Table 1 Interventions used in the scenario analysis (for a full specification of each strategy, please see Supplementary Notes)

Intensive Use (IU, Reduce in 3R)

Reducing stocks per unit volume. For example, reducing per capita housing area, reducing road and railway density, etc.

Per capita saturated residential space is projected to decrease. For example, Beijing will drop from a baseline of 50.2 to 40.1 m².

Lightweight Design (LD, Reduce in 3R)

Reducing the material intensity of final uses. By using hollow concrete components, material substitution, optimizing building structures, etc., to reduce the amount of aggregate used per unit of functional use (per m²).

The material intensity of residential buildings is projected to decrease. For example, Beijing will see a reduction from 1.64 to 1.48 t/m² by 2050.

Lifetime Extension (LE, Reuse in 3R)

Extending the service life. Considering the improvement in the quality of buildings and major infrastructure projects, the expected service life will also increase in the future. This study extends the expected lifespan by 30% to 90% in the model, depending on the year and final use category.

Lifetime expectations of residential buildings increase. For example, Beijing sees increases from 35 years to 67 years by 2050.

Improved Recycling (IR, Recycle in 3R)

Improving the recycling rate of CDW. We match the final uses of various subcategories for recycling by setting feasible recycling rates for each type of final use.

For example, the recycling rate of demolition wastes from highways is projected to increase from 40% to 80% by 2050 across provinces.

All Measures (AM)

Apply all measures above simultaneously.