London - NbS for a leading sustainable city

The Greater London Authority (GLA) participants in the BRIDGE FP7  project identified the primary planning goals for the Central Activities Zone (CAZ)[1] as to: (a) increase green space; (b) improve air quality; (c) reduce the UHI effect (heat island) and (d) prevent flash floods, with climate change adaptation and mitigation seen as a cross cutting issue.

London has a number of plans aimed at addressing these challenges, including:

• The Mayor’s London Plan in which two goals relate to urban green space and aim at addressing vegetation loss, overheating and flooding. To address the former it was envisioned to plant 2 million trees and to increase green space by 5 % by 2030 and another 5 % by 2050 (2011a), with the street tree programme especially targeting areas known to experience overheating. It also has a Living Roofs and Walls scheme focused on creating green roofs and recreational living roofs and green walls to help London adapt to the risks of climate change such as flooding, overheating, drought; and reducing the urban heat island effect in the city (GLA, 2008). The London Plan also has some measurable objectives, including a no net loss of designated Sites of Importance for Nature Conservation over the plan period, a reduction in CO2 emissions to 23 % below 1990 levels by 2016, no net loss of functional flood plain and the production of 945 GWh of energy from renewable sources by 2010 including at least six large wind turbines.
• The London Infrastructure Plan 2050 sees green infrastructure (GI) as important in its own right and seeks to develop a business case for it (Mayor of London, 2015). The GLA has set up a Green Infrastructure Task Force to work on a more strategic and long-term approach to investing in and delivering green infrastructure.
• The Mayor’s plan for an All London Green Grid (ALGG) sought to achieve a network of high quality, well-designed and multifunctional green and open spaces and to promote a shift from grey to green infrastructure to secure environmental, social and economic benefits (GLA, 2012). Such a grid was seen as the way to address the environmental challenges of the 21st century — most notably climate change.
• The Natural Capital Investing in a Green infrastructure for Future London (GLA, 2015) takes forward ideas for the ALGG. It has the vision that by 2050 existing parks and green spaces will become part of an integrated GI network, all regeneration areas and major new developments will include GI (e.g. green roofs and walls) that is designed, amongst other things, for climate mitigation, water regulation and health; streets will be greener and more of London’s rivers will run in more natural courses in order to manage flooding, improve water quality and enhance river ecology. It also wants all people living in London to have ready access to good quality GI and for GI decisions to be based on natural capital valuation.
• The Mayor’s Air Quality Strategy (GLA, 2010) aimed to minimise greenhouse emissions and the health effects of air pollution through increasing energy efficiency and including air quality impacts in the planning process. It aimed to encourage the development of green roofs and living walls on major new developments, recognising their benefits (and that of GI as a whole) in reducing pollutants, as well as improving energy consumption, the physical environment and helping control runoff.
• The Mayor’s Climate Change Adaptation Strategy (GLA, 2011b) identified health, environment, economy and infrastructure as key focus areas. It recognised the importance of green spaces in providing ecosystem services, such as reducing flood risk by absorbing and temporarily retaining rainfall and moderating the temperature by offsetting the urban heat island effects, as well as reducing energy demand and supporting biodiversity and recreation. It also set out a vision for a Green Grid across London. The GLA also emphasised the importance of climate adaptation measures and included the suggestion of new trees for shade and green roofs for electricity substations.
• The Mayor’s Water Strategy (GLA, 2011c) outlines how London can ensure water security and tackle water scarcity and sees GI as contributing to resilience to flooding and extreme weather events, as well as improving air quality. It includes a vision to develop at least three demonstration projects to show how urban greening measures can help to manage surface water flood risk.

[1] The CAZ covers the central London area, including the central business area and the commercial centre, with an overall area of roughly 3 300 ha and about 280 000 residents (BRIDGE Community of Practice Report 2).