Tomorrow's climate will be different from today's. By the 2080s a number of changes will be evident:
- It will be warmer all year round with most of the warming in summer and autumn
- Winters will be wetter and summers drier
- It will be sunnier in summer, because of a reduction in average cloud cover and this, together with higher temperatures, will cause a large increase in summer evaporation
- It will be windier with an increased risk of severe storms
There will be an increased risk of extreme weather events. Without adaptation there could be water shortages every summer and more damage from flooding almost every winter. We will need to adapt to prevent new extremes becoming catastrophies.
New guidance was issued by Defra in October 2006. This guidance highlighted that new flood defences must be fully adaptable to the consequences of climate change and rising sea levels. It advises those responsible for building flood defences to plan for the long term, by factoring in increasing rates of sea level rise - a result of the climate change already locked in to the global system. Sea level rise is likely to accelerate; the previous 6mm/yr has been replaced in the Esatern Yar River and Coastal Strategy's study area by revised variable allowance over time (4.0mm/yr to 2025, 8.5mm/yr between 2025 and 2055, 12.0mm/yr between 2055 and 2085, and 15.0mm/yr beyond 2085).
These new allowances are shown in the table below:
Regional net sea level rise allowances
| Administrative or Devolved Region |
Assumed Vertical Land Movement (mm/yr) |
Net Sea-Level Rise (mm/yr) |
Previous Allowances |
1990-2025 |
2025-2055 |
2055-2085 |
2085- 2115 |
East of England, East Midlands, London, SE England
(south of Flamborough Head)
|
-0.8 |
4.0 |
8.5 |
12.0 |
15.0 |
6mm/yr*
constant |
South West and Wales |
-0.5 |
3.5 |
8.0 |
11.5 |
14.5 |
5mm/yr*
constant |
NW England, NE England, Scotland
(north of Flamborough Head)
|
+0.8 |
2.5 |
7.0 |
10.0 |
13.0 |
4mm/yr*
constant |
*Updated figures now reflect an exponential curve, and replaces the previous straight line graph representations.
Source: Defra (2006) Supplementary Note to Operating Authorities – Climate Change Impacts
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Defra have drawn attention to a number of key points to consider with regards to the new allowances;
- Net sea level rise allowances incorporate thermal expansion of the oceans and melt from land glaciers and vertical adjustments of the land. Additional contributions from tidal surge and waves are not included.
- Global mean sea level rise projections up to the 2080s were taken from the Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report (TAR) High estimates. Global mean sea level rise projections for the 2110s were extrapolated from the 2020s, 2050s and 2080s.
- Regional variations in net sea level rise allowances reflect latest information on vertical land movements.
- The baseline for calculating sea level rise for a given year is taken from 1990.
- There are significant uncertainties in climate change predictions and there may be studies that suggest allowances could be higher. However, figures in the new guidance are considered most appropriate for flood and coastal risk management and planning, and should be used until further updates are provided.
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