Climate change means in the future London will have hotter summers and wetter winters. What we consider to be a freak or extreme weather event today is likely to become far more frequent. For example, an extreme weather event that might occur only every once every hundred years now, may occur every 20 years by the end of the century.
The biggest impact on individuals and communities will be the increasing risk of floods, droughts and heatwaves.
Flooding
London is vulnerable to flooding from the Thames and its tributaries; from the sea and from heavy rainfall. A complex system of flood walls, flood gates and drains protect us from flooding. However, with more than 15% of London lying on the former floodplains of rivers, a drainage system over 130 years old, and an increasing tide of concrete covering our gardens and greenspaces, the systems that keeps us dry are being tested.
Flood risk will increase in the future. Climate change will bring wetter winters, more frequent and intense heavy rain, rising sea levels and could make tidal surges from the North Sea higher. London’s growing population and economy will also add to the number of people and buildings at risk.
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Droughts
London is in the driest region of UK. We have enough water for our needs today, but we are already withdrawing more water from the environment than it can sustain. Hotter, drier summers will increase demand and unless we can capture and store the extra winter rainfall, we run the risk of our demands for water exceeding supplies.
Despite having fewer and smaller gardens to water and less cars to wash, we Londoners are a thirsty bunch. We consume more water per household than the national average. Yet if we were to consume less water, we could save money on our energy bills.
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Heatwaves
By the middle of the century, average summer temperatures will be as hot as the extreme temperatures felt in the 2003 heatwave, which killed more than 600 people. A mid-century heatwave will therefore be scorchingly hot, putting those most vulnerable to over heating at increased risk.
The city intensifies the heat of heatwaves. Our buildings, streets and squares absorb energy from the sun during the day and radiate it out as heat during the night. This is known as the Urban Heat Island effect and is the reason that cities are significantly warmer than surrounding rural areas. The waste heat from our energy use adds to this heat to raise temperatures even further, especially in areas that have a lot of buildings close together and little open space. During the 2003 heatwave, the centre of London was 9˚C warmer at night than the greenbelt.
These hot and sticky nights are uncomfortable for us all. But they are dangerous for vulnerable people, such as the sick and the elderly, who need a cool period to recover from the heat of the day and prepare next. This is particularly a problem in London’s most deprived areas where people cannot afford it turn to air-conditioning. The amount of power used by air-conditioning systems creates a further hazard as they can cause power black outs, which again impact upon vulnerable members of the community most severely.
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