Ecoregion shock (SSP1-2.6)
This is a forward-looking scenario layer.
Source: Darwin scenario model (ecoregion condition) Year: 2050 Category: Scenario Coverage: Global Format: Raster grid Used in risk analysis: No (contextual layer; not used in materiality scoring)
Superseded. The Habitats (Structural & Biotic Integrity) component is now backed by LUH2 % natural habitat, not this Ecoregion shock — see Natural-habitat shock (LUH2). This single-horizon (2050) layer is replaced by the horizon-resolved NST V1 set (2035 / 2050 / 2080, scenarios SSP1-2.6 and SSP3-7.0); see Nature Stress Test — Shock Layers. Kept here for reference.
What it shows
This is a forward-looking scenario layer. It estimates how the condition of each ecoregion could change under a sustainable-development future, helping anticipate where ecosystems may degrade over time rather than describing present-day conditions. It is intended as a strategic, scenario-based view of nature-related risk.
How it is built
The layer represents the projected relative change in ecoregion condition, expressed as a percentage, under the SSP1-2.6 pathway — the "sustainable development" socio-economic scenario, characterised by lower emissions and stronger environmental stewardship. Values are modelled as a change relative to a present-day baseline. Because it is a scenario projection, the figures should be read as plausible trajectories under a specific set of assumptions rather than as observations.
How to read it
Values range from roughly -71% (severe projected degradation of ecoregion condition) up to 0% (no projected change). More negative values flag ecoregions expected to deteriorate most under this scenario; values near zero indicate ecoregions expected to remain stable.
Class thresholds
The underlying layer models a continuous physical quantity: the projected relative change in ecoregion condition, in percent (%) under the SSP1-2.6 pathway — a modelled shock relative to a present-day baseline. The layer is rendered as a continuous (symlog) colour ramp over the range -75% to 0% rather than as discrete risk classes, so there is no five-class break table:
| Reading | Ecoregion condition change (%) |
|---|---|
| Stable | near 0 |
| Increasing degradation | progressively more negative |
| Most severe modelled loss | down to ≈ -71% |
A site is flagged on the Enabling-services dimension when the projected change is a degradation of more than 30% (i.e. the layer value falls below -30%).
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 ecoregion-condition shocks), and the -30% trigger is a fixed round-number cutoff chosen in-house. It is not derived from WWF or any other published standard.
Source
Darwin forward-looking scenario layer (SSP1-2.6), projected relative change in ecoregion condition. Detailed source attribution pending.
Comparison with the WWF Risk Filter Suite
The WWF Risk Filter Suite publishes present-day indicators only. This is a forward-looking scenario variant of ecosystem-condition risk, so it has no distinct equivalent in the WWF methodology. It complements WWF's static view with a scenario-based trajectory.
Legend
Symbolised field: Ecoregion shock (%)
Generated from darwin/layers/layer-ecoregion-shock-ssp1.toml and risk_indicator_pairs.toml (develop).