Greening cities and green architecture are increasingly recognised as vital strategies for addressing climate change driven by carbon pollution. Benefits also extend beyond carbon reduction to include shade and shelter, visual amenity, and the promotion of biodiversity.

In the greening of cities, Singapore has emerged as a global leader, implementing innovative development controls that could be readily adapted to Australian cities.

Singaporean architecture firm WOHA has long championed these initiatives, proposing green plot ratios, topographic architecture, sky parks and sky gardens in their 2016 publication Green City Mega City: Rethinking Cities for the Age of Global Warming. While Singapore’s Urban Redevelopment Authority (URA) – the agency responsible for land use planning and development – has progressively introduced a comprehensive suite of incentives, including:

– Landscape Replacement Area (LRA): Requiring developments in designated city areas to replace up to 100% of their total site area with accessible green space.

– Landscaping for Urban Spaces and High-Rises (LUSH): Supporting vertical greenery and green roofs, along with rooftop urban farming, to optimise underutilised rooftops.

– Green Plot Ratios (GnPR): Ensuring sufficient greenery density, measured by total leaf area as a ratio of site area, akin to how floor area is used in plot ratio controls.

These initiatives represent groundbreaking steps in sustainability and follow from WOHA’s notable 2013 ParkRoyal Pickering hotel, which doubled the greenery of its site area.

Lush landscaping is now the standard on Singapore’s major developments. By 2017, two-thirds of new residential developments and half of new offices, shopping centres, and hotels had adopted LUSH incentives for GFA bonuses.

Change is also underway in Australia. For example, Brisbane City Council has trialled a Green Building Incentive Scheme supporting deep planting, green walls, facades, and green roofs. Meanwhile, the City of Melbourne has developed a strategic action plan for vertical and rooftop greening, along with a tree valuation tool that calculates the cost to developers for removing public trees – under this formula, the amenity value of a 90-year-old elm can exceed $200,000.

Above: Sky park and green wall, Guoco Midtown | DCM + DP Architects | Image: Finbarr Fallon.

I became fully acquainted with the URA’s greening policies while working on the design of Guoco Midtown, a mixed-use development near Raffles Hotel. The project achieved 94% LRA, in addition to complying with the URA’s code for Privately Owned Public Spaces (POPS).

POPS is another initiative contributing to the quality of the public realm and urban life within cities. In Australia, where we have adopted dense, high-rise city centres, the provision of open space is essential.

POPS dates to a 1961 New York City zoning regulation enabling developers to gain floor area bonuses in exchange for publicly accessible open spaces, typically plazas or arcades. Early iterations, however, often resulted in windswept, underused plazas, prompting an early rethinking of the code.

Around this time, urbanist William H. Whyte conducted pioneering research into human behaviour in urban settings. His landmark 1979 book, The Social Life of Small Urban Spaces, identified factors that made some plazas successful and others not. This led to an upgraded POPS code requiring seating, landscaping, weather protection, activation, lighting, safety and accessibility contributions – essential ingredients for high-amenity spaces. Developers embraced the concept, and today New York City has over 590 designated POPS.

In 2007 we designed a very large commercial complex, Asia Square in Singapore, with a 6,000 m² roofed public space, or City Room. Having lived in Singapore, running our office in the 90s, I was acutely aware of the combination of equatorial sun, heat and frequent torrential downpours, making it imperative to cover open space to be truly useable.

Above: The 6,000 m² City Room at Asia Square created a POPS precedent in Singapore in 2014 | DCM + A61 | Image: John Gollings.

As a student, I recall being struck by an image Leon Krier produced on a lithograph of a piazza in Rome where he overlaid a vast high-pitched roof on four gigantic stone legs above the urban fabric, calling it ‘a living room for the city’, or what we now designate City Rooms. They have helped define great cities, with Milano’s Galleria being one of the most famous. I always wanted to do something like this. At Asia Square we created a 17-metre-high City Room, naturally lit and ventilated, overlooked by a food garden and activated by restaurants, bars, and lobbies. The building owners regularly organise events, making it a key neighbourhood space in the Financial District. Upon completion the URA were impressed, looked at New York POPS, and enacted their own guidelines and controls.

Since then, numerous POPS with a green focus have been completed, such as Ingenhoven Architect’s Marina Bay, with a covered tropical garden containing 160,000 plants from 350 species, and Foster and Partner’s wave-like glass canopy sheltering six different gardens at South Beach.

Above: Wave-like sheltering POPS at South Beach | Foster + Partners | Image Adrian FitzGerald.

For Guoco Midtown, the LRA required an extraordinary 22,200 m², more than double the open space at Asia Square. Additionally, 25% of the ground floor footprint had to be POPS, with 50% shaded space, movable public seating at a specified ratio, and connection to continuous weather-protected pedestrian links.

Achieving LRA requires a multi-layered, volumetric approach. Guoco Midtown has eight plazas and gardens, including two City Rooms, sky parks and terraces across six levels. Each space has a unique character; for example, Midtown Market accommodates outdoor dining, weekend markets, and events under a glazed steel-framed roof with hanging planters.

Above: Green replacement was achieved over 6 levels at Guoco Midtown | DCM + DP Architect | Image DCM.

The GFA bonus incentivised the developer, GuocoLand, to provide these urban amenities along with workplace health and wellbeing facilities in the sky park, including a running track, 50-metre pool, and bookable garden spaces coupled with two POPS, each with a different character.

Above: Guoco Midtown Square activated, sheltered naturally ventilated POPS | DCM + DP Architect | Image Finbarr Fallon.

Drawing from Singapore’s experience, I strongly advocate for green and POPS incentives in Australian planning schemes. These, coupled with innovative measures promoting green architecture, will help promote sustainable lifestyles in vibrant, green cities.

Main image: An early innovator, ParkRoyal on Pickering with multiple levels of greenery | WOHA | Image Patrick Bingham-Hall.

By Adrian FitzGerald, Senior Director at Denton Corker Marshall (DCM).

Architecture & Design Team

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