Responding to future risk: flooding
From Future of Local Services to the Public
Contents |
Summary
Over £200 billion worth of assets around British rivers and coasts and in towns and cities are at risk from flooding and we are all vulnerable to the disruption of transport and power when a major flood occurs. The risks are set to increase over the next hundred years due to changes in the climate and in society.
Two key messages come out of a 2004 report on the future of flooding by Foresight. Firstly, continuing with existing policies is not an option – in virtually every scenario considered, the risks grow to unacceptable levels. Secondly, the risks need to be tackled across a broad front. Reductions in global emissions would reduce the risks substantially. However, this is unlikely to be sufficient in itself. Hard choices need to be taken - either to invest more in sustainable approaches to flood and coastal management or to learn to live with increased flooding.
Impacts
- Nearly 2 million properties in floodplains along rivers, estuaries and coasts in the UK are at risk of river or coastal flooding.
- If flood-management policies and expenditure are unchanged, annual losses would increase under every scenario by the 2080s. The amount of that increase could vary from less than £1 billion to around £27 billion.
- Towns and cities will be subject to localised flooding caused by the sewer and drainage systems being overwhelmed by sudden localised downpours. The potential damage could be huge.
- Damage from costal erosion is set to increase by 3 - 9 times by the 2080s, although the worst case (£126 million per year) is still much less than current flood losses (£1 billion per year).
- The number of people at high risk from river and coastal flooding could increase from 1.6 million today, to between 2.3 and 3.6 million by the 2080s. The increase for intraurban flooding, caused by short-duration events, could increase from 200,000 today to between 700,000 and 900,000.
- Increased flooding could bring both opportunities and threats to the environment. Saltmarshes could benefit from abandonment of uneconomic coastal farmland under some scenarios, but habitats such as coastal grazing marsh are threatened under every scenario.
- Many powerful drivers will influence future flood risk - climate change, socioeconomic factors that influence the vulnerability of people and value of assets at risk, and governance issues such as stakeholder behaviour and environmental regulation.
Relevance
- No single response can adequately reduce the considerable risks that have been identified. An integrated portfolio of responses could reduce the risks of river and coastal flooding from the worst scenario of £20 billion damage per year, down to around £2 billion in the 2080s.
- Between £22 billion and £75 billion of new engineering is required by the 2080s. The sensitive implementation of responses can ensure that flood management does not have damaging social or environmental costs.
- An integrated approach, including but not limited to engineering, to intra-urban flooding will be vital.
- Governments - central and local - must think about whether they will: accept increasing levels of risk of flooding; seek to maintain risks at current levels; seek to reduce the risks of flooding.
- If reducing climate change is part of the strategy for managing future risks, it could make the task we face substantially easier.
- Changes in risk and the costs of flood management are particularly uncertain in the case of intra-urban flooding. It needs to be decided how much to invest in better modelling and prediction of flooding in urban areas to ensure that authorities can plan ahead more effectively.
- Planning needs to address: how we use land, balancing wider economic, environmental and social needs against creating a legacy of flood risk; how we manage the balance between state and market forces in decisions on land use; whether to implement societal responses with a longer lead time or rely increasingly on bigger structural flood defences with potential economic, social and environmental costs; how much emphasis to place on measures that are reversible and those that are highly adaptive.
- Responses need to be matched with the scale of future risks: governance to support the concept of a portfolio of responses to increasing flood risk/to allow its integrated implementation; adaptability in the portfolio of responses/its governance arrangements; investment for future flood and coastal management, to promote long-term solutions, appropriate standards and equitable outcomes; market mechanisms and incentives to manage future risks; science and technology in the development of long-term policies in flood-risk management; periodic reassessment of the long-term strategy for managing flood risk to take account of new scientific data and to enable it to be adapted to an evolving future.
- Government should also consider whether it should invest more to ensure better informed decisions on long-term flood management, do more to join up different areas of science, ensure a sufficient supply of engineers for flood management in the future and ensure that they have a broad understanding of different areas of science?
Innovations
References
Foresight (2004) Future Flooding, available online at http://www.foresight.gov.uk/Drumbeat/Flood%20and%20Coastal%20Defence/executive_summary.pdf
