Cities in Great Britain most vulnerable to extreme heat revealed

The City of London records the highest built-environment score and the least effective natural cooling of any city. Photograph: Jordan Pettitt/PA View image in fullscreen The City of London records the highest built-environment score and the least effective natural cooling of any city. Photograph: Jordan Pettitt/PA Cities in Great Britain most vulnerable to extreme heat revealed OS index examines which ‘urban heat islands’ suffer the most – and which cope the best with rising temperatures Portsmouth, Leicester, Exeter, Bristol and Nottingham will be among the cities that warm the most , according to research. Analysis from Ordnance Survey (OS) has created a heat vulnerability index for all cities in Great Britain. Portsmouth, which sits on the south coast of England and is home to 208,000 people, is the most vulnerable to extreme heat today and into the future, according to the research from the OS, the Met Office and the data analysis company 4 Earth Intelligence. Concrete, asphalt, buildings and hard surfaces in cities absorb solar radiation during the day and act like giant radiators, holding on to the heat rather than cooling down at night as in more rural areas. Cities can be up to 10C hotter than surrounding areas. Areas most at risk of extreme warming are those with the least tree cover, green space and waterways. View image in fullscreen Portsmouth is the most vulnerable to extreme heat today and into the future, according to the research. Photograph: Peter Titmuss/AlamyThis summer was provisionally the UK’s hottest on record, and the research reveals which cities are suffering now from intense urban heat and which will be among the warmest in future. The research analyses 71 cities granted , Scotland and Wales but excluding Northern Ireland. The OS heat vulnerability index suggests that by 2040 all 71 cities will reach high heat vulnerability. , almost two-thirds could reach the most severe level. Those facing the most severe impact , the City of Westminster, Plymouth, Leicester and Exeter, according to the analysis. Nick Bolton, the chief executive of Ordnance Survey, said: “Cities are where millions of people live, work and spend their everyday lives. “Extreme and sustained heat can affect people’s health and wellbeing, how comfortable our homes and workplaces are, and put additional pressure on transport, energy and emergency services. Understanding how and where this vulnerability is changing depends on an accurate view of how the country is built, based on trusted authoritative data, which is critical for planners, developers and local authorities preparing for a warmer future.” UK ‘built for climate that no longer exists’ and needs urgent changes to survive global heating, report warns Portsmouth is today the most heat-vulnerable city and will remain at the highest level for warming until the end of the century, according to the research.