One of the first proposals for a series of developments to meet new green measures in London is a biodiverse training facility at Wimbledon, a green-walled skyscraper located in the City of London, and a densely planted mini-forest in Chelsea.
New planning metrics in Mayor Sadiq Khan’s London Plan have skyscrapers, historic estates, and suburban parks all across the capital adding up scores for greenery. These new metrics are designed to increase development’s contribution to the environment.
The Urban Greening Factor (UGF) formulaInspired by the Swedish city Malms green points system score each part of a development plan including street-level area, balconies, roofs, and roofs from 0-1. Trees, planters, and green roofs earn high scores while paving slabs, barren rooftops, receive no score. The Environment Act 2021 has also been developed by the central government to ensure that developments contribute to biodiversity. This will require a 10% net gain.
How does the green space factor work?
The green space factors (GSF), also known by urban greening or green area factor, are a method of calculating green space requirements in new developments. They give each square metre of tarmacked garage a score zero and every square square metre left as open space a value one. Other spaces may earn higher or lower scores. Malm also gives one to a stormwater system or pond that has been flooded for more then half a year. A permeable gravel area with some plants scores 0.4 and paved areas to channel stormwater to sustainable drainage systems scores 0.2. Each development may be required to meet a minimum target, which is usually 0.3.
Craig Robertson, head sustainability at AHMM architects, stated that the Urban Greening Factor is a significant step-change in how green stuff was put on buildings. Even city centres will be required to achieve a UGF score below 0.4. This is equivalent to donating 40% of their footprints to nature. Robertson stated that biodiversity net gains will represent another significant shift. This will force developers to take into account the ecological and vegetation benefits to their surroundings. It’s very difficult, but it can be done in a positive manner. It’s a great challenge.
Arc Landscape Design and Planning founder Vanessa Ross said that it is up to ecologists, developers, and ecologists to decide if the new metrics will make a real difference to London’s ecosystems and lives. Or if they will simply push architects to design by numbers. Ross explained that while private gardens may be highly regarded for green space, they can also offer little benefit to people if they are not accessible.