Risks of extreme weather in Coventry
Risks of flooding
The Environment Agency has 3 categories of flood risk these are based upon the likely probability of an event happening.
Zone 1 which is the largest area of land which could realistically flood under extreme circumstances this is where there is less than 1 in a 1000 year (less than 0.1%) annual chance of a river flood.
Flood Zone 2 is where there is between 1 in 100 to 1 in a 1000 year (0.1% to 1.0%) annual chance of flooding.
Flood Zone 3 is where there is a high probability of flooding of an area with a 1 in 30 to 1 in100 year chance (3.3% or higher) of a flood. The floodplain usually relates to that area of land where there is likely to be greater than a 1 in 30 year chance of it being flooded (3.3% or higher). For this reason, special mitigation measures would have to be put in place in order to let any land in this area to be developed and in many instances there would be a presumption against development.
The latest data from the Environment Agency obtained earlier this year has identified an increased risk of flooding from rivers swelling their banks (Fluvial flooding) the key risk areas for river flooding are Sherbourne, Wyken, St Michaels, Binley & Willenhall or surface water drainage not being able to cope with heavy levels of rainfall (Pluvial flooding) with an increasing incidence of the latter.
Some areas are more prone to flooding whether because people live near a river or in locations that are densely built up where the drains cannot cope with very heavy rainfall and surface water run-off from streets and buildings and other hard paved surfaces. Warmer wetter winters are likely to increase the risk of flooding and rainfall in the summer months will also be more severe with an increasing incidence of heavy thunderstorms between long periods of minimal rainfall or drought. Surface run off in the summer months is more likely to increase when the rain falls on the hard dry ground resulting in an increased risk of flooding.
These areas of flood risk are mapped out for the city and areas on which to focus are identified with a new flood risk management plan.
Extreme heat is affecting our health and wellbeing
The temperatures in cities can fluctuate between different locations by as much as 5oC. The difference between the built-up areas in the city centre, often referred to as the ‘Urban Heat Islands’ and the green areas in the suburbs are noticeably cooler. Parks, gardens, trees, green spaces etc have a vital role to play to help cool urban areas and improve air quality. Coventry has a real need to improve access to green spaces for people, particularly those communities living in the most green-deprived parts of the city to increase resilience during the high temperature periods.
The heat map shows some significant differences in temperature across Coventry depending upon where you live. The more built up an area is the more heat is absorbed whereas green spaces help to reflect the radiation from the sun providing shade which has a cooling effect.
People may be more vulnerable because of their age such as young infants and the elderly and others because that have particular health conditions. Heat and solar radiation can adversely affect air quality to such a degree that it can seriously adversely affect people with circulatory and respiratory diseases such as COPD, asthma and emphysema.
Over the summer of 2023 the UK Health Security Agency estimated there to had been more than 2,000 deaths associated with 5 separate periods of elevated temperatures with people over the age of 85 yrs being particularly susceptible. Five of the top 10 hottest summers on record in the UK have occurred since the year 2000. The NHS’s own ‘4th Health & Climate Adaptation Report’ projects that heat-related deaths could well increase 6-fold by 2050 if we fail to adapt or reduce carbon emissions by the levels required.
Heat also has social effects as well as placing strains on public services. A study of 16,000 different scientific papers revealed that as temperature increases with heatwaves in cities, so does the incidence of crime people become more irritable and aggressive a 10 degree increase in temperature increases the risk of violence by 9%.
Drought and issues of reduced Water Supply
As well as the issue of increased heat during summer, reduced rainfall and an increased likelihood of periods of drought will impact on water supply. Due to the growing pressures on our water supply, the Environment Agency is not able to grant new abstraction licences from businesses during the summer when supply is particularly low. Water is being diverted from other sources to protect rivers and maintain flows and overall supply. Severn Trent is managing higher levels of water demand in the city as our population grows and currently pumps out 2.3 billion litres of treated water per day, which equates to 95 million litres per hour.
During periods of dry weather and drought there is an increased risk of fires. Cities in the UK are facing a growing threat from an emerging phenomenon called ‘firewaves’ where the absence of rainfall for a period of 10 consecutive days or more can result in fires starting in multiple areas of vegetation placing pressure on emergency services. In 2022 the West Midlands Fire Service was called to 4,011 fires in the region, a 71% increase from the previous year. The third week of July that year temperatures exceeded 40oC.
Storms and High Winds
The relationship between storms and high winds to climate change is complex. There is not a clear connection between climate change and wind speed, but there is an increasing incidence in the number of storms (particularly in winter) and the severity of the wind gusts and more extreme weather events often associated with warming climate and periods of high rainfall.
For every 1 oC temperature rise the moisture content of the air rises by 7%. On 10 October 2024, an area in Finham was hit by a small tornado causing significant damage to a localised area with the loss of trees and structural damage to roofs and fencing.