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| Figure 1: Tianjin Eco-city design blueprint |
Radical, spatially efficient architecture is championed as a solution to climate change, pollution and urban sprawl (Joss et al, 2013). I remember coming across this fascinating notion last year at TedxUCL which made me think deeply about the use of urban space to mitigate anthropogenic pressures such as climate change.
Specifically, it connects with a subcomponent of the SRM management technique: surface albedo modification (SAM); particularly in a local-scale, urban context (Figure 2). By brightening human settlements and thus enhancing reflectivity, a potential cooling effect can be achieved to counteract the ‘urban heat island’ effect (Akbari et al, 2009; Irvine et al, 2011).
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| Figure 2: Surface albedo modification of settlements - or 'white painting' |
As roofs and pavements comprise 60% of urban space, enhancing their reflectivity can increase net urban albedo by 0.1 (Irvine et al, 2011). Yet globally, urban space only makes up a mere 0.05% of the global surface (Lenton and Vaughan, 2009). It has been suggested maintenance costs, assuming a 10 year re-painting period, could total £15,000/ha (Royal Society, 2009). For the UK alone, this would cost almost £37.3 billion annually.
Many eco-cities such as Masdar City and Dongtan have turned into 'ghost' cities because they lie abandoned. Issues surrounding bureaucracy, failure of foreign architects to understand local needs and a lack of standards mean projects are vague, impractical and wasteful (Reuters, 2015).
The global patchiness of urban settlements, coupled with long-term maintenance, makes this technique costly and ineffective. Although I find sustainable architecture fascinating, I think certain elements are, simply, 'greenwash'. Projects that require radical changes to existing infrastructure are costly and prone to corruption, whilst changes that do work with infrastructure, such as SAM, are inefficient.
- As a local-scale technique, SAM does have a cooling potential by reducing the ‘urban heat island’ effect - good for sunny, hot latitudes
- From a global perspective, it does not have the potential to mitigate climate change impacts.
I like how you've linked urban geography and geoengineering! As you say, SAM within a local, urban context doesn't make much difference on a global scale but urban geography is still really important globally especially considering over half the world's population now live in urban areas! We need to make sure new cities that are being built are low-carbon and don't end up as wasteful ghost cities; we need to increase the resilience of cities in light of global warming impacts like sea-level rise; and existing cities need to become as low-carbon as possible (e.g. lots of cities in Germany are undergoing retrofitting of building facades and new houses are often built to the Passive House Standard). If more was being done to create sustainable, low-carbon cities then maybe we wouldn't have to worry as much about geoengineering and its possible risks...
ReplyDeleteHi Milena, thank you for your comment! I completely agree that urban spaces can contribute to climate change mitigation by enhancing efficiency through infrastructure design; which are so embedded in our societies. However as highlighted above, due to the complexity of the transformation required, it can also be an extremely costly & wasteful process if not undertaken efficiently. I do feel that urban spaces need to be more involved in climate change mitigation – however this needs to be in conjunction with making changes to greenhouse gas emissions from agriculture, aviation and fossil fuel burning which contribute a much larger proportion of total emissions. I fear that if more money is spent on radically transforming urban space it could potentially distract us from the larger emitters.
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