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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
Building adaptive capacity Review existing plans and policies Control development in high-risk areas Climateconscious urban regeneration Climateconscious new development Screening risks at the conurbation scale Mitigate climate change drivers Modify urban form and function Influence general behaviour Hazard Urban system Elements at risk Reduce exposure Exposure Reduce risk Vulnerability Reduce vulnerability Risk Above Fig. 1 Pathways to climate change adaptation Source: ‘The role of spatial risk assessment in the context of planning for adaptation in UK urban areas’ 16 to be well documented and understood. 12,15 There is also a growing realisation that the indirect effects of climate change may be even more significant for Europe, especially forced migration of human populations from regions severely impacted by climate change to more favourable environments. The question is, how best to prepare and respond? Pathways to climate change adaptation Fig. 1 provides a helpful, schematic framework for illustrating pathways to climate change adaptation in the urban environment. 16 Here the risk to people, property and other assets (sometimes referred to as ‘receptors’) is considered to be a function of climate-related hazard, the likelihood of exposure to that hazard, and the vulnerability of the receptors concerned. The vulnerability term, as interpreted within GRaBS, refers to inherent vulnerability of receptors within the urban system. In the case of people this is ‘social vulnerability’, which can be characterised and mapped independently of risk of exposure to the climate-related hazard. It is this approach which informed the development of the GRaBS Assessment Tool. 17 In developing adaptation strategies and formulating action plans we need to recognise that we can build adaptive capacity by reducing the likelihood of exposure to a climaterelated hazard and/or by reducing the sensitivity of vulnerable people and assets (for example buildings and critical infrastructure) should exposure to the hazard be realised: these two approaches are complementary. This approach has distinct advantages but differs somewhat from the ‘hazards and impacts’ approach of the IPCC. 18 It is clear from Fig. 1 that the form of the urban system is critically important in determining the potential for exposure to climate-related impacts. The same may be true of ‘vulnerability’, because all too often key parts of the emergency response system are sited in exposed locations. Climate Adaptation by Design, the TCPA guidance document on climate adaptation, 19 emphasises the need for an approach which takes in three interconnected levels Town & Country Planning June 2011 : GRaBS Project – INTERREG IVC; ERDF-funded 255
Page 1 and 2: The Journal of the Town and Country
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