The London Assembly has called for Thames Water to provide its Environment Committee with an assessment of its drainage network’s ability to deal with heavy rainfall events.

The London Assembly Environment Committee report, ‘Come rain or shine: London’s adaptation to the risks of severe weather’ is warning that thousands of seasonal deaths during moist winters and scorching summers are expected to become the norm.

According to the report, London is not well prepared for the risks of severe weather - and climate change is likely to make things worse. The most vulnerable in society, particularly the elderly, are at the greatest risk from the effects of a changing climate and severe weather events.

There are due to be twice as many days over 26°C in London by the 2020s. In the 2003 heatwave, 600 Londoners died, with many more affected or hospitalised by heat-related illnesses.

Floods also pose a major risk, not only causing damage to property but putting lives in danger. London’s drains were built in the expectation of a severe rainfall event (more than 45mm of rain in a day) once every 30 years, but London now experiences this once every 6 years.

The report makes a number of recommendations to ensure London can adapt, including:

• The Government should update building standards and regulations regarding climate adaptation, especially to keep homes cool in hot weather.
• Thames Water should provide the Committee with an assessment of its drainage network’s ability to deal with heavy rainfall events.
• The Mayor should press for standards and regulations to promote flood-resistant buildings in flood-prone areas, especially those identified in recent work by Drain London.
• The Mayor should produce an action plan update to the Climate Change Adaptation Strategy, showing how his own programmes will ensure London is better prepared for severe weather.

Stephen Knight AM, Chair of the Environment Committee said:

“The Committee has heard from leading climate change experts and the message is clear – London’s summers are getting hotter and drier, and winters milder but wetter. Within this trend, however, heatwaves, droughts, storms, flooding and cold snaps are all becoming more frequent.

“This has implications for the way in which we build the large number of new homes needed in London. The Mayor’s programme of retrofitting, where existing homes are made more energy efficient, is also not hitting its targets.”

“The Committee recognises that whilst it’s not possible to completely eliminate the risks associated with severe weather, measures can certainly be taken to help London ride out the storm when it hits.”