Water stress shock (SSP1-2.6)
This layer shows how much water stress is projected to change under a sustainable-development future (the SSP1-2.6 pathway, characterised by lower emissions and more coor
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)
Superseded. This single-horizon (2050) scenario layer is replaced by the horizon-resolved NST V1 shock set — three horizons (2035 / 2050 / 2080) under scenarios SSP1-2.6 and SSP3-7.0. See Nature Stress Test — Shock Layers. It is kept here for reference.
What it shows
This layer shows how much water stress is projected to change under a sustainable-development future (the SSP1-2.6 pathway, characterised by lower emissions and more coordinated climate action). 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 improve or deteriorate under this scenario.
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 SSP1-2.6 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 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 SSP1-2.6 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 %:
| Gradient anchor | Water availability shock (%) | Meaning |
|---|---|---|
| Green | −100 | Strongest projected easing of water pressure |
| White | 0 | No projected change |
| Dark red | +500 | Most severe projected increase in water stress |
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 SSP1-2.6 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-ssp1.toml and risk_indicator_pairs.toml (develop).