Landmark report produced by Arup maps London's heat risk across homes, neighbourhoods and essential properties in the wake of climate change, informing the Mayor of London’s plans for resilience.

Global sustainable development consultancy Arup was commissioned by the Mayor of London to produce new research assessing properties and residential neighbourhoods vulnerable to heat risk in the capital. Launching today, the Properties Vulnerable to Heat Impacts in London report looks at which of the city’s ‘essential properties’ such as schools, hospitals, care homes, residential buildings and neighbourhoods would be most impacted during periods of high temperatures.

The report, commissioned by the Mayor of London, also shows there is a direct correlation between a higher heat risk and areas that have greater socio-economic vulnerabilities.

Published alongside the independent London Climate Resilience Review’s interim report commissioned by the Mayor of London, this study will help inform how London and the boroughs prioritise interventions and adaptations needed across the capital to respond to the climate emergency.

Arup’s report references how urban heat is a key challenge facing London. The materials we use to build, like concrete and metal, absorb heat in the day and emit it at night. Commonly referenced as the urban heat island (UHI) effect, factors including heat emitted from cars and air conditioning units, exacerbate the impact and human experience of heat in cities.

Properties Vulnerable to Heat Impacts in London comes after last week’s stark warning from scientists that 2023 was the hottest year on earth since records began. In the summer of 2022, the UK saw its first ever ‘UK Health Security Agency Level 4 heat alert’, and its first ‘Met Office Red extreme heat warning’. Also using Arup’s digital tool UHeat, this publication follows the firm’s previous research assessing the “hot spots” of seven major cities, including London. Modelling the UHI effect in a city, the Urban Heat Snapshot report found that nearly a quarter of a million elderly people and children are living with heat spikes of 4°C in the capital compared to rural surroundings.

The report is the most recent publication produced by Arup for the Mayor of London. Dedicated to supporting the capital with inclusive climate transitions, delivering resilience and equity for all, Arup was previously commissioned to identify retrofit solutions and implementation strategy at scale for the capital, as outlined in the Roofs Designed to Cool report. This was further supported by the firm’s contribution to the Mayor for London’s Climate Resilient Schools programme, which saw the firm lead on bespoke climate action plans for 60 London schools. Arup has since outlined and supported with the implementation of climate action plans for several boroughs including Waltham Forest and most recently Newham.

Summary of report’s key findings

  • Boroughs such as Islington, Hackney and Tower Hamlets show the greater heat risk for schools.

  • Areas towards the outskirts such as Hillingdon, Kingston Upon Thames, Bromley and Barnet show the least heat risk.

  • The hotspot seen in the north of Enfield is attributed to high socioeconomic vulnerability and higher property vulnerability for schools in this area.

  • There is higher heat risk for hospitals in areas towards the centre of London. This includes central boroughs such as Southwark, Tower Hamlets, Hackney, Islington and Kensington and Chelsea. This is down to the UHI effect.

  • Socioeconomic vulnerability is higher towards central and east London especially for the Barts Health NHS Trust, Barking, Havering and Redbridge University Hospitals NHS Trust, Homerton University Hospital NHS Foundation Trust, Whittington Health NHS Trust and University College London Hospitals NHS Foundation Trust. These areas also show a higher heat risk for hospitals.

  • Areas towards the outskirts such as Hillingdon, Barnet, Richmond, Kingston, Sutton, and Merton show the least heat risk. Note that the concentrations of hospitals in these areas are also lower.

Care Homes
  • Boroughs towards central London are considered to have a higher heat risk which is related to the UHI.

  • There is a higher heat risk for residential properties in neighbourhoods in central boroughs such as Hackney, Tower Hamlets, Islington and Camden. These boroughs tend to have a higher proportion of flats, which are considered to be more vulnerable to overheating, compared to outer London boroughs which have a higher proportion of houses.

  • Areas towards the outskirts such as Bromley, Havering and Hillingdon show the lowest heat risk to residential properties.

The report highlights an opportunity to overlay these heat impact datasets with other ongoing climate adaptation programmes, such as flood and drought assessments. Integrating the findings could result in insights into multi-faceted climate risks and drive the development of solutions that can have co-benefits and will ensure that solutions designed to protect against one risk factor do not inadvertently cause issues with another.

Download the report

Properties Vulnerable to Heat Impacts in London

What they say

London is getting hotter, with the design of our urban capital contributing to how heat impacts different spaces. We produced this report to quantify which areas and properties are most vulnerable. It is vital that these findings inform GLA's efforts and broader policy-making so that meaningful interventions can be put in place to protect Londoners in buildings most at risk of overheating. At the same time, London needs a holistic approach to reducing the impact of the different consequences of climate change.

Damien McLoud

Director, Arup

For some time now we’ve known London is getting hotter – and we need to urgently future-proof the capital against the impacts of a changing climate. The Mayor commissioned this report to help us prioritise the areas and public services which most need adaptation in the face of extreme heat. It’s unacceptable that people living in London’s most deprived areas are the most vulnerable to overheating. This week the Independent London Climate Resilience Review, which was commissioned in June, published its interim report detailing the steps we are urgently taking to protect all Londoners from the impact of climate change, now and in the future. If we make bold choices now, we can build a better, greener and safer London for all.

Shirley Rodrigues

Deputy Mayor of Environment and Energy, Greater London Authority