Moderate the urban heat island

The urban heat island effect can make cities several degrees warmer than surrounding areas and this will be exacerbated by climate change.

The biggest difference is in night time temperatures where the heat stored by hard surfaces, roads, roofs and walls is only slowly released. This creates an island of warmer temperature which is very oppressive during hot summers.

Hotter summers can decrease human comfort, increase heat stress and in extreme cases result in increased mortality. In the heatwave of 2003, there were up to 35,000 additional deaths across Europe and 3,000 additional deaths in the UK.

According to research by the Hadley Centre, by 2040 more than half of summers will be warmer than 2003 and by 2100 summer temperatures similar to 2003 will be classed as cool.

Green infrastructure can also help mitigate climate change by reducing energy demand for cooling buildings. Modelling work in Greater Manchester suggested that if we increase our green cover in towns and cities by 10 per cent, we can keep surface temperatures at current levels despite climate change.

However, evaporative cooling is dependent on vegetation having an adequate supply of water. This will be especially true during droughts, when irrigation will be required. It is important that sustainable water management be linked to maintaining functional green infrastructure, such as capturing and storing rainwater till needed for irrigation – this can have the added benefit of alleviating flood risk from heavy rainfall.