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De-carbonisation, as the science suggests should
be happening as a matter of urgency, is not
apparent. Indeed, one study found that the rate of
growth in carbon dioxide emissions between 2000
and 2007 was four times that experienced during
the 1990s. 9 As a result of this situation, research by
Anderson and Bows 10 suggests that even ‘an
optimistic interpretation of the current framing of
climate change’ leads to a scenario associated with
GHG concentrations equating to around a 3.5°C
global mean temperature rise by the end of this
century. Stafford Smith et al. 11 concur with this
analysis, noting that ‘With weakening prospects of
prompt mitigation, it is increasingly likely that the
world will experience 4°C and more of global
warming.’
We are left with a situation where climate change
impacts are being experienced more quickly and
intensely than predicted, the thresholds for
significant impacts relative to temperature increases
are being revised downwards, the non-linear
complexity of the climate system is increasingly
being acknowledged, and projections for future
changes in the climate are being ratcheted upwards
as a consequence of a lack of action by policymakers
and resulting rapid carbonisation. These
‘The severe heatwave of 2003
may have resulted in 35,000
excess deaths in Europe,
especially among the
elderly, but this extreme
event is not untypical of
conditions projected by
climate change models for
later in the 21st century’
factors encapsulate the adaptation imperative. The
discussion now turns to the consideration of
adaptation planning and response development,
with a focus on the built environment – and with
particular reference to the role of green and blue
infrastructure as a means of moderating risks
associated with a changing climate.
Climate change impacts in the built environment
A key step in developing an adaptation response
in policy and practice is to understand the likely
interaction between climate change and the system
in question. In broad terms, the IPCC has
concluded 12 that Europe is most sensitive to:
● extreme seasons, in particular exceptionally hot
and dry summers and mild winters;
● short-duration events such as wind-storms and
heavy rains; and
● slow, long-term changes in climate which will put
particular pressures on coastal areas, for example
sea level rise.
The impacts from these changes will be keenly
felt in the built environment, for it is here that
people and property are most concentrated. For
example, the climate change impacts identified as
of primary interest by the GRaBS partners, listed by
frequency of response, were high temperature (10),
flood risk (8), water resources and quality (5),
ground conditions (3), and fire risk (1).
It needs to be emphasised that natural processes
such as energy exchange and the water cycle
continue to operate in the urban environment, but
here they are modified and in some respects
amplified. In particular, the extent of vegetation
cover is reduced by urbanisation, and with it the
potential for evaporative cooling from plant surfaces.
Conversely, the built environment has a high
thermal capacity so that heat conductance and
storage increases. These and other factors, such as
multiple reflectance within street canyons,
contribute to a pronounced urban heat island,
especially at night, when temperatures may be
significantly higher than in the surrounding
countryside. In addition to energy input from solar
radiation, heat input from human sources (transport,
buildings and even human metabolism) also
contributes to the heat island effect, especially in
winter. Climate change strengthens the urban heat
island and increases the risk of heat stress among
vulnerable populations. The severe heatwave of
2003 may have resulted in 35,000 excess deaths in
Europe, especially among the elderly, but this
extreme event is not untypical of conditions
projected by climate change models for later in the
21st century. 13
Another consequence of urbanisation is surface
sealing, which reduces infiltration of rain water and
increases surface run-off. As the climate warms,
more evaporation occurs from the oceans and wet
surfaces, and the atmosphere is able to hold more
of that water – around 7% for each 1°C centigrade
rise in global temperature. One consequence is
greater rainfall intensity, which may already be
contributing to increased surface water flooding in
Europe. Urbanisation interacts with climate change
to increase this risk. For example, modelling work in
Greater Manchester suggests that a high-intensity
rainfall event which may bring 56% more rainfall in
the 2080s will result in 82% more run-off (from the
current urban form). 14
These and other potential climate change impacts
in the urban environment – such as the risk of
riverine flooding, tidal inundation, problems of
ground stability and water shortage – are beginning
254 Town & Country Planning June 2011 : GRaBS Project – INTERREG IVC; ERDF-funded