Tomer Fishman

Floods threaten lives and infrastructure, while recovery and reconstruction require materials whose production generates greenhouse gas emissions. These material needs and emissions remain insufficiently quantified. Here we assess the impacts of riverine and coastal flooding on building materials across Europe under climate change and land subsidence. Baseline annual replacement demand is about 30 million tonnes of materials, generating about 9 million tonnes of carbon dioxide equivalent emissions. With flood protection maintained but not upgraded, both could increase more than tenfold by 2080 under a moderate emissions scenario, driven by coastal flooding. Impacts could be about 22% higher under a high emissions scenario. Cumulative replacement emissions over 2024–2080 under the moderate scenario could reach 4.0 billion tonnes of carbon dioxide equivalent, exceeding ten times Europe’s annual building material production emissions in 2020. Increasing both mitigation and adaptation efforts is essential to reduce material losses, further emissions and human suffering.

Transportation infrastructure stocks are a large share of global material stock, comprising around 30%–50% of global material stock. As emerging economies expand and developed nations have growing maintenance needs, increasing material demand presents a critical barrier to decarbonising the built environment. Using a stock-driven material flow analysis model based on infrastructure stock data from 8872 urban areas and rural regions, under an SSP2 scenario for transport demand, we identify a population shift toward urban areas leading to increased resource requirements in urban areas, and an increase of total infrastructure stocks to 494 Gt between 2024 and 2070. While urban areas demonstrate a density advantage, depopulating rural areas face an increasing material inefficiency. Material demand related to transport infrastructure expansion is concentrated in the Global South, whereas Global North materials are mainly used for maintenance and increasing stocks of underutilised assets in rural areas. A spatial challenge exists of providing the resources in the right place.

The circular economy (CE) is a promising strategy to decouple the Japanese residential sector from resource depletion and climate change. We provide a high-resolution analysis of CE potentials in the sector at the prefectural level. In addition, we develop an integrated framework to model the turnover of buildings by including new construction, demolition, and renovation targets, and include a scenario that accounts for inequalities in the provision of floorspace service. Our results suggest that CE strategies alone save ~14% (Base_CEs) while 31% can be expected when CE strategies are coupled with a more compact living space (LEMD_CEs). The cumulative 2020-2050 savings in GHG emissions are expected to reach 22%, with values ranging from 12% (Okinawa) to 31% (Toyama) at the prefectural level. We estimate that vacant stock will rise from 0.3 billion m2 in 2015 to 1.1 billion m2 in 2050, mostly due to low demolition rates.

The Belt and Road Initiative (BRI), the world’s largest ongoing infrastructure endeavor, tackles urgent development needs in underserved regions. However, its construction phase, especially material extraction and processing, may have far-reaching climate implications that remain poorly known. Here, we present the first global, project-level assessment of greenhouse gas (GHG) emissions embodied in the construction of over 700 individual BRI projects (2008–2024) across 105 countries. By integrating a detailed project data set with a physically grounded global supply chain model that captures material-specific sourcing patterns, we estimate 134 Mt of CO₂ equiv emissions, around half of which occur outside the project host countries. This reveals the previously unquantified global supply chain reach of the BRI. Depending on operational performance, BRI renewable energy projects may achieve emission reductions comparable in scale to the construction-phase emissions within 2 years. Our results underscore the need and opportunity to embed cleaner material sourcing and sustainability assessment into BRI and other transnational infrastructure efforts.