How prepared is London for heatwaves, drought and flooding?

The second Preparing London for Change lecture examined the consequences of more severe weather, revealing that collaboration is key.

From left to right: Cassie Sutherland, GLA, Samina Khan, EA, Dave Wardle, ICE London & South East, Vince Dardis, TfL, Alex Nickson, Thames Water.
From left to right: Cassie Sutherland, GLA, Samina Khan, EA, Dave Wardle, ICE London & South East, Vince Dardis, TfL, Alex Nickson, Thames Water.

Heatwaves, droughts and flooding are all increasingly likely as climate change causes wetter winters and warmer, drier summers.

How do we deal with this and what can a city like London, with more than 8 million people living in it, do to prepare for such situations?

These were the questions put to four experts at the second Preparing London for Change lecture chaired by ICE London and South East Water Panel Chair Dave Wardle on 15 May.


Vince Dardis from TfL spoke about the growing threat of heatwaves to the London Underground system. Trains pump out heat with around 79% absorbed by tunnel walls, 10% removed by ventilation and 11% remaining in the tunnel. However, as temperatures increase in the summer heatwaves can make commuters even more uncomfortable, potentially leading to illness.

Vince described the measures that TfL are taking to ensure the Underground is able to cope, including public information, making improvements to rolling stock and liaising with the emergency services.

Keeping trains moving is one of the most important tasks for TfL as stalling trains can lead to further health incidences if carriages become too hot.


Alex Nickson from Thames Water explained how London would manage severe drought situations. It takes two consecutive dry winters to cause a drought in London but as demand grows the capital will become increasingly prone to water shortages. By 2045, there will be a 418m litres a day deficit in water supply unless action is taken.

Under Thames Water's drought plan measures are set out to manage the growing severity of a drought. The first phase would be a media campaign to highlight the need to preserve water, followed by hosepipe bans. In the most serious of cases, Cobra, the Government's crisis response committee, would step in and the water pressures could be lowered to ration the amount of water being used.

Options being considered to increase water supply in the south east include a new reservoir, water transfer from the River Severn or water reuse such as desalination. These options are being considered alongside measures to reduce the demand for water, such as smart metering.


Samina Khan from the Environment Agency set out the River Thames scheme to reduce flood risk between Datchet and Teddington, the largest area of undefended floodplain in England. The scheme would also create over 40 hectares of habitats to improve biodiversity.

The scheme would involve largescale engineering works to construct a new flood channel 30-60mwide in order to protect the 15,000 homes and businesses in the area. Without the scheme damages from a major flood could exceed £850m (£2bn by 2055 taking into account climate change).

Samina set out the need for further funding from partners in the region to ensure the scheme was constructed. Currently, £250m of funding has been secured but an additional £225m is required.

London's response

Cassie Sutherland, the GLA's Environment Programme Manager, gave an overview of the steps City Hall is taking to protect London against more extreme weather.

For example, the upcoming London Environment Strategy where Mayor Sadiq Khan will set out his policies on climate change and sustainability. This will include commitments to 'good growth' where the built environment is utilised to provide benefits to the environment.

Current initiatives like the SuDs action plan are also helping to improve the capital's resilience. The plan shows how opportunities to retrofit sustainable drainage can be taken so that buildings like schools, hospitals and offices can reduce surface water runoff.

Cassie concluded with the need for greater collaboration between different sectors to improve London's resilience. She spoke about the benefits of organisations like London Resilience and the London Climate Change Partnership in breaking down these industry silos.

Preparing London for Change

The last lecture of the Preparing London for Change series will look at resilience and placemaking, where adaptation combines with regeneration, on 17 July.

Book your place today