London 2062: where to start? Let’s face it; it is impossible to predict how our cities might change over the next 50 years, but we can speculate about what might happen if the UK, combined with other countries globally, failed to meet carbon reduction targets. Globally we are on a trajectory to medium or high global warming, and there is no evidence to the contrary that this will change. Consequently, this means a 2-6ºC rise by 2100, and while this blog will focus on the implications of this rise on London, cities all over the world will face adaptation issues – some similar to London, others entirely different.
Let’s start with the climate change predictions. By 2080, London’s summers are expected to be as warm as the Mediterranean climate of Marseille, but without the extra sun-hours. While some consider this ‘good’ news, the reality is that our urban and built environment is not built to cope with such weather. For example, in the 2003 heat wave, the UK alone counted 2000 heat-related deaths, while Europe suffered thousands more. While a 3-4ºC increase in winter temperatures undoubtedly cuts winter fuel poverty, a similar summer temperature increase is likely to lead to summer ‘cooling’ poverty – when the elderly in particular will struggle to cope in ill-adapted homes.
Additionally, sea levels are expected to rise by as much as 900 mm, and although annual rainfall is not predicted to change, it is the distribution of rain which will become problematic, with up to a third more rain falling in winter and nearly equivalent decreases in summer. Water problems are already being witnessed in London and elsewhere in England, as evidenced by the ‘hosepipe ban’ coming into force this month.
However it is not all bad news. While the predicted weather conditions will be new to the UK, they are already a fact of life for much of the world and building precedents in Mediterranean countries could teach us how to adapt our cities to cope with increased summer temperatures. Similarly, the Netherlands is a country with more than 50% of its landmass below sea level and can teach us how to work with water, rather than against it.
While we can only speculate about how things will change and how ‘bad’ they may get, we can and should future-proof our buildings today by undertaking adaptation measures, which simultaneously support climate change mitigation efforts. Here are my simple top 5 key adaptation and mitigation measures to undertake, for both new-build as well as retrofit of housing:
1. Insulating & increasing the airtightness of buildings helps buffer against cold winters and is also effective in assisting with warmer summers.
2. Incorporate sliding or inward-opening windows, which allow external solar shading to be closed, while allowing good natural ventilation (see also 3).
3. Ensure good night-cooling and cross ventilation, while blocking unwanted summer-sun out. Thermal mass may also play a role in buffering against high summer-time temperatures as long as good, secure night cooling is provided to release built-up heat from the daytime. Failure to do so may cause overheating.
4. Increase greenery, permeable surfaces & water storage – both at micro and macro scale. These measures will help London and many other cities deal with increased risk of localised flash floods and also the Urban Heat Island (UHI) effect, which exacerbates summer overheating. Green spaces and water squares, which collect rainwater and act as an amenity for city-dwellers, can help reduce local summer temperatures by creating a ‘park cool island’ effect, with temperatures 2–3°C lower than the surroundings. The larger the green space, the greater the tempering effect, although this effect can still be felt with small spaces too.
5. Finally, provide light coloured external surfaces at micro & macro scale. Vernacular architecture in warmer countries show that light and reflective surfaces, when used on buildings and streetscapes, can keep buildings cooler and reduce surface temperatures by 10–20°C.
Of course, future-proofing means that, while certain measures can be implemented later, others need to be effected immediately. For instance, for new build, careful site planning and taking account of orientation must happen now, as would specifying a well-insulated building fabric and inward opening windows. However, solar shading could be provided later, as long as fixings are incorporated into the initial designs to make any future adaptations easy and feasible.
Whatever the future holds, we cannot afford to be complacent – especially as the measures above, and many more, can be easily incorporated into current procedures as part of good design practice. Given the required foresight and planning, we might be able to provide buildings which aid mitigation efforts – and if need be – support the future adaptation of our cities for years to come.
Sofie Pelsmakers spoke about the above at the Future of London/UCL ‘London 2062 – Housing Seminar’ Sofie is also the author of The Environmental Design Pocketbook (RIBA Publishing)