Urban heat risk posing a threat to elderly in cities

Our cities are getting hotter. Extreme hot weather events are happening more frequently and as a result London and other major cities around the world face significant risks. How do we develop approaches to understand and address urban heat risk?

A new report from Arup identifies the factors which contribute to urban heat risk, and has developed approaches and responses to address these factors. By 2030, 60% of the world’s population will be living in urban areas. For some people living in these areas, hot weather can be a real threat. There are four main reasons why hot weather poses an increasing risk to the health and comfort of people in London and other cities.

The Arup Urban Heat Risk Mapping and Visualisation project has identified the factors which contribute to urban heat risk, and has developed approaches and responses to address these factors.

• Climate change is resulting in higher average temperatures and more extreme hot weather events.
• The prevalence of the urban heat island (UHI) effect reduces the ability of areas of the city to stay cool or cool down at night during hot weather. 
• A changing demographic, particularly an ageing population as well as more under five year olds, increasing the number of potentially vulnerable people.
• Increasing urban development and densification which contributes to the UHI effect, puts pressure on existing open green spaces and green infrastructure which provide essential shade and cooling for cities.

As a result of these factors, hot weather is causing more than just discomfort. As temperatures rise in cities, so do the number of heat related illnesses, emergency call outs and, in some cases, deaths.

Decision makers in London including housing and public health professionals, planners and developers and local politicians need to be well-informed about the risks of hot weather and understand the approaches to protect the most vulnerable people. In the absence of any approaches to address urban heat risk, heat-related deaths in London could more than double by the 2050s.

In the UK, heat-related stress currently accounts for ≈1,100 premature deaths and <100,000 hospital patient-days / year.

Key features

• Simplifies the main factors which contribute to urban heat risk into three categories; the triple risk index. ?
• Enabled the mapping and visualisation of relevant data sets at a range of spatial scales – city, borough, neighbourhood – highlighting 'triple risk' areas where physical factors coincide with building forms conducive to heat risk and vulnerable people.?
• Recommends approaches and responses to manage and mitigate against urban heat risk.?
• Provides key messages for decision makers in London