Water stress shock (SSP3-7.0)

Source: WRI Aqueduct 4.0 (future projection) Year: 2050 Category: Scenario Coverage: Global Format: Raster grid Used in risk analysis: No (contextual layer; not used in materiality scoring)

What it shows

This layer shows how much water stress is projected to change under a high-emissions "regional rivalry" future (the SSP3-7.0 pathway). Rather than showing the level of water stress, it shows the shock — the relative shift away from today's conditions — to highlight where water availability could deteriorate (or improve) most sharply under this high-emissions scenario.

Note on the scenario. This is the pessimistic pathway used across Darwin's stress test. It is SSP3-7.0 (Aqueduct's "business-as-usual" projection), which replaced the previous SSP5-8.5 layer — the IPCC AR6 treats SSP5-8.5 as physically implausible, so SSP3-7.0 is now the high-end reference.

How it is built

Values represent the projected relative change in water stress, expressed as a percentage difference from the present-day baseline, under the SSP3-7.0 scenario. The result is presented as a grid covering the globe. Because it is a scenario shock, the layer is best read alongside the present-day water-stress layer, which provides the starting conditions the shock is applied to.

How to read it

Values capture the direction and size of change relative to baseline: larger positive values indicate areas where water stress is projected to worsen most under this high-emissions pathway, while values pointing the other way indicate easing pressure. As a scenario projection it indicates relative change, not an exact future level.

Class thresholds

The underlying quantity is a physical flux expressed as a relative change: the projected percentage change in water availability / water stress under the SSP3-7.0 pathway, relative to a present-day baseline (% change). It is symbolised on the Water availability shock (%) field.

This layer is not split into discrete risk classes. It is rendered as a continuous (symlog) diverging gradient over its native unit, the shock percentage, spanning the asymmetric range −100 % to +500 %:

The layer is contextual and is not used in materiality scoring, so it carries no five-class risk table. It does, however, define a single trigger: a location is marked as a High water-stress shock zone when the projected change passes the 30 % degradation threshold (shock value below −30 %), which feeds the Enabling/Supporting Services dimension.

How these thresholds were set. This is a Darwin in-house classification: the shock percentage is computed by Darwin's own scenario pipeline (CMIP6-driven water-stress shocks relative to a present-day baseline), and the −100 / 0 / +500 % gradient anchors and the −30 % High-shock trigger are fixed round-number cutoffs chosen in-house. They are not derived from WRI Aqueduct, WWF or any other published standard.

Source

Forward-looking water-stress shock under the SSP3-7.0 scenario. (Derived scenario layer; underlying provenance not separately attributed.)

Comparison with the WWF Risk Filter Suite

The WWF Risk Filter Suite publishes present-day indicators only. This forward-looking scenario shock has no distinct WWF equivalent; it is a scenario variant of the water-stress risk WWF covers for the present day, expressing change rather than absolute level.

Legend

Symbolised field: Water availability shock (%)

Generated from darwin/layers/layer-water-stress-shock-ssp5.toml and risk_indicator_pairs.toml (develop).