we’re creating speed bumps for the water flowing down the hillside [before it reaches the homes and businesses below],” she explained. “We’re stuffing branches into the channels.”

Members of the community also dig diversion channels to divert and slow down water.

On the new map, Calderdale is a flood hotspot. However, many places are expected to see little change or, in the case of flood risk, actually improve, according to Dr Wing. These areas include large swaths of north-east and central England, as well as parts of eastern and northern Scotland.

According to the scientists, this level of detail is lacking in the government’s current efforts to assess flood risk.

“In general, current government flood maps are not scrutinized by scientists,” Dr Wing said. “Their methods are not transparent.

“And every pound spent on flood risk mitigation is a pound that could be spent on teachers, nurses, hospitals, and schools, so it’s critical that it’s based on accurate science.”

The scientists add that the UK as a whole is “not well adapted to the flood risks it currently faces, let alone any further increases in risk due to climate change”. They are hoping that this detailed forecast will help to change that.

Katie says that better forecasting would be invaluable back on the Calderdale hillside.

“Anything that helps us plan and prepare,” she said. “We want to stay because we enjoy living in this area. As a result, we must confront these challenges, particularly climate change.”

Dr. Wing went on to say that the new, detailed maps could aid in land use planning decisions.

“Those are the things that eventually put people in the path of floods in the first place,” he explained. “We see it all over the world: the most important aspect of flood risk is where people are, not necessarily how the floods are changing.”