How circularity levers influence material flows

Narrow, slow, and close act on different parts of the system

Circularity levers are applied sequentially in these scenarios through actions that narrow, slow, and close material loops. The core principles underlying the circularity levers are drawn from the Four Flows Framework.¹⁷³ This has, however, been adapted for the model used in this analysis. For more details on how these are applied in the model, refer to Chapter two.

• Narrowing flows—Use less: reducing material intensity through efficiency improvements and product design, for example.

• Slowing flows—Use longer: extending material lifetimes through repair, reuse, refurbishment, and remanufacturing.

• Closing material loops—Use again: increasing collection and recycling performance to recover materials for secondary supply.

Circularity levers are applied cumulatively—material efficiency first (narrow), then lifetime extension and product recovery (slow), then end-of-life recovery (close)—so their individual contributions should be interpreted in the context of their corresponding value chain stages.

In a supply-constrained system, reducing demand first closes the gap between desired demand and realised supply. Only once that gap has been closed does further demand reduction translate into lower primary extraction. Because narrow is applied first, much of its effect is spent reducing unmet demand rather than reducing extraction. Across materials and pathways, it cuts unmet demand by roughly 10% to 55% while producing relatively little change in primary supply. Slow, which is applied second, operates after the service gap has already narrowed, so its impact more often appears as avoided primary extraction. The two levers therefore make complementary contributions: narrow primarily improves the balance between demand and available supply, while slow reduces the amount of material required to maintain that balance. See Chart 45 for more insights.

Close behaves differently because its effectiveness depends on the availability, maturity, and performance of end-of-life recovery systems. Under a high decarbonisation pathway, close becomes the largest single contributor to reducing primary supply for cobalt, overtaking slow, because rapid growth in battery production generates a substantial scrap pool early enough for improved recovery to capture it. By contrast, copper and nickel already operate with collection systems close to their practical ceiling, so further improvements in recovery make a comparatively smaller contribution to reducing primary supply.

The relative contribution of each circularity lever—narrow, slow, and close—depends both on where the material is constrained in the system and on when the relevant material becomes available for reuse. Narrow acts primarily on demand, slow changes the timing and volume of replacement flows, and close becomes increasingly powerful once sufficient end-of-life material accumulates. The value of each lever is consequently conditional on the state of the wider material system rather than being fixed across materials or decarbonisation pathways.