Misty view of Millennium bridge & the Shard

Overheating & sunlight – challenges for central London planners

In Southwark Council we are currently developing the planning policy framework for the Old Kent Road Opportunity Area, which involves planning for 20,000 new homes and 5,000 additional jobs in the area. We are committed to delivering high quality, healthy, low carbon communities and are interested in learning from the latest research, so when I heard about the ARCC/CIBSE event on overcoming obstacles to high density cities, I was keen to participate.

The event did not disappoint. The presentations were excellent and varied, and we had some great discussions on our table between the talks. Having a modeller, a university researcher, engineers and a planner (me) around the one table proved a great combination, and I think we all enjoyed talking through the issues and thinking about the gaps in knowledge that need to be addressed.

I found the presentations from Prof Sue Grimmond on urban climate and heat island modelling particularly interesting. High-density development can exacerbate summer temperatures which are already rising as our climate warms. This can have direct negative impacts on comfort, health and wellbeing and can also have knock-on impacts on active cooling demand in buildings, further exacerbating the urban heat island (UHI). Prof Grimmond’s presentation demonstrated that UHI modelling has developed much further than I had realised; for example, see the UMEP tool online. This could open up opportunities for the Greater London Authority to research and develop policies requiring high density schemes in central London to model their impact on the UHI (taking into account building geometry, albedo, vegetation, shadowing, anthropogenic heat sources, etc.), and demonstrate how their impact would be mitigated e.g. through significant street tree planting or retrofit of green roofs.

Lee Chapman’s presentation on big data and advances in the availability of cheap, internet connected heat sensors was also thought provoking. Given increasing concerns about overheating in buildings as peak summer temperatures rise with climate change, particularly in dense urban areas, it made me think that the availability of these sensors could open up new opportunities for research collaborations between policymakers, developers and academia to cost effectively collect better data on summer indoor temperatures for different types of homes. Such data will be extremely valuable for improving the robustness of thermal modelling sometimes used for assessing planning applications.

Lastly, I would highlight Dr Paul Littlefair’s presentation and in particular his emphasis on the health and wellbeing benefits of daylight and sunlight. This seems to reinforce the argument made by Chris Twinn and others that performance standards for sunlight and daylight should be introduced into policy, since the widely used BRE approach on site layout planning is for guidance only. Perhaps such policies could also consider setting differential standards for certain types of area / development. For example, higher sunlight and daylight standards may be justified for public spaces in high-density urban areas where they will be important amenity spaces for large numbers of people year round.

I look forward to more of these valuable opportunities to bring together researchers, practitioners and policymakers working on urban environmental issues in future.

This blog represents the personal views of the author.

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