Climate Change Raises Thames Flood Risk

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'Urgent Need' to Improve River Defences Highlighted

A new government report has highlighted the likelihood that climate change will significantly raise the dangers of flooding for people living by the Thames.

The Foresight Future Flooding report looks 30-100 years ahead. It outlines the possible risks from flooding, and highlights the decisions that need to be made to protect people, homes, businesses and the environment in the future. A reduction in green house gas emissions and enhanced long-term flood management are needed to control the risk from future flooding.

The report concludes if flood management policies remain unchanged, the risk of flooding increases significantly. Under the most extreme scenario, annual cost of damages could increase 20-fold from the current level.

The Environment Agency, which is already using the data in the report in its work, claims the standard of flood protection of the Thames in London is high but an investment in the flood defences infrastructure of the order of £4bn may be required within the next 40 years.

The coastal flooding of 1953 resulted in over 300 fatalities in eastern England, but London was spared. Nonetheless, the event highlighted the potential threat to London, and resulted in a national flood defence strategy culminating with the completion of the Thames Barrier in 1983. The amount of times the Thames Barrier has been closed has increase significantly over the last decade compared to the first ten years of operation of the barrier. Although scientists suggest this is too limited a sample to draw firm conclusions about the impact of global warming.

By 2100, it is estimated that the Thames Barrier will need to close about 200 times per year to protect London from tidal flooding. Future flood defence needs of London are, therefore, currently being reviewed by the Environment Agency, and will take into account increased peak flows in the Thames, sea level rise, and local changes to tidal conditions.

The risk of flooding in the Tube system is a major and urgent one, and is being taken very seriously by London Underground. The extent of the problem was revealed on 7th August 2002, when intensive rainfall led to flooding of a number of tunnels and closure of stations and parts of the network. LUL is understood to have prepared a report on the possibility of flooding but its conclusions have not been released into the public domain.

Maintaining the current level of flood risk could cost between £20bn to £80bn in total for the whole of the UK over the next 80 years, but the report concludes that a steady increase in investment starting now could make future flood management more affordable – there would need to be an annual increase of between £10m to £30m per year.

The report also found that the effectiveness of drains and sewers in towns and cities could be particularly affected by climate change and increased flooding but this is an area that needs more research.

Sir David King, Chief Scientific Adviser to the Government said: “This Foresight report is the most wide-ranging analysis of future flood risk ever made in the UK. Flooding can have a devastating effect on people’s homes and businesses. There are currently around £200 billion worth of assets and 1.7 million properties in flood risk areas in England and Wales. The scenarios in the Future Flooding report may seem a long way off, but the challenge of increased flood risk needs to be considered now.”

The maintenance of flood defences in London has been a contentious issue in the past. Residents of the Strand-on-the-Green area of Chiswick had to take the local Council to court to get them to maintain flood barriers. No agency was willing to acknowledge responsibility for the maintenance of flood barriers in the area.

The Association of British Insurers have said that they would be withdrawing universal flood cover for properties in flood plains if more was not spent by the Government on flood defences.

March 2, 2004