The work was led by Jinchao Song, a research fellow at the University of Michigan’s School for Environment and Sustainability, working alongside an international team of experts from China, Denmark and the Netherlands. Corresponding author Gang Liu, chair professor at the College of Urban and Environmental Sciences at Peking University, describes the approach as a complementary, physical angle on urbanization. Rather than counting floor area or population alone, the team measured the sheer quantity of concrete, steel, brick, timber and other materials locked into the built environment, building by building, across every inhabited continent. That granularity matters, because the environmental consequences of construction are ultimately determined at the scale of individual structures and the streets they line.

Previous efforts to quantify building materials have mostly operated at national or regional scales, aggregating statistics that smooth over the enormous diversity of urban forms. The handful of studies that did drill down to the building level tended to concentrate on high-income countries, leaving much of the Global South underrepresented. That gap is particularly consequential because the greatest future population growth and urbanization are expected in lower-income nations, which could drive substantial demand for new construction materials over the coming decades. By assembling a globally consistent database at the level of individual buildings, the researchers were able to identify patterns that coarser estimates simply could not capture, from the density of building coverage to the vertical profiles of entire cityscapes.

Central to the analysis is the concept of urban form, which describes how densely buildings are packed together, how tall they rise, and how much variation exists in building heights across a city. When the team mapped these characteristics against material-use efficiency, a clear pattern emerged. Cities with a dense coverage of uniformly short buildings maximized the amount of floor space available per person while minimizing the materials required to provide it. In other words, the most material-efficient city is not necessarily the one with glittering towers, but one where low-rise construction is packed tightly together, spreading homes, workplaces and services across a compact footprint without the structural overhead of height.

The physics behind this finding is straightforward but often overlooked in planning debates. Taller buildings demand proportionally more structural material, particularly steel and reinforced concrete, to carry their loads and resist wind and seismic forces. A city of uniformly low buildings avoids much of that structural premium while still achieving density if the buildings sit shoulder to shoulder. The trade-off, however, is land. High-rise construction can accommodate more people within a city’s existing footprint, which may be desirable or even necessary where land is scarce or protected. Song cautions that builders and city planners will need to weigh the material savings of dense, low-rise forms against these competing goals of land-use optimization, and the right balance will differ from city to city.

The database also revealed stark disparities in how the world’s building mass is distributed. China alone possesses roughly a quarter of the total global building weight, and together with the United States it holds the highest total building mass of any nation. Yet when the measure shifts to a per capita basis, the leaders are the Netherlands and Norway, countries whose residents are, in a very literal sense, supported by more constructed material than almost anyone else on Earth. High-income countries, home to about 16 percent of the world’s population, account for a disproportionate 46 percent of global building material consumption, a mismatch that underscores how much room exists for efficiency gains in the wealthiest urban systems.

The optimal urban form identified by the study is also unevenly distributed. More than 40 percent of the world’s dense and uniformly low cities are found in high-income countries, suggesting that the most material-efficient patterns of development are already concentrated where construction standards and planning regimes are most mature. At the opposite end of the spectrum, low-income countries host more than 80 percent of the sparse, uniformly low cities, compared with just 5 percent in high-income countries. Sparse development is the least efficient configuration, because it spreads the same floor space across more land and more infrastructure, multiplying the roads, pipes and wires needed to connect it. The contrast hints at a fork in the road for rapidly urbanizing regions.

That fork has a deadline. Of the 20 countries projected to experience the highest building material demand between now and 2050, 19 are low- or middle-income nations. The United States is the lone exception, and it is the only high-income country projected to see its population grow over the next 25 years. The implication is that the decisive choices about urban form will largely be made in places that have historically been understudied, often with limited planning capacity and under intense pressure to build quickly. Whether those cities follow the dense, uniformly low model that the data identify as most efficient, or drift toward sprawling, material-hungry patterns, will shape global material demand and construction emissions for generations.

The stakes extend well beyond the construction site. As Song points out, how cities are planned today will determine their material demand for decades, because buildings, once erected, embody their materials for the length of their service lives. Using materials more efficiently can help cities accommodate future population growth while reducing the emissions associated with construction, since less material means less energy consumed in extraction, manufacturing and transport, and ultimately less carbon released into the atmosphere. With the built environment responsible for a substantial share of global resource use and greenhouse gas emissions, the weight of the world’s buildings is, in effect, a ledger of past carbon decisions and a preview of future ones.

Benjamin Goldstein, assistant professor at the University of Michigan’s School for Environment and Sustainability and a co-author of the study, frames the work as a blueprint rather than a conclusion. The study, he says, provides new insights into what sustainable cities of the future should look like, and the challenge now is to make it happen. Turning that insight into practice will require planners in the fast-growing cities of Africa, South Asia and beyond to adopt compact, low-rise development patterns where feasible, while engineers continue to refine lighter structural systems for the places where height is unavoidable. The research was funded by the National Natural Science Foundation of China, the Ministry of Education of China, the Independent Research Fund Denmark and RurbanClimate Danida. What the 606 million weighed buildings make clear is that the future of urban sustainability may be written not in the clouds above the skyline, but in the quiet, dense, low-rise streets where most of humanity is about to live.

Subject of Research: Global building mass estimation and material-efficient urban form for sustainable urbanization

Article Title: Weighing 600 million buildings to help construct a more efficient future

Article References: Weighing 600 million buildings to help construct a more efficient future. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: urbanization, building materials, urban form, material efficiency, satellite imagery, carbon emissions, Nature Cities, city planning, Global South, construction emissions, building mass, sustainable cities

The “Urban Genome” analogy transcends metaphor, positioning the city as a living organism composed of dynamically interacting elements that mirror the complexity found in biological genomes. Just as genes encode the information necessary for life, the Urban Genome encapsulates the essential data streams, infrastructure components, social dynamics, and environmental processes that collectively define urban functionality. This comprehensive framework recognizes that sustainability is not a static goal but an emergent property arising from the intricate interplay of these components.

Central to this novel paradigm is the recognition that urban sustainability must integrate multiple dimensions—including environmental integrity, socio-economic equity, and technological resilience—within a single coherent system. The authors argue that traditional approaches, often compartmentalized and reactive, fall short of addressing cities’ systemic challenges such as climate change resilience, resource efficiency, and social cohesion. Instead, by adopting the Urban Genome framework, planners and policymakers can adopt a systems-level perspective, enabling proactive, adaptive strategies that are tailored to each city’s unique ‘genetic code.’

Technically, the Urban Genome involves the aggregation and real-time analysis of vast, multi-scalar datasets collected via smart sensors, satellite imaging, IoT devices, and citizen science platforms. This data ecosystem feeds into advanced computational models that simulate urban processes—ranging from traffic flows and energy consumption patterns to air and water quality dynamics. These models are underpinned by principles borrowed from genomics and systems biology, including network theory, feedback loops, and evolutionary adaptation, which allow cities to self-optimize based on both internal conditions and external stimuli.

For example, the Urban Genome concept facilitates the development of adaptive infrastructure that responds dynamically to environmental stressors. By integrating genomic-inspired modularity, infrastructure components can be designed to function independently yet harmoniously within the larger system, improving robustness and reducing vulnerability to shocks such as extreme weather or pandemics. This modularity enables incremental upgrades instead of expensive, wholesale replacements, cutting costs and environmental impacts.

Moreover, the framework emphasizes the importance of equity at the genetic level of urban design. Just as genetic diversity fosters resilience in biological systems, social inclusivity and diversity form the keystones of urban vitality. Through data-driven participatory platforms, marginalized communities can have a voice in shaping policies that affect their neighborhoods, ensuring that the sustainability blueprint is not only technologically sophisticated but also socially just and culturally relevant.

Another intriguing facet of the Urban Genome is its capacity to predict and mitigate the unintended consequences of urban interventions. Drawing upon artificial intelligence algorithms inspired by genetic evolution, planners can iterate various scenarios computationally, refining urban policies and designs before implementation. This predictive power is instrumental in navigating trade-offs inherent in urban development, such as balancing green spaces with housing density or transportation efficiency with air quality.

The implications extend to energy systems as well, where the Urban Genome framework supports the integration of decentralized renewable energy sources into a smart grid functioning similarly to cellular energy metabolism. This biomimetic approach enhances energy efficiency and reliability, while enabling rapid adaptation to consumption fluctuations and generation variability—a hallmark challenge in sustainable urban energy management.

Water management, a critical sustainability concern, is also reimagined within the Urban Genome. By conceptualizing water flows and retention mechanisms as part of an urban circulatory system, cities can deploy innovative green infrastructure—such as bioswales, permeable pavements, and urban wetlands—that mimic natural hydrological cycles. These interventions, embedded within the genomic framework, promote water conservation, flood mitigation, and habitat restoration simultaneously.

The authors highlight that the Urban Genome initiative represents an interdisciplinary nexus, calling for collaboration among urban planners, ecologists, data scientists, sociologists, and policymakers. This interdisciplinary integration is essential, as the complexity of urban ecosystems defies reductionist approaches. Instead, it requires a holistic synthesis of knowledge domains to grasp emergent phenomena and engineer effective solutions that are both sustainable and resilient.

Crucially, this paradigm shift necessitates a transformation in governance structures. The Urban Genome underscores the importance of adaptive governance models that are transparent, agile, and capable of integrating continuous feedback from urban residents and environmental sensors alike. The traditional top-down bureaucratic systems often impede rapid, evidence-based decision-making crucial for real-time urban adaptation.

From a technological standpoint, the use of blockchain and decentralized ledgers is suggested to enhance data security, transparency, and trust within the Urban Genome framework. These technologies facilitate secure data sharing among stakeholders, fostering cooperative urban management while protecting privacy—a critical concern in the era of big urban data.

As cities worldwide grapple with mounting pressures from climate crises, population growth, and resource scarcity, the Urban Genome offers a timely philosophical and operational blueprint. By embracing the city as a living genome—a complex, evolving entity capable of learning, adaptation, and regeneration—humanity can unlock unprecedented pathways towards urban sustainability.

Importantly, the Urban Genome does not propose a one-size-fits-all recipe. Instead, it provides an adaptable scaffold that cities can customize based on their distinctive cultural, ecological, and infrastructural contexts. This flexibility ensures the concept’s global applicability, from mega-cities grappling with hyper-urbanization in Asia to emerging smart cities in Africa and Europe’s historical urban centers transitioning toward green economies.

The potential to revolutionize urban research methodologies is another exciting consequence of this framework. By fostering an integrated data-driven ecosystem, the Urban Genome cultivates opportunities for continuous learning and innovation. Urban planners can refine cities’ ‘genetic blueprints’ iteratively, learning from real-time outcomes and evolving conditions—a process analogous to gene expression and epigenetic modification in living organisms.

The authors also draw attention to the necessity of education and capacity building to actualize the Urban Genome vision. Training the next generation of urban professionals in systems thinking, computational modeling, and participatory governance is paramount to operationalizing this paradigm. Universities, think tanks, and professional bodies will need to collaborate closely on interdisciplinary curricula and practice-oriented programs.

Finally, the research underscores that while the Urban Genome framework is technologically sophisticated, its ultimate success hinges on a collective cultural shift—a reframing of humanity’s relationship with cities as living, breathing entities. Embracing this new narrative can inspire deeper stewardship and shared responsibility, crucial elements for fostering urban landscapes that are not only sustainable but thrive through the challenges of the 21st century.

Subject of Research: Sustainable urban development through the conceptual framework of the Urban Genome integrating systems biology principles with urban planning.

Article Title: Urban Genome: a new paradigm for sustainable cities.

Article References:
Luna-Rivera, J.M., Rufo, J., Rabadan, J. et al. Urban genome: a new paradigm for sustainable cities. npj Urban Sustain 5, 77 (2025). https://doi.org/10.1038/s42949-025-00265-1

Image Credits: AI Generated