Seasonal health and climate change resilience for ageing urban populations: the development of vulnerability indices for selected cities and prioritis

t is widely recognised that climate change related alterations in the frequency and intensity of extreme weather events are likely to pose an increasing risk to public health. This is especially the case in major cities that have large numbers of elderly people who are potentially more vulnerable to extreme weather events. Elderly people comprise a rapidly growing and vulnerable group of society within which large populations of chronically and mentally ill, as well as isolated or homeless people exist. It is within this context that we consider the impact of extreme weather events on the urban ageing and elderly population.
Globally more people than ever are living in cities than in rural areas. The turning point was in 2007 when more than 50% of the world's population was considered to live in urban areas; by 2030 this is expected to rise to 60%. The types and impacts of extreme weather events experienced in a particular city will vary based upon the climate zone within which it located and its geographical features. Therefore, it is important to have a good understanding of the city-specific climate data and geospatial information at a range of temporal and spatial scales.
In parallel, over the past 100 years we have seen an unprecedented increase in life expectancy: people are living longer than at any point in history. This can be considered a modern global phenomenon. It is expected that by 2050, 22% of the global urban population will be over 65 years old. Elderly people over 65, especially those over 75 and living alone, are amongst the most vulnerable to the risks associated with extreme weather (especially extreme heat and cold). Often, but not always, they lack good health, mobility, access to technology and social networks and they also have a different physiological response to, for example, extremes in temperature than the younger, able-bodied, population who are more mobile and often have larger and more varied social networks. Epidemiological work has found that age (people over 65 years old) is one of the most significant determinants of heat-related health risk. Further risk factors include a propensity for dehydration, malnutrition or obesity in this section of society. Evidence has shown that during and after an extreme heat event, the elderly population tends to be amongst the most at risk.
Our project 'Seasonal health and climate change resilience for ageing urban populations: the development of vulnerability indices for selected cities and prioritisation of targeted responses', forms part of the Arup Global Research Challenge. This project aims to work collaboratively with multi-disciplinary networks of health and climate change experts from academia and the private sector, local government and NGOs to review and compare different datasets and methods of vulnerability index development, and to define and agree upon a process to develop local vulnerability indices for three global cities: London, New York and Shanghai. Our stakeholder team consists of representatives of urban planning and public health policymakers, local government and NGOs from the three case study cities. This work will represent an advance in the current research and practice as it will focus primarily on older populations, and will build upon extensive work undertaken in London and transfer it to New York and Shanghai.

Our stakeholder team consists of representatives of urban planning and public health policymakers, local government and NGOs from the three case study cities. As part of our dissemination strategy, multiple paths will be pursued to maximise stakeholder benefit:
- A number of presentations in collaboration with our team and other partners will disseminate the findings of the project to our stakeholder team.
- Interested parties will also be able to access the data underlying the climate risk vulnerability mapping work for each one of the three case study cities, and provide insights and feedback regarding their specific requirements throughout the duration of the project. This will ensure that the direction of the project is in line with stakeholder needs.
- In addition to these outputs, a pack including best practice guidance and case studies will be produced that can be used by city and neighbourhood authorities to assess and prevent climate vulnerability, thus enabling more informed policy decisions.
In particular, the project outputs could assist urban planners and local government seasonal health policymakers identify urban neighbourhoods and populations at risk during extreme weather events, prioritise risk mitigation actions and take the necessary steps to prevent such risks in the long term through interventions at the invididual building and urban scale.
For example, the Mayor of London's Climate Change Adaptation Strategy 'Managing risks and increasing resilience' highlighted the research need "to map overheating risk and identify 'triple jeopardy' areas where urban heat island intensity, poor thermal performance of the housing and high personal vulnerability combine to create a high risk hotspot. [...] The Mayor will then work with partners to define who (e.g. a Registered Social Landlord) is best placed to manage the risk (for example by local urban greening, or building retrofitting measures)."