London scoping - ukcip

Final Report
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5.6.6 Adaptation Options
The ability of ecosystems to adapt to the direct effects of climate change is largely a function of
genetic diversity and the rate of change (IPCC, 2001b). A growing body of evidence suggests
that climate change should be treated as a current, not just a future, threat to species (Hughes,
2000; McCarty, 2001). However, humans may intervene in the processes through a range of
conservation methods. One approach to protect declining wildlife and plant populations is to
establish reserves or designated areas. Unfortunately, the Institute of Terrestrial Ecology,
estimate that 10% of all UK nature reserves could be lost within 30-40 years, and that species
distributions could change significantly in 50% of designated areas in the same period (DETR,
1999). Moreover, nearly all land suitable for designation is already protected, and some habitats
are relatively well protected compared with others (e.g., the distribution of SSSIs largely reflects
endangered plants).
A further difficulty involves reconciling the disparity between the current distribution of
reserves and future distributions of species due to climate forcing (e.g., due to coastal squeeze).
In this respect London’s ‘green corridors’, such as river corridors and railway lines, may be
important for species migration, and should be protected (EA, 2001a). Another solution may be
for planners to recognise biodiversity hotspots (Myers et al., 2000) – areas containing
concentrations of endemic species facing extraordinary threats of habitat destruction (IPCC,
2001b). Under such a scheme, a wetland threatened by summer water-level drawdown would
figure explicitly in regional water resource strategies. Such activities might fall within a wider
remit of habitat restoration (Petts and Calow, 1996). Other options include captive breeding and
translocation programmes for endangered species, but no techniques currently exist for
translocating intact biological communities (even space permitting).
Area designations and planning controls should also be considered within the wider context of
environmental improvement, recognising that fully pristine habitats are non-existent. For
example, many aquatic species are sensitive to changes in river flow and associated water
quality. Although chemical General Quality Assessment (GQA) has improved in recent years,
the biological quality of London’s rivers and of the tidal Thames continues to be variable as a
consequence of rainfall fluctuations affecting urban runoff and effluent quality (EA, 2001b). In
such circumstances, adapting to changes in climate might involve the introduction of new water
treatment technologies for more stringent quality standards (as part of the work already being
undertaken on Combined Sewer Outfalls (CSOs) under the AMP3 process). However, the
benefits of more stringent effluent treatment should be weighed against associated increases in
greenhouse gases (Colquhoun, pers. comm.), to evaluate the net environmental impact.
Treatment of diffuse pollution sources arising from agricultural areas beyond London, could be
addressed through raised awareness, and the establishment of riparian buffer zones along river
corridors (Wade, 2001). Similarly, an appreciation of the complex (transdisciplinary) processes
involved can lead to environmental enhancement in the face of change. For instance, effective
coastal defence and habitat conservation can be accomplished through soft engineering
measures that acknowledge the strong link between geomorphic and ecological processes (Lee,
2000).
5.7 Summary
The above sections provide an assessment of the most significant potential climate change
affects on London’s environment, identified through literature review, stakeholder consultation,
and impacts modelling. The key issues are summarised in Table 5.9. These themes provide the