The Future Impacts of Climate Change

Communities are the people living and working in, and visiting, the area. They include businesses and supporting infrastructure, and the natural and cultural environments which make the area unique.

Building communities which are resilient to climate change requires people to be kept informed, motivated and able to respond when required. When agencies plan for responses before, during and after flood incidents, they rely on the most up-to-date information. In this way, resources and assistance required by communities can be provided where and when they are needed.

A key outcome of the plan is to achieve a level of resilience to flood risk which has been agreed with democracy at the heart of decision making, where you as the communities, businesses and stewards of the environment, heritage and culture have had a say in producing the plan. The overall approach to flood risk management can be adaptive, i.e. to plan now, so that we are best placed to adapt as the climate changes. Many of the actions required, at least initially, may be relatively small and implemented in stages. This enables us to seek actions which are the best fit for each place but which, together, give a unified response.

This approach also enables the partnership to be fair in how flood risk management responses are justified and paid for.

Norfolk and Suffolk have a diverse economy, and there are ambitious plans for growth in and around the plan area. Well-managed flood risk can inspire confident investment and job creation which supports sustainable growth. In particular, biodiversity is locally, nationally and internationally important and one of the key foundations for continued sustainable growth.

The BFI plan can manage risk in line with our changing nature and support others to act sustainably. For example the BFI plan could:

• Support farmers and local agriculture - see Point 1 in the map opposite for more information and to discover the extent of agricultural area within the BFI area
• Support sustainable building development - see Point 2 in the map opposite for more information
• Support tourism - see Point 3 in the map opposite for more information
• Support habitat and biodiversity - see Point 4 in the map opposite for more information

Sea level has already risen around the UK coast by about 0.16 m since 1900, and will rise more rapidly through the 100 year period of the BFI Plan, and beyond. If we look out to sea on a calm day in 20 years’ time, the level is likely to have risen by between 0.19-0.22 m, compared with average levels between 1981-2000.  In 50 years’ time, the sea is expected to be 0.33-0.46 m higher and, in 100 years’ time is anticipated to be 0.54-1.02 m higher.  It is also possible that we need to prepare for a sea level rise of up to 1.5 m by the end of the plan period. As most of the land in the plan area is low lying, a rise in mean sea level of around a metre would make more land much harder to drain on a daily basis.

The risk of coastal flooding will increase because any given tidal surge will occur on top of a higher sea level. Increasing risk comprises not just the potential for damage, but how frequently it could occur. For example, at the mouth of the River Yare, a peak storm level which is only likely to occur with a 0.1% chance in any year today, could be 30 times more likely to occur (i.e. an annual chance of 3%) when sea levels have risen by a metre.

The total amount of rain falling in any year is expected to decrease slightly in the next 100 years. However, seasonal patterns of rainfall will become more pronounced, with total rainfall substantially increasing in winter and decreasing in summer. In both seasons, it is expected to rain less often but, when it does, it will rain with greater intensity. Particularly in our urban areas (e.g. Great Yarmouth), greater intensity rainfall could mean more surface water flooding.

Winters in 20 years’ time are expected to have 5-7% more rainfall, in 50 years’ time 7-15% more and, in 100 years’ time, 11-29% more than used to fall in winters between 1981 and 2000. Summers, on the other hand, will likely have 15-18% less rainfall in 20 years’ time, 20-30% less in 50 years’ time and 27-51% less in 100 years’ time, compared with 1981-2000.

It is possible that even greater changes in rainfall patterns could occur. However, even the minimum expected changes of 11% more rainfall in winter and 27% less rainfall in summer will require significant changes to how water is managed. For example, it is possible that river flows in winter will increase by 20%, whereas flows in summer will decrease by 40%, with implications for the likelihood of flooding and water available for irrigation, for example.

As well as rising sea level making regular drainage from low lying land and watercourses more difficult, the increase in high tide levels and intensity of rainfall-runoff into rivers, all increase the risk of flooding incidents.

The map opposite shows in light yellow that approximately 30% of the BFI plan area is currently at risk of tidal and/or fluvial flooding from an incident which has a 5% chance of occurring in any year. This map does not suggest that the whole light yellow area shown would be flooded at the same time, but that any location in this area is at risk of flooding. The same map also shows in dark yellow how this ‘at risk’ area could expand, when mean sea level (MSL) has risen by just over one metre, and river flows have increased by 20%. This increase is anticipated even with the existing infrastructure continuing to operate.

Towards the north of the BFI Plan area, locations which are at risk of flooding in today’s climate in an event with an annual chance of 5% include the River Thurne around Hickling, Horsey and Potter Heigham, areas near the River Bure upstream of Upton Marshes, and in the River Ant catchment upstream of its confluence with the Thurne and Bure. In the River Yare catchment, Limpenhoe Marshes and areas upstream of Buckenham Marshes, as well as along the River Chet to Loddon, are at risk. In the centre of the plan area, low lying land south of Breydon Water, Haddiscoe Island and along the Cut is at risk. Further south, land at risk is near the River Waveney upstream of Oulton Marshes and particularly upstream of Beccles.

Some of these areas at risk are particularly low lying. However, the risk of flooding is more strongly influenced by the heights of embankments near the rivers. In many cases, these heights are maintained so that the river levels under normal conditions, and the pattern of flooding which has been a long time feature of the area, are continued. The system is controlled in this way to, for example, provide freshwater to wetland areas, maintain navigation depths and to store water away from locations where flooding could cause more damage. In larger flood events in today’s climate, and as suggested by the much larger areas at risk with +1 m of sea level rise, this system could be overwhelmed as the embankments overtop. The 5% flood event map therefore provides an illustration of areas at risk of flooding, but there are many complexities the map alone cannot portray.

The map opposite shows a similar comparison, this time for a fluvial and/or tidal incident which has a 1% chance of occurring in any year.

By 2120, it is possible that the majority (70%) of the BFI plan area is at risk of flooding in fluvial and/or tidal incidents which have a 5% or less chance of occurring in any year. It is only the ground levels of the plan area rising towards the edges of the floodplain, which keeps area at risk of flooding from expanding further.

The internationally and nationally designated habitats, and the range of species which are either unique to the area or have their largest UK populations here, underline the importance of biodiversity. However, climate change could alter some of the area’s special characteristics. For example, freshwater areas could be flooded more frequently, for longer, and with saline or poor quality water. These impacts could alter habitats and vegetation, which mean new species are established, whilst others may relocate, and some are in danger of being lost.

There are opportunities for new habitats and species, and particularly for birds due to their mobility. For example, the shallow lagoon and reedbed area of Hardley Flood has gradually evolved since flood management structures on the River Chet were decommissioned following the 1953 floods. Its value to wetland birds is now recognised, alongside other international sites, by its designation. Cetti’s Warbler first bred in the UK in the 1970’s with the population expanding in recent decades as winters have become milder - see the map opposite for example of locations where you can find Cetti’s Warblers (Point 1). Little Egret, Spoonbill (Point 2 in the map) and Great White Egret (Point 3 in the map) have successfully bred in Norfolk, benefitting from climate and wetland environments. Some invertebrates have colonised from the near continent and further afield, including many species of moth and dragonfly. For example, breeding colonies of Willow Emerald damselfly (see Point 4) and Lesser Emperor (see Point 5) now breed in the plan area, with the latter being able to tolerate brackish conditions. However, similar opportunities can also be taken by invasive non-native species, which need to be appropriately managed.

Some mobile species could adapt to the changing climate by relocating, either within the local area, or further afield. This requires sufficient, suitable habitat which can support the populations at ‘steeping stone’ locations. This is particularly important for invertebrates, who are less mobile than birds.

For some species already low in numbers and requiring specific habitats, there is a high risk of extinction in the BFI area, if the habitats are susceptible to climate change. For example, some species depend on good quality freshwater habitat which does not regularly flood with saline and/or nutrient rich water. The iconic Swallowtail butterfly is mobile, but can only range around 30 miles from the Broads, where no suitable milk parsley habitat exists. The milk parsley is itself rare. Extinction of this unique British subspecies would represent a significant biodiversity and cultural loss. The BFI Plan could consider flood risk management opportunities that help create new, more sustainable habitats for species, particularly those with a stronghold in the Broads.

Our overall health and wellbeing is linked to us being comfortable with our climate, as this helps us to build the communities, economy and the lifestyle that we desire.

Warmer weather could encourage us to spend more time outside, and the renowned landscapes of the coast and Broads support a thriving recreation and tourism industry. Therefore, whilst we must avoid the harmful effects of heatwaves and sun damage to skin, there are recreational and tourism opportunities across the area which the BFI recognises and could support. Buildings can be adapted to provide greater cooling, including through shading, building orientation and different materials, rather than air conditioning which would mean greater demand for energy. These measures could be considered alongside methods used to construct flood resilient buildings, which could incorporate nature-based solutions (e.g. green roofs) where possible.

A serious impact of increased flooding is the heightened risk of injury and threat to life. Whilst the plan area is relatively flat, fast flowing water remains dangerous and even shallow flowing water can knock a person over, or move a car. The trauma and stress people experience during flooding leads to high levels of anxiety and distress. Following a flood, buildings are damp and susceptible to mould, with these being associated with up to a 50% increase in breathing related problems. Resilience can be improved through preparation, e.g. signing up for flood alert systems and having an evacuation plan.

Although the climate of south-eastern England could change to be like that of northern Spain, it does not mean regular calm, sunny conditions. Extreme weather could occur more frequently and our infrastructure and behaviors must adapt appropriately. For example, footpaths near to water and along embankments may be at risk of closure during and after flooding, higher water levels could more regularly limit boat navigation as clearance under bridges reduces, increased aquatic plant growth may require greater management, and changing water conditions may lead to different fish species being present, affecting angling.

Climate change could have both positive and negative influences on our health and wellbeing. The BFI plan could promote climate resilient infrastructure, and nature-based solutions in particular, to help build climate resilient places which benefit our health and wellbeing.

Natural flood management techniques include reducing soil compaction for better infiltration, less runoff and erosion; woody debris dams upstream in a watercourse to slow the flow of water and encourage infiltration and uptake by vegetation; and storing water in wetlands and other natural features. These approaches provide wildlife habitat, store carbon and improve the overall value of the environment. For examples of where these techniques were applied, see the map opposite.

Peat helps mitigate climate change through storing carbon. Restoring damaged peat allows these benefits to continue. Wetland habitats which can form peat are a prominent feature of the plan area. The Fingringhoe and Wallasea schemes in Essex are man-made wetlands which also store carbon. These schemes in Essex have been collaborations between partners and landowners, responding to the coastal squeeze of the nearby coast and creating new habitat for birds and other wildlife, in addition to improved flood management. 

Sustainable Drainage Systems (SuDS) is the term given to natural flood management techniques which are applicable in urbanised areas. Planted areas for water to pond, green roofs for buildings, paved surfaces which are permeable and water butts are some of the techniques used to mimic natural processes, storing and making water available for reuse, and decreasing the flow of water from urban areas to rivers and the sea. 

Flood storage areas are opportunities for collaboration across many sectors to manage flooding and improve availability of good quality water. This was successfully achieved at Halvergate marshes- click on the map to know more.

Buildings can be adapted to climate change including by making them more resilient to flooding (e.g. fitting flood doors, using flood-resilient materials). Traditional Broadland buildings by the riverside are often timber framed and able to be periodically raised on supports as the soft ground below settles. Click on the map for further examples.

Norfolk and Suffolk are recognised for leading the transition to an economy where carbon emitted to the atmosphere is balanced with that captured and stored from it. It is the only place in the UK where all forms of energy resources and generation exist together, including being at the heart of the world’s largest market for offshore wind energy. This shift to a ‘net zero’ economy is already changing our behaviour, for example as a population, we are reducing our power use and considering buying electric cars. Similarly, the UK government’s commitment to ‘net zero’ emissions by 2050, and cascading commitments from BFI partners (including the Environment Agency), will influence how flood risk management is delivered. For example, the carbon impact of new schemes is already considered alongside cost, environmental benefits and other factors when deciding between options for flood risk management.