Is flood risk really increasing?
The short answer is yes!
In their latest State of the UK Climate Report, the Royal Meteorological Society state that ‘For the most recent decade, UK summers have been on average 15% wetter than 1981–2010 and UK winters have been 11% wetter.’
The size of the future risk is significant too, with the Environment Agency predicting that even with a 2°C temperature rise compared to pre-industrial levels, the following projections can be expected:
Winter rainfall expected to increase by approximately 6% by the 2050s and by 8% by the 2080s, compared to a 1981-2000 baseline.
Summer rainfall expected to decrease by approximately 15% by the 2050s compared to a 1981-2000 baseline.
London’s sea level is expected to rise by between approximately 23cm by the 2050s and 45cm by the 2080s.
River flows will be more extreme. Peak flows are expected to be up to 27% higher in the 2050s, while in the summer months river flows could be 82% lower by as soon as 2050.
Public water supplies are expected to require more than 3.4 billion extra litres of water per day if no action is taken before 2050.
All of this means, that even with effective mitigation being put in place, it is extremely likely that flood risk will continue to increase over the coming years and decades, and we must adapt to ensure that our communities, homes and businesses are resilient to that increased risk.
No, it isn’t.
To understand why flood risk is increasing and the nature of that increased risk, we must first understand that there are several different types of flooding, which can all be seen across the UK.
Groundwater flooding is caused by the water table rising to or above ground level and tends to flow from areas of high land to areas of low land.
River flooding occurs when rivers overflow and burst their banks, due to prolonged or intense rainfall.
Flash flooding occurs where high rainfall events exceed the drainage capacity in an area.
Sewer Flooding is when sewage or foul water leaks from the sewerage system (through pipes, drains or manholes) or floods up through toilets, sinks or showers inside a building.
Coastal flooding, whilst not an immediate concern in the local area, occurs when normally dry, low lying areas are inundated by sea water.
The risk of each different type of flooding differs on a location by location basis and so, the measures which are put in place to tackle flooding must respond to the specific local risks.
A globally warmed atmosphere holds more moisture. As rising temperatures intensifies the water cycle it increases evaporation, resulting in more storms.
The intensity of rainfall depends on how much water the air can hold at a given time. The air can hold up to 7% more moisture for every 1C of temperature rise, so as global temperatures rise, more water is held in the atmosphere and the risk of increased rainfall intensity rises.
In addition to the volume and intensity of rainfall, there are other considerations that can increase the risk of flooding.
River flooding is more likely if a lot of water drains into water courses rather than being absorbed by the ground, which in turn can be affected by vegetation cover or man-made impermeable surfaces. If the ground is less permeable or already saturated by previous rainfall, then more rainfall will reach streams and rivers.
In addition to the permeability of land, the risk of flash flooding and sewer flooding can be impacted by the capacity of drainage systems and is therefore more common in built up areas and where drainage systems may be overwhelmed or inadequate.
We know that the impacts of flooding can be devastating, both causing harm to infrastructure, communities, individual properties and health and wellbeing.
Evidence of this is widespread, with the Association of British Insurers stating that storms Dennis and Ciara (2020) resulted in over 82,000 people claiming for flood or wind damage, with the total cost of repairing homes and businesses expected to exceed £360 million.
Some of the impacts of flooding can be very immediate, with the risks of injury or death, damage to property, destruction of crops, and the spread of waterborne diseases being heightened during and immediately after flood.
Some of the impacts of flood can be longer term, particularly those which affect infrastructure.
Roads, railways and power supplies can become damaged and disrupted, resulting in significant impacts on economic activities. Clean water supply and wastewater treatment facilities can be impacted, resulting in significant risk to human health. The direct effect on production assets, for example in agriculture or industry, can disrupt or cease activity and lead to loss of livelihoods. Communication, education and health care provision can face long term disruption, delaying the recovery back to normal, everyday life.
We looked broadly at adaptation, during our COP26 articles, highlighting that preparing for climate change will require collaboration across society, with local authorities, private and public sectors, infrastructure providers and communities all playing a part.
The UK’s National Adaptation Programme sets out the objectives and actions that will be taken in relation to flooding to:
make sure everyone is able to access the information they need to assess any risk to their lives, livelihoods, health and prosperity posed by flooding and coastal erosion;
bring the public, private and third sectors together to work with communities and individuals to reduce the risk of harm – particularly those in vulnerable areas;
make sure that decisions on land use, including development, reflect the level of current and future flood risk;
boost the long-term resilience of our homes, businesses and infrastructure;
take action to reduce the risk of harm from flooding and coastal erosion including greater use of natural flood management solutions; and
include flood risk as a key feature of adaptation reporting from infrastructure reporting organisations.
We will be looking more closely at local adaptation measures in our forthcoming Climate Change Strategy and will be keen to hear views on how we should approach this task.
Firstly, it is important to understand the risk of flooding where you live. This can be done by following this link and inputting your postcode.
Furthermore, you can sign up for flood warnings. These warn of the risk of flooding from rivers, the sea and groundwater, and provide alerts by phone, email or text when flooding is expected.
There are three levels of flood warning issued – Flood Alert, Flood Warning and Severe Flood Warning with the Environment Agency suggesting the response required at each level.
Locally, we work with partners through the Coventry, Solihull and Warwickshire (CSW) Resilience Team to plan for, prepare for and respond to emergency situations. The CSW Resilience website contains lots more information about how to prepare for and act during a flood.
If you have are concerned about flood risk in your area or have any views on how we might need to adapt to ensure communities are resilient to increased flood risk, then please do get in touch.