Climate Change Data

Created: 31 October 2024 Updated: 17 September 2025

We have created information which indicates the possible impacts of climate change on future risk. We have selected the scenarios from our Flood risk assessment: climate change allowances considered most relevant to the expected uses of the data. Our allowances include anticipated changes to: 

• Peak river flow 

• Peak rainfall intensity 

• Sea level rise 

• Offshore wind speed and extreme wave height 

The climate change allowances are based on the latest UK Climate Projections (UKCP18) from the Met Office, using the Representative Concentration Pathway (RCP) 8.5.  

Allowances are based on percentiles. A percentile describes the proportion of possible scenarios that fall below the chosen scenario. For example, the 95th percentile is the point at which 95% of the possible scenarios fall below it, and 5% fall above it. 

Our Flood risk assessment: climate change allowances include several different allowances reflecting the range of possible future climates. They also provide allowances for different periods of time, acknowledging that some users will want to look further into the future than others. The periods of time vary for each source of risk because equivalent datasets for each source are not always available.  

We have chosen the period of time and percentile for each dataset according to its purpose. 

Check Your Long-Term Flood Risk

Check Your Long-Term Flood Risk is aimed at supporting individuals, communities and organisations making short- and medium-term decisions to manage future flood risk. We have therefore chosen: 

• the ‘Central’ allowance (50^th percentile) for the 2050s epoch (2040-2069) for risk of flooding from rivers 

• the ‘Higher Central’ allowance (70^th percentile) for risk of flooding from the sea, accounting for cumulative sea level rise to 2065 

• the ‘Central’ allowance (50^th percentile) for the 2050s epoch (2040-2060) for risk of flooding from surface water.  

For flood risk from the sea, we use the Higher Central estimate reflecting significant uncertainties in climate science for future sea level rise. These approaches are in line with standard guidance for flood and coastal decision making. 

‘Risk of flooding from rivers and the sea’ shows the chance of flooding from rivers and the sea taking account of flood defences and the condition they are in. For risk relating to climate change, we assume no changes in flood defences or condition. 

Flood Map for Planning and additional flood risk datasets

Flood Map for Planning is aimed at supporting planners and developers making long-term decisions about the location and design of development and the use of land. Such decisions need to account for the full anticipated lifetime of the development being planned. We have therefore chosen: 

• the ‘Central’ allowance (50^th percentile) for the 2080s epoch (2070-2125) for risk of flooding from rivers  

• the ‘Upper End’ allowance (95^th percentile) for risk of flooding from the sea, accounting for cumulative sea level rise to 2125.  

We have chosen time periods appropriate for long-term planning. We have chosen the Upper End allowance for flooding from the sea reflecting significant uncertainties in climate science for future sea level rise, and in line with our precautionary approach for planning and development.

These allowances are also used for our supporting ‘Rivers and Sea flood risk extents’ datasets.

For risk relating to climate change for the ‘defended’ scenario, we assume no changes in flood defences and that they will operate effectively. For risk relating to climate change for the ‘undefended’ scenario, we ignore the benefits of any existing flood defences. 

National Coastal Erosion Risk Map

The National Coastal Erosion Risk Map and the Shoreline Management Plan Explorer website are aimed at supporting coastal managers and planners making short and long-term decisions to manage current and future coastal erosion risk. This information is also available to the public.

The coastal erosion projections use coastal management approaches and time periods from the Shoreline Management Plans.   

Sea level rise due to climate change influences the erosion projections by increasing the erosion rates and decreasing the lifespan of coastal defences.   

Erosion risk zones are shown on the National Coastal Erosion Risk Map for two future climate scenarios:   

• the ‘Higher Central’ allowance (70th percentile) from now to 2055 and from now to 2105.  

• the ‘Upper End’ allowance (95th percentile) from now to 2055 and from now to 2105.  

We have chosen the Higher Central and Upper End allowances for coastal erosion projections reflecting the significant uncertainties in climate science for future sea level rise. These approaches are in line with standard guidance for flood and coastal decision making.