Climate has a fundamental influence on landscape character. Much of the variety in the Durham landscape comes from the differences in climate between the colder wetter uplands of the west and the warmer, drier lowlands of the east. These differences affect both the natural vegetation and the way the land is managed and farmed. There is increasing evidence that the climate is changing due to a combination of natural forces and human activities, and particularly the production of 'greenhouse' gasses like carbon dioxide. Even with concerted action at a global scale it is likely that the climate will continue to change and this will bring new challenges to the landscape.
Climate Change in the North East
The potential extent of climate change in the north east has been modelled by the UK Climate Impacts Programme (UKCIP), based on projections of likely greenhouse gas emissions under different global development scenarios. Some of their findings have been published by SustaiNE in their publication And The Weather Today Is: Climate Change in the North East. The predictions for 2080 - the range varies from a best-case scenario of concerted global action to a worst-case scenario of no action - include:
- an increase in annual mean temperatures of between 1.5°c and 4.0°c
- an increase in winter mean temperatures of between 1.0°c and 3.0°c
- an increase in summer mean temperatures of between 1.5°c and 4.5°c
- an increase in winter precipitation of between 10% and 28%
- a decrease in summer precipitation of between -18% and -45%
- a decrease in winter snowfall of between 40% and 100%
- a rise in sea level of between 6cm and 66cm
- an increase in the thermal growing season of between 40 and 100 days
These changes would bring milder, wetter winters with fewer frosts and little snow, hotter, drier summers, an increase in extreme events like flooding, and increased coastal erosion. It is impossible to predict with any certainty how these changes will affect the landscape. Some of the more likely impacts are discussed below.
Changes in Habitats
The changing climate is likely to affect the flora and fauna of semi-natural habitats that are characteristic of individual landscapes. This may include the shrinking or drying of wetlands like blanket bog and lowland raised mire, ponds, seasonal watercourses and wet woodlands, and a decline in the extent of wet grasslands. Fragile habitats on the edge of their range like the relic artic-alpine heath of upper Teesdale are likely to be particularly vulnerable. There may be damage to, or changes in the species composition of, a wide range of other habitats from heathlands and grasslands to native woodlands.
We may expect to see the localised extinction of some species and the arrival of new plants and animals both native and exotic. Increased coastal erosion from rising sea levels may threaten coastal habitats like dune systems and cliff top grasslands. There may be an increase in the incidence of forest, moor and heathland fires. The ability of habitats, and the species within them, to cope with the pressures of rapid change is already compromised in some cases by their poor condition or by their fragmentation and isolation. Improving the way they are managed and restoring connectivity at a landscape scale may increase their robustness and the ability of species to move in response to changing conditions.
Changes in Agriculture
Agriculture is likely to be affected by increases in the length of the growing season and changing patterns of rainfall. This may lead to an increase in arable cultivation in the uplands and upland fringes as they become warmer, and a decrease in cultivation, or increased use of irrigation, in the lowlands as they become drier. It is also likely to lead to the introduction of new crops or crop varieties, changes in sowing and harvesting times, changes in the management of livestock and the arrival of new pests and diseases. There may be an increase in soil erosion from extremes of winter flooding and summer drought and from changing patterns of cultivation.
Conserving landscape character and local distinctiveness in the face of significant changes in agricultural land use or management is always difficult. Strategies and guidelines for the landscape must remain flexible to allow for both changing physical conditions and changes in the global economy affected by climate change that will change the markets for agricultural produce.
Flooding and Erosion
As winters get wetter, and a greater proportion of precipitation occurs in intense events, river flows could become more variable leading to increased erosion and flooding. The risk of flooding in some areas is already exacerbated by the presence of development on floodplains or the way watercourses are engineered to prevent flooding of agricultural land. The impacts of extreme events can be reduced by restoring more natural hydrological conditions to river and wetland systems, and particularly by increasing natural flood storage on flood plains and water retention in the extensive blanket bogs of the uplands. Erosion can also be reduced by restoring bank side vegetation, and particularly riverside woodland.
Vulnerable Landscape Features
Some landscape features may be vulnerable to the effects of climate change. Mature trees in particular are vulnerable to drought, and lower summer rainfall may affect hedgerow, parkland and urban trees. The combination of more frequent winter gales and waterlogged ground arising from increased rainfall may cause damage to trees and woods. Subsidence caused by drought may cause damage to the fabric of historic buildings. Veteran trees are often already subject to stress from factors like cultivation or compaction. Improving their management may make them more robust and more able to cope with extreme events
Increased summer temperatures may lead to less healthy and less 'liveable' environments and particularly in urban areas. Historically public open space in England has not been designed to provide shade or cooling as it has been in many hotter countries. The effects of warming could be offset in some degree by the provision of higher quality urban green space, and the planting and retention of street trees
Responses to Climate Change
New technologies developing in response to climate change - such as renewable energy developments from wind farms to hydroelectric schemes and energy crops - are already bringing changes to some landscapes. Other responses to climate change will range from new flood protection schemes to 'carbon trading' schemes which may provide resources for woodland expansion or peatland conservation to store carbon, or new proposals for multi-user routes to encourage walking and cycling. These will bring both new challenges and new opportunities for enhancement to the landscape.
- To encourage monitoring of the impacts of climate change on vulnerable species, habitats, landscape features and agricultural systems.
- To promote enhanced management and restoration of vulnerable habitats and landscape features to make them more robust.
- To promote habitat restoration at a landscape scale to improve the quality of ecosystems and restore connectivity.
- To support and encourage integrated approaches to water management and flood protection including river and floodplain restoration, and the restoration of blanket bog.
- To encourage the provision and high quality design of urban green space to make urban environments more 'liveable'.
- To ensure that new renewable energy development respects the character of the landscape.
- To encourage the integration of action on climate change with wider environmental, economic and social goals.
For more information on the potential effects of climate change on the region, visit the Sustaine website.