Heat

A changing climate and higher average temperatures combined with increasing urban development and densification is resulting in London getting hotter.

What is the issue with heat?

London is experiencing hotter and drier summers that are further impacted by the Urban Heat Island effect (UHI).  The UHI can cause London to be up to 10’C warmer than neighbouring rural areas.  This is a result of the sun’s rays being absorbed by hard surfaces rather than by vegetation such as trees, plants and grass. Radiation from our hard surfaces is released into the air as heat.  The UHI reduces the ability for cities to cool and impacts on our own capacity to regulate temperature.

We expect London’s population to be 11 million by 2050 and need to build more homes to accommodate our growing population. We must ensure that managing heat risk is considered at all stages of planning and development.  

Heat is impacting us all particularly those vulnerable to excess heat.

Who does extreme heat affect most?

Extreme heat impacts older people, young children and those with pre-existing health conditions such as asthma and/or cardio vascular as well as those with mental health conditions and the disabled. We have a changing demographic in London with an ageing population as well as more under five year olds. This increases the number of people potentially vulnerable to excess heat.

In 2003, 600 (mainly elderly) people died in the London heatwave. London had the highest number of deaths in the country but not the highest temperatures. In 2016, we’ve had three extreme heat days with temperatures over 30'C.

Working together to manage London’s heat risks

We are working with London’s boroughs, public health officials, universities, community groups and others to research and reduce the risk of heat in the city. We want to make living in, working in, and enjoying London a positive experience for all.

Through our planning policy we are managing heat risk in new developments as well as increasing the amount of green space and vegetation to play a part in cooling the city.

We have updated the London-specific Severe Weather and Natural Hazards Framework, which includes a focus on how we respond to, and manage heat risk from heatwaves.

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