Risk and reponse

Climate Change — Adapting to The Impacts, by Communities in Northern Peripheral Regions

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Clim-ATIC will focus on the following adaptation themes
Tourism	Energy	Risk and response management	Transport

Risk and response management

The impacts of climate change on fresh water systems

A warmer climate, with its increased climate variability, will increase the risk of both floods and droughts. This is because with higher temperatures, the water-holding capacity of the atmosphere and evaporation into the atmosphere, increases, and this favours greater climate variability, with more intense precipitation in some areas and more droughts in others. To further add to the uncertainty, precipitation may increase in one season and decrease in another.

The IPCC has projected an increase in the number of days with intense precipitation across most of Europe, and the regions most prone to a rise in flood frequencies are northern and north-eastern Europe.

In addition, as temperatures rise, the likelihood of precipitation falling as rain rather than snow increases, especially in areas with temperatures near to 0°C in autumn and spring. Snowmelt is also projected to be earlier and less abundant in the melt period.

The general term 'floods' includes river floods, flash floods, urban floods and sewer floods, and can be caused by intense and/or long-lasting precipitation, snowmelt, dam break, or reduced conveyance due to ice jams or landslides. Floods depend on precipitation intensity, volume, timing, antecedent conditions of rivers and their drainage basins (e.g., presence of snow and ice, soil character, wetness, urbanisation, and existence of dikes, dams, or reservoirs). Human encroachment into flood plains and the lack of flood response plans often increases the damage potential of flood events.

The impact of climate change on a water system will depends on the system characteristics, changing pressures on the system, how the management of the system evolves, and what adaptations to climate change are implemented. Different river catchments will respond differently to changes in climate. Much depends on the catchment physiogeographical and hydrogeological characteristics and the amount of lake or groundwater storage capacity the catchment has.

Increased rainfall amounts and intensities will have the immediate consequence of increased flooding, but the knock on effects of water erosion can affect many geomorphologic processes, including slope stability, channel change, and sediment transport.

The adverse effects of climate on freshwater systems aggravate the impacts of other stresses, such as population growth, changing economic activity, land-use change, and urbanisation. More intense rainfall will lead to an increase in suspended solids (turbidity) in lakes and reservoirs due to soil fluvial erosion, and more pollutants will be introduced to the system. Higher surface water temperatures will promote algal blooms. The capacity of water and wastewater treatment plants is overloaded of during extreme rainfall. Fish spawning time and depths will be affected and such changes will have wider ecological and economic implications for many areas.

Up until the recent EU Water Framework Directive, generally low priority has been given to water management. There was, sometimes still is, a lack of coordination between agencies, tensions between national, regional and local scales, and ineffective water governance. It is true that the uncertainty over future climate change impacts constrains the ability of organisations to adapt to changes in water supply and flood risk. But it is clear that unmanaged systems are likely to be most vulnerable to climate change and adaptation responses are needed.

Adaptation potential

First, adaptation procedures need to be developed which do not rely on precise projections of changes in river discharge, groundwater, etc. Second, it is difficult to assess in a reliable way the water-related consequences of climate policies and emission pathways. There is also a scale mismatch between the large-scale climatic models and the catchment scale. Water is managed at the catchment scale and adaptation is local, while global climate models work on large spatial grids.

Water resources management clearly impacts on many other policy areas (e.g., energy projections, nature conservation). Hence there is an opportunity to align adaptation measures across different sectors.

The main structural measures to protect against floods are likely to remain reservoirs and dykes in highland and lowland areas respectively. However, other planned adaptation options are becoming more popular such as expanded floodplain areas, emergency flood reservoirs, preserved areas for flood water, and flood warning systems, especially for flash floods. It is essential that more stringent control of floodplain development are put in place, and adhered to.

The development of adaptation strategies for coastal systems has been encouraged by an increase in public and scientific awareness of the threat of climate change to coastlines. Many countries in north-west Europe have adopted the approach of developing detailed shoreline management plans that link adaptation measures with shoreline defence, accommodation and retreat strategies. We are now seeing the development of new laws and institutions for managing coastal land.

Clim-ATIC will be looking at the impacts of climate change on two river catchment areas; Glen Urquhart in Scotland, and the City of Rovaniemi and Municipality of Kittilä in Lapland Finland. Each will be carrying out an adaptation demonstration project to look at two approaches to flood risk management. Firstly in Scotland the application of sustainable flood management practices and in particular river restoration techniques, and in Finland using GIS-based flood maps for different scenarios (1/20a, 1/50a, 1/100a, 1/250a and 1/1000a) to produce flood hazard maps that will aid development decision making.

References

IPCC (Intergovernmental Panel on Climate Change ) Fourth Assessment Report (AR4) Working Group II Report "Impacts, Adaptation and Vulnerability"