Cities in Great Britain most vulnerable to extreme heat revealed — SkimNews
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- Ordnance Survey partnered with the Met Office and 4 Earth Intelligence to build a heat vulnerability index scoring all 71 royally-chartered cities in Great Britain on a 1-5 scale combining observed temperatures, built-environment structure and climate projections.
- Portsmouth ranks as the most heat-vulnerable city today and is projected to remain at the highest level through 2100, with local leaders flagging Somerstown, Portsea, Southsea and Fratton as exposed hotspots where limited green space overlaps with deprivation.
- Leicester shows the largest projected rise in the rankings, climbing from 10th currently to fourth by the end of the century, while Exeter, Nottingham, Bristol and Brighton and Hove also enter the top 10.
- By 2040 all 71 cities will reach high heat vulnerability, and by 2100 almost two-thirds are projected to reach the most severe level on the OS index.
- The City of London records the highest built-environment score and least effective natural cooling of any city, with Westminster ranking third overall today and second in both future periods behind Portsmouth.
- A study commissioned by the Mayor of London puts the total economic cost of the 2022 London heatwaves at £1.5bn, covering productivity losses, health impacts, education disruption, energy demand, transport and emergency services.
- Milton Keynes ranks 69th of 71 for heat vulnerability today, with 46 sq km of natural surfaces against almost 40 sq km of hard made surfaces — the most effective natural cooling of any city in the analysis.
Why it matters: The OS index gives local authorities a street-by-street heat-risk scorecard that will steer where new tree cover, cooling refuges and emergency-response planning are directed across Britain. It projects every one of the 71 cities reaching high heat vulnerability by 2040 and nearly two-thirds reaching severe by 2100 — a trajectory that, based on the £1.5bn cost of the 2022 London heatwaves alone, places tens of billions in potential economic damage squarely on planners and developers over the next two decades.
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