Homes that Don’t Cost the Earth (HDCE) is an initiative by Arup, UCL IIPP, DML and Rising Tide exploring ways to provide affordable homes within planetary boundaries.

Housing - through its construction and operation - has a profound ecological footprint. This is not only due to embodied and operational carbon emissions, but also its impact on biodiversity, land use and resources. To ensure we fulfil our housing needs within planetary limits, we need to assess holistically the impact of housing, and connect environmental and ecological limits with practical decision-making pathways. This blog sets the scene for how we start to do that, building on pioneering work by others. We invite collaboration, challenge, and feedback below, or on [email protected].

Housing Has Far-Reaching Impact

The housing sector’s highly decentralised nature makes it difficult to influence (compared to something like the electricity grid). However, the UK government’s ambition to build 1.5 million new homes this decade and retrofit 5 million existing homes within this parliamentary term [1] presents a major opportunity for positive change. The way we build, maintain, and use our homes plays a crucial role in the transition towards reducing the country’s environmental and ecological impact, as well as social and health outcomes. While other sectors in the UK such as industry and energy are rapidly decarbonising, housing continues to lag behind, making it the UK’s second highest-emitting sector (see graph below).

Figure 1 - Climate Change Committee UK sector level emissions [2]

It is evident that the housing sector must accelerate its efforts to decarbonise. However, housing’s other impacts, such as on biodiversity and land-systems, which range from local and catchment-based (e.g. drainage area of a river), to global via supply chains, remain largely unaddressed. This is, in part, due to a gap between policy ambition and real-world outcomes. For instance, in the first year of England's Biodiversity Net Gain policy, launched in 2024 to legally mandate biodiversity creation, approximately half the expected enhancements were achieved [3]. To unlock housing’s full potential for positive impact, ambitious policy must therefore be matched by effective implementation across sectors and systems, and underpinned by a deeper investment in our capabilities to act.

Housing’s Contribution to Ecological Overshoot

Housing is a key element within the broader systemic shifts that contribute to ‘earth overshoot’. The Stockholm Resilience Centre has quantified nine planetary boundaries that define this Earth system [4]. In 2021, when Arup published “Designing for planetary boundary cities”, four of the nine Planetary Boundaries had already been crossed [5]. In the latest Planetary Health Check report, published in September 2025, data shows that seven of nine planetary boundaries have been exceeded. This means the previously relative stable climate and functionality of ecosystems on which all human systems depend are under threat of collapse.

Planetary Boundaries is a conceptual framework which defines nine planetary systems and their respective boundaries from within which humanity can safely maintain a stable and resilient Earth system. Once planetary boundaries are transgressed there is an increased risk of unexpected irreversible environmental changes.

— Doughnut for urban development: A Manual [6]

Figure 2- Planetary Boundaries by the Stockholm Resilience Centre [7]

These transgressed boundaries cover a range of often interconnected indicators. Climate change, a result of increased greenhouse gas emissions, is just one of the nine ‘boundaries’. While it is the most measured and widely discussed, focusing only on the climate – that is, decarbonisation alone – can obscure other critical areas that are equally vital to maintaining the stability and resilience of the Earth system. Examples of how each boundary relates to the housing sector are summarised in the following table. It is important for housing to reduce contributions to biodiversity loss, land-system change, freshwater use and biogeochemical flows, as well as greenhouse gas emissions.

Table 1 - Translating planetary boundaries to housing sector impacts

Embodied greenhouse gas emissions from material and construction processes related to buildings and infrastructure.

Urban sprawl increasing transport emissions and decreasing sequestration. | | Land System Change: Forest cover  | Loss of natural habitats and ecosystem services due to urban expansion.

Land-use impact due to material extraction/production for construction.

Increasing demands for bio-based materials may exert new pressures on this boundary. | | Modification of Biogeochemical Flows: Modification of Nitrogen & Phosphorus Cycles | Urban development increases runoff carrying nutrients from disturbed soils.

Wastewater systems can leak nutrients into water bodies. | | Freshwater Change: Global and regional water disturbance | High water use in material production (e.g. concrete).

Water-intensive construction processes.Poor stormwater management affecting local hydrology.

Water efficient, reuse and recycling systems incorporated into homes can reduce impact. | | Change in Biosphere Integrity: Species extinction rates and ecosystem function | New development can lead to habitat fragmentation and destruction.

Pollution and noise can disrupt ecosystems. | | Novel Entities: Introduction of synthetic substances | Use of toxic chemicals in paints, sealants, insulation, and flame retardants.

Microplastics from construction waste.

Poor waste management leading to environmental contamination. | | Stratospheric Ozone Depletion: Concentration of ozone-depleting substances | Historically linked to refrigerants in HVAC systems (e.g., CFCs, HCFCs).

Modern systems still pose risks if not properly managed or disposed.

Marginal impact through improper disposal of white goods or insulation foam. | | Increase in Atmospheric Aerosol Loading: Concentration of particulate matter. | Dust and particulate emissions from demolition and construction contribute to urban air pollution and health risks. | | Ocean Acidification: Carbonate ion concentration in oceans. | Indirect impact through atmospheric greenhouse gas emissions. |