Southampton Climate Change Risk & Vulnerability Assessment

Climate impacts and extreme weather events can affect anyone, but some people have the potential to be more affected than others. How badly a person or group will be affected will depend not just on their exposure to the event, but on their social vulnerability – that is, how well they are able to cope with and respond to events like floods and heatwaves. People and communities experiencing multiple causes of vulnerability are the most extremely socially vulnerable.

The main drivers of social vulnerability relate to:

• Personal features of the individual, such as age and health, which affect their sensitivity to climate impacts;
• Environmental characteristics, such as the availability of green space, quality of housing stock or elevation of buildings, which can increase or offset exposure to flooding or heat;
• Social and institutional context, such as levels of inequality and income, the strength of social networks, the cohesion of neighbourhoods and the day-to-day practices of institutions, such as care regimes in nursing homes, which affect people’s ability to adapt.

Which places are disadvantaged?

People are not all affected equally by the same climate-related event, whether heatwaves or floods. Some places are more likely to be exposed to floods or heatwaves. Some places have populations which are more socially vulnerable. How exposure and vulnerability coincide determines the extent of climate disadvantage in an area and where the impacts may be most severe. To effectively tackle climate disadvantage, consideration needs to be given to measures to reduce social vulnerability as well as reducing exposure of the population.

A detailed Climate Risk and Vulnerability Assessment for Southampton was undertaken by Connor Watson of the University of Southampton. This focused on heat and flooding the main impacts influenced by people and place.

Heat

• The summer of 2022 saw unprecedented high temperatures, exceeding 40°C in some parts of the UK, leading the Government to issue heat health warnings equating to a national emergency for the first time.
• Heat related deaths increase and there is significant burden on first responders and the healthcare system. Heatwaves disrupt transport infrastructure and the utility sectors, and cause economic losses at the local, regional and national levels.
• The risks and effects of extreme heat, from increasing prevalence of wildfires and drought to impacts on food security and our ability to live and work indoors or outdoors, are complex
• The impacts of extreme heat are exacerbated by diverse factors including: political and economic constraints; inadequate building and infrastructure cooling; exacerbated urban heat island effects; a lack of understanding about heat-related impacts among the general public and healthcare workers; underlying health conditions of vulnerable populations; and misleading positive messaging about heatwaves in the media.

Vulnerability to heat on an LSOA level according to our index

Flooding

• Tidal – Large areas of the city centre are located within Flood Zones 2 and 3 and are therefore vulnerable to tidal flooding. Impacts from tidal flood risk have been recorded in areas of St Denys, Northam, St Marys and Weston.
• Fluvial flood risk can occur from any of the city’s waterways, including the River Itchen, Test, Tanners Brook and Monks Brook. Areas vulnerable to fluvial flooding which have experienced flooding frequently include Woodmill and Mansbridge.
• Surface water – Southampton is over 80% urbanised meaning there is a significant coverage of impermeable surfaces across the city which limits infiltration and increases the reliance on underground and aging infrastructure. Surface water flooding can occur anywhere and is dependent on the volume, intensity and location of rainfall, with significant impacts seen at Millbrook Road West, Thomas Lewis Way and Central Station to name a few.

Vulnerability to flooding on an LSOA level according to our index

Impacts

• Hotter, drier summers  – Extreme heat is an acute health hazard for those over 65, people with existing health conditions and populations in urban environments-
• Warmer wetter winters  – Can lead to increased damp and problems and diseases from increased blood pressure and common colds to heart attacks and pneumonia.
• Flooding – Health impacts from flooding include the psychological trauma of damage to homes and property, loss of livelihoods and fear of recurrence. At most risk are those who already experience health inequalities, particularly ground floor impacts on vulnerable groups - ability to better protect homes and recover from damage
• Wind / Storms  – Immediate risks to health and wellbeing include damage to infrastructure, facilities and members of the public injured by flying- debris. Roads blocked by fallen trees delaying the emergency services.

Opportunities

• Deliver Southampton Green Infrastructure and Biodiversity Plans to improve access to green and blue space and encourage safe outdoor recreation
• Develop greater public education on the dangers of excess heat or exposure to UV (sun light)- Improved early warning heat alerts to help people prepare for periods of prolonged hot weather
• There may be the potential to reduce the current problems and diseases linked to colder winters
• Develop collaborative working across all health and care providers, the voluntary sector and local government to build resilience and develop emergency response plans
• Assess health impacts of climate change through Health Needs and Impact Assessment (currently being undertaken)

Impacts

• Heat/cold  – Projected increase in the frequency of heatwaves will have a range of impacts on homes, communities and critical infrastructure. New houses which have very high levels of energy efficiency can be susceptible to overheating by ‘keeping the heat in.’
• Flooding / coastal flooding / storm surges / drought  – Present a threat to property and communities, with the potential for both immediate and long-term damage including structural damage from the force of water, subsidence or persistent damp. Risks to dwellings and critical infrastructure across Southampton, including water treatment plants and electrical sub-stations and contamination of water supplies, whilst drought can cause water storages.
• Wind/ storms  – Risk of damage to dwellings and power cuts during extreme events, while wind-driven rain can cause changes to the outer surface of buildings which will lead to more moisture causing damp.

Opportunities

• Early engagement of the voluntary and community sector in planning for emergency response
• Housing retrofit to include installation of passive cooling measures
• Environment cooling – shade, planting, air movement
• Developing and building in resilience by design into new housing estates, eco-communities and infrastructure

Impacts

• Heat - Increases of mean air temperature and increased frequency of heatwaves will have a range of impacts on businesses. This includes:
  • Impacts on employees such as heat exhaustion and heat stroke
  • Impact on stock and inventory (spoiled goods)
  • The knock-on impact of these effects within the wider supply chain
• Flooding – Increased winter rainfall, more river flooding events in winter, potential for more short duration but high impact summer flooding events could limit access to goods and services impacting customers, business impacting customers, business productivity and supply chains
• Wind/Storms – The increasing frequency and intensity of wind and storms will cause building and infrastructure damage, power cuts, supply chain and distribution network disruption from blocked roads and railways which could impact employee access and movement of goods.
• Other – Potential for increased insurance premiums.

Importance of green space

Southampton has 49 parks and 1,140 hectares of open space, including Southampton Common which host over 17 million visitors a year (20% is classified as publicly accessible greenspace), The high population density means that there is a significant deficit of accessible green space per person, particularly in the West of the City where there are no Local Nature Reserves (green spaces for people and nature).

Droughts also risk wildfires such as at Peartree Green in 2022.Climatic changes fundamentally alter natural trends and ecosystems, which can impact the natural systems which we depend on for goods and services, as well as causing decline and loss within ecosystems themselves.

Loss of green space will result in amplifying the climate change hazards of flooding and heat stress which will significantly impact vulnerable groups such as the elderly and under 5s. Green spaces provides mental and physical health benefits and any loss of green space will impact vulnerable groups including children.

Our water supply in Southampton comes from the rivers, so climate change will affect both the quantity and quality of water available

Biodiversity loss

Southampton supports a variety of habitats including coast, mudflats, rivers, wet and dry meadows, heathland, woodland and parkland. A number of these areas are designated as sites of national and international nature conservation importance, including:

• River Itchen Special Area of Conservation (SAC) and Site of Special Scientific Interest (SSSI)
• Solent and Southampton Water Special Protection Area (SPA)
• Lee-on-the Solent to Itchen Estuary Sites of Special Scientific Interest (SSSI)
• Southampton Common Sites of Special Scientific Interest (SSSI)
• Solent Maritime Special Areas of Conservation (SAC)

Biodiversity loss can have significant direct human health impacts if ecosystem services are no longer adequate to meet social needs. Indirectly, changes in ecosystem services affect livelihoods and income (world health organisation). Species populations and habitats have been affected by year to year variations in rainfall and extreme weather events, particularly droughts. Projected changes in these factors could have a major impact on biodiversity and ecosystems.Key urban species have habitats in the Southampton, including bats, bees, badgers, great crested newt and Peregrine Falcons.

The outputs of the climate risk assessment will help the Council, residents, businesses and communities to better prepare for the changes we will see as a result of climate change and understand the role of our environment in developing our responses. We will continue to work with partners, communities and government to develop a strategy showing how we will need to adapt to the changes we are experiencing including:

• Describing how we can help everyone to act in response to our changing climate
• Describe who is responsible for different elements of adaptation planning
• Signpost to information communities can use to develop their own adaptation plans- establish governance for delivery
• Identify suitable ways of monitoring, reporting and communicating climate and adaptation impacts