In a recent analysis from Ordnance Survey, Portsmouth has been identified as the most heat vulnerable city in Great Britain.
Our built-up environment is a major factor in creating an urban heat island, which form where dense buildings, roads and hard surfaces absorb solar heat during the day, keeping cities significantly warmer than surrounding countryside.
Portsmouth City Council has highlighted areas including Somerstown, Portsea, Southsea and Fratton as particularly exposed to urban heat because of extensive hard surfaces and limited vegetation, with some areas of low green infrastructure also overlapping with higher levels of deprivation.
The summer of successive heatwaves has also hit businesses. A report from Verdant Thinking shows that from May to the end of July 2026, the heatwaves had an economic impact of at least £4.4 billion nationally due to reduced productivity and infrastructure and equipment overheating and failing. If heatwaves continue to intensify at the current rate, the impact will be £25.6bn in cumulative losses each year by 2030.
A study on the perceived impacts of the heatwaves showed that 87% of workers reported at least one health-related impact during the week of 22 June 2026, ranging from disrupted sleep and being more tired at work through to a small number of workers reporting more extreme symptoms including dizziness or fainting and a faster heartbeat. During that week, 5% of respondents sought medical attention and around 3% reported an accident or injury in the workplace, with around two thirds of them feeling it was linked to the weather.
Shaping Portsmouth and The Green Partnership are running our second annual Climate Ready Portsmouth forum at Lakeside Auditorium on Wednesday 18th November. At the event we will be exploring the UK’s climate adaptation priorities, place-based resilience, cross-sector collaboration, and business-led investment.
Last year we heard from businesses about how they are already being affected by climate change. With exceptional heatwaves already this year, and an increasing understanding of how this is affecting how people live and work within Portsmouth, Climate Ready 2026 looks to accelerate collective action for a well-adapted place.
The event will include presentations from Southern Water on how they are working in partnership with the council on infrastructure and adaptation, Network Rail reflecting on understanding adaption action, and the MOD on climate risk assessments and how data can inform adaptation planning.
The University of Portsmouth will be presenting on how extreme heat effects employee health, and what 30 years of data tells us about heat in Portsmouth, and Portsmouth City Council will be presenting on the role of nature-based solutions in a well-adapted city.
There will also be networking, exhibition stands, and workshops throughout the day.