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Climate Change: Sea Level

Volume 701: debated on Thursday 8 May 2008

asked Her Majesty's Government:

Whether the United Kingdom is facing particular problems from the rise in world sea level, especially in low-lying and heavily populated areas, as outlined in the United Nations Intergovernmental Panel on Climate Change's fourth assessment report. [HL3296]

Rising sea levels is an issue that affects many coastal areas both in the UK and around the world. The fourth assessment report (AR4) of the Intergovernmental Panel on Climate Change (IPCC) concluded that world sea levels could rise by 0.18m to 0.59m (relative to 1980 to 1999) by the end of the 21st century, as a result of global warming. These estimates do not include future changes in ice dynamics, which could increase the contribution of ice sheets to sea level rise over the 21st century. The AR4 identified low-lying islands in the Pacific and flood plain deltas like Bangladesh as particularly vulnerable regions.

For the United Kingdom, the impact of sea level rise on flooding and coastal erosion is certainly a challenge and risk for Defra and operating authorities (Environment Agency, local authorities and internal drainage boards). The potential increase in intensity, severity and frequency of coastal storms, as another consequence of climate change, also needs to be considered in this context. The risks may include an increased frequency of coastal flooding, with greater potential for coastal erosion.

asked Her Majesty's Government:

What role United Kingdom scientists are playing in the use of aerial photography to determine rises in sea level. [HL3298]

Aerial photography is a technique that UK scientists have been using to a limited extent, primarily as an indirect means of estimating sea level rise caused by ice loss from glaciers.

The British Antarctic Survey (BAS), which is funded by the Natural Environment Research Council (NERC), has a unique archive of aerial photography for Antarctica, going back to the 1940s. Scientists at BAS have made extensive use of this time-series photography to identify ice volume loss in Antarctic peninsula glaciers, which is contributing to sea level rise. Using data from both this archive and other sources of information, a collaborative study between BAS and the US Geological Survey, published in the journal Science in 2005, found that 87 per cent of the 244 glaciers studied had retreated over the last half-century. Loss of ice volume in Antarctic peninsula glaciers contributes to sea level rise.

More generally, direct measurements of sea level rise are made using satellite altimetry. Monthly and yearly mean values of sea level at all UK sites are retained by the Permanent Service for Mean Sea Level (PSMSL), which is based at the Proudman Oceanographic Laboratory. Also, Defra is working with the Environment Agency and the Proudman Oceanographic Laboratory to measure and understand the effects of vertical land movement (sinking in south-east England and rising in the north of the country), caused by melting of ice at the end of the last ice age.