Circular construction policies key to reversing nature loss in cities, says new IUCN report

The report, Circular construction policies for nature: Regenerative approaches for the built environment through city action, finds that the built environment's most damaging impacts on nature occur not within cities, but far beyond them — in the quarries, forests and steel mills that supply construction materials. As a result, policies that curb material demand have a greater positive effect on ecosystems than measures focused solely on local green space.

The construction sector consumes more than 40% of the world's raw materials, says the report. Residential and commercial development affects up to 28,996 species, nearly half of which face extinction risk. Mining and quarrying for construction materials threaten a further 14,000 species. Together, these two drivers account for a third of all species at risk of extinction globally, according to the IUCN Red List of Threatened Species™.

The report examines circular economy policies in four European cities — Brussels, London, Paris and Zurich — and finds that while all four have made meaningful progress, there is still significant untapped potential to benefit nature.

Among the findings: demolition moratoriums and renovation support schemes — policies that extend building lifespans and reduce the need for new raw material extraction — deliver the greatest immediate nature benefits. Mandating the use of recycled and secondary materials in new construction also ranks high and forces the sector to innovate while reducing upstream extraction pressures.

For example, since 2005, Zurich’s public procurement has required a minimum amount of recycled concrete in all public building projects. By 2019, that policy had saved some 17,000 cubic metres of raw materials and reduced landfill use. 

In Paris, the city has shifted its focus towards densification and retrofit with urban planning prioritising renovation over new build and encouraging adaptive reuse and energy-efficient upgrades. As part of a multi-faceted approach, a referendum passed last year also calls for greening 500 streets. 

The report's authors urge cities to extend their thinking beyond municipal boundaries. "Circular economy discourses should go beyond decarbonisation and focus also on nature and biodiversity conservation throughout the supply chain," said Loredana Scuto, a senior programme officer with IUCN Cities, Culture and Youth Team, who launched the report last month with Holcim and ARUP at the Urban Future conference in Ljubljana, Slovenia.  

Other recommendations include embedding material reuse criteria into public procurement and land allocation, introducing circular economy requirements into construction permitting processes, prioritising policy action on high-impact materials — particularly cement, concrete and steel — and building monitoring systems that track nature-related indicators, such as avoided extraction and reuse rates. The report also underscores the need for stronger global metrics to quantify biodiversity impacts along construction supply chains—particularly for high-impact materials such as cement, steel and timber—building a clear agenda for future city, industry and policy collaboration.

"As the world’s population grows and urbanizes, the future of construction is circular and must centre on reusing, recycling, upcycling and reducing the materials used. Closing the loop in construction is critical to minimise the use of virgin resources and safeguard the natural world. For the construction sector, it is both a challenge and an opportunity for sustainable innovation," said Renata Pollini, Head of Sustainable Construction & Nature, at Holcim.

The report, produced with ARUP, is one in a series planned under a three-year IUCN-Holcim collaborative agreement.  The IUCN-Holcim partnership is focused on greening the built environment through circular economy strategies and the promotion of building-scale nature interventions as well as on biodiversity protection and water stewardship in Holcim operations and value chain. 

The full report is available via the IUCN Library here. 

For more information, visit the IUCN Urban Alliance - Index - IUCN Urban Alliance