London scoping - ukcip

Final Report
171
of effect may be expected to reduce in frequency as a result of the warmer winters expected
under the climate change scenarios for London.
According to the Association of British Insurers, their members already incur costs of nearly
£1m every day on average from subsidence. This is likely to be a growing issue as summers
become drier and warmer, causing soils to shrink. Subsidence should not be a major hazard -
the fact that it is so costly in Britain, especially England, is more to do with issues around
building foundations and building standards. A new technique using satellite data, called
Permanent Scatterer Synthetic Aperture Radar Interferometry (PS InSAR) is making it possible
to measure sub millimetre movements in buildings. This could identify the worst subsidence
areas. It could also give early warning of failure of mass structures such as bridges, flood
defences, power stations and dams.
7.5.4 Impacts Due to Wind Storms
It is becoming clear, whether or not storms will become more frequent and severe with climate
change, that storm tracks are changing. In the past, it was normal for stable cold high pressure
areas to develop over Switzerland and Germany in the winter. These ‘blocking highs’ diverted
Atlantic storm tracks over the North of Scotland or Spain where houses have been designed to
cope with them. As winters in central Europe become milder, the blocking highs are becoming
weaker or shifting to the East (Parry et al., 2000). When there are milder winters in central
Europe, more storms track across the South of England and the North of France (Dronia, 1991)
where buildings are designed and constructed to lower standards. Existing historical analogues
show that there are high costs for the insurance industry of these type of events. The October
1987 storm cost insurers £1,500m at 1987 prices for UK damage alone. Overall, including
continental European losses, the economic loss was $3,700m of which the insured loss was
$3,100m. Two further such storms in England in January and February 1990 (‘Daria’ and
‘Vivian’) caused insured losses in England of £2,400m (at 1990 prices). The overall European
economic losses were $10,050m of which insured losses (at 1990 prices) were $7,200m. Three
big storms in December 1999 (‘Anatol’, ‘Lothar’, and ‘Martin’) did not affect England
seriously, but devastated large areas of Northern and Western Europe, causing economic losses
of $12,700 m of which insured losses were $6,200 million (Munich Re, 2002).
Future extreme wind storm events are expected to be one of the most significant of the climate
change impacts for the insurance industry because of the associated claims for business
disruption, utility and transport infrastructure damage and domestic property damage.
An insurance stakeholder view is that there is a clear lesson here for adaptation strategies.
Storms in London are likely to become more severe and frequent, but as buildings in London
have been designed for relatively benign weather conditions, they are likely to be more
vulnerable to storm damage. This needs to be taken into account when revising the Building
Regulations. It will also be necessary to have more stringent control through inspections on the
quality of construction and the resilience of buildings to storms or floods.
7.5.5 Raised Reservoirs
A study was carried out of the climate change impacts on the safety of British Reservoirs, using
the UKCIP98 climate scenarios. The study concluded that under a medium-high climate change
scenario the total surcharge (i.e. rise in water level above normal retention level during a storm)
could increase by about 5% by the 2050s and that embankment dams might be more vulnerable