Min temperature of coldest month — SSP3-7.0 2071-2100 (CHELSA)

Source: CHELSA-CMIP6 v2.1 (Karger et al.) Year: 2071-2100 Category: Physical risks · Mitigating services · Climate Chronic Risks · 2071-2100 Coverage: Global Format: Raster grid (~2 km) Used in risk analysis: No (contextual layer; not used in materiality scoring)

What it shows

This layer projects the minimum temperature of the coldest month for the end of the century (2071–2100) under a high-emissions pathway (SSP3-7.0). It indicates how winter cold extremes are expected to shift in a future of limited climate action, signalling where milder winters could alter species ranges, pest survival, growing seasons and frost-dependent ecosystem processes.

How it is built

The layer comes from the CHELSA-CMIP6 v2.1 bioclimatic dataset (Karger et al.), which downscales global climate model output to a fine grid with terrain and atmospheric corrections. This surface is a future projection for 2071–2100 under the SSP3-7.0 scenario, drawn from a single climate model (MPI-ESM1-2-HR). Relying on one model, it captures the projected direction and broad magnitude of change but not the full range of model uncertainty. It is provided globally at roughly 2 km grid spacing.

How to read it

Higher (less negative) values indicate milder projected winters under this scenario; lower values indicate colder seasonal minima. The layer is most informative when compared against the matching 1981–2010 baseline: the difference between the two reveals how much winter cold extremes are projected to change. As a single-model projection, it is best read as indicative of relative change rather than a precise local forecast.

Class thresholds

The underlying quantity is a physical variable: projected minimum air temperature of the coldest month, in degrees Celsius (°C), for 2071–2100 under the SSP3-7.0 high-emissions scenario. This is a continuous-gradient layer with no discrete risk classes — pixel values are the projected temperature itself, rendered on a smooth colour ramp spanning roughly −40 °C to +25 °C (the display range; the underlying data is not clipped to it). There is no risk-flag threshold: the layer is contextual and is not used in materiality scoring.

How these thresholds were set. There are no class breaks to set — the colour ramp is a Darwin in-house display choice (a linear stretch over the −40 °C to +25 °C range, kept identical to the 1981–2010 baseline layer so the two can be compared directly), not a classification. The temperature values themselves come unchanged from the CHELSA-CMIP6 v2.1 SSP3-7.0 projection (MPI-ESM1-2-HR).

Source

CHELSA-CMIP6 v2.1 bioclimatic layer (Karger et al.), minimum temperature of the coldest month, SSP3-7.0 projection for 2071–2100 (MPI-ESM1-2-HR). Open licence.

Comparison with the WWF Risk Filter Suite

This is a forward-looking bioclimatic scenario variant with no separate equivalent in the WWF Risk Filter Suite. WWF publishes present-day indicators; end-of-century climate projections such as this are temporal variants that WWF does not itself produce. It should be treated as a Darwin climate-context extension rather than a mapping onto a specific WWF indicator.

Legend

Symbolised field: Min temperature of coldest month

Generated from darwin/layers/layer-chelsa-tasmin_coldestmonth-ssp370.toml and risk_indicator_pairs.toml (develop).