Sea-level Change
Rising sea levels during the Holocene transgression from 15,000 to 5,000 years BP caused the Solent River valley to become drowned. Fluctuations in sea levels followed until approximately 3,000years BP. Evidence suggests a background rate of sea-level rise of approximately 1-1.5mm per annum, until the acceleration of recent decades.
The first round of Shoreline Management Plans considered the impacts of future climate change and sea level rise by applying the precautionary MAFF guidance of 6mm per annum. DEFRA have subsequently modified these sea level rise allowances, in response to research and improved predictive climate modelling, and advice from the Intergovernmental Panel on Climate Change (IPCC). The latest guidance takes into account land movement and the effects of thermo-expansion of the sea, up to the year 2115.
The new allowances are shown below.
|
Administrative Region
|
Assumed Vertical Land Movement (mm/yr)
|
Net Sea Level Rise (mm/yr)
|
Previous allowances
|
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|
1990-2025
|
2025-2055
|
2055-2085
|
2085-2115
|
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| Eastern England, East Midlands, London, South East England |
-0.8
|
4.0
|
8.5
|
12.0
|
15.0
|
6mm/yr
|
| South West and Wales |
-0.5
|
3.5
|
8.0
|
11.5
|
14.5
|
5mm/yr
|
| North West and North East England, Scotland |
+0.8
|
2.5
|
7.0
|
10.0
|
13.0
|
4mm/yr
|
| Source: DEFRA Flood and Coastal Defence Appraisal Guidance, 2006. | ||||||
