Wildfire Hazard (NASA FIRMS NOAA-21)

Source: NASA FIRMS (VIIRS NOAA-21) Year: 2024-2026 Category: Physical risks · Mitigating services · Climate Acute Risks Coverage: Global Format: Raster grid (~5 km, derived from ~375 m detections) Used in risk analysis: Yes — gates Mitigating services

What it shows

This layer measures exposure to wildfire based on recent satellite observations of active fires. Wildfire threatens ecosystems and biodiversity through habitat loss and species displacement, undermines carbon storage and climate regulation, and puts settlements, agriculture and forestry at risk. The layer indicates where fire activity has been most concentrated.

How it is built

The layer is built from NASA FIRMS active-fire detections captured by the VIIRS instrument on the NOAA-21 satellite, averaged over three years (January 2024 to March 2026), following the WWF Biodiversity Risk Filter methodology. Only fires flagged with nominal or high confidence are kept. The detections are normalised by area (fires per 1,000 km²) to give an average annual fire density, which is then sorted into five risk classes. Using detections from 2024–2026 means the layer reflects very recent fire activity.

How to read it

The layer uses a five-class scale. Higher classes indicate greater wildfire exposure — areas with the highest density of detected fires — while lower classes indicate little or no recent fire activity. A site is assessed by the class of the grid area it falls within.

Class thresholds

The underlying layer models a physical flux: active-fire density — the average annual number of satellite-detected fires per 1,000 km² (fires/1000 km²/year), computed from NASA FIRMS VIIRS NOAA-21 detections (nominal/high confidence only) averaged over January 2024 – March 2026. The continuous fire density is binned into five ordinal risk classes on the following thresholds:

A site is flagged on the Mitigating services dimension when it falls in a high wildfire-hazard zone — a layer score of ≥ 4 (the High or Very-high class), i.e. a fire density of ≥ 21 fires/1000 km²/year.

How these thresholds were set. The five-class split follows the WWF Biodiversity Risk Filter (BRF) methodology applied to the NASA FIRMS fire-density data; the class boundaries (1, 4, 21, 85 fires/1000 km²/year) are consistent with the BRF's percentile-based scoring of the global fire distribution and are not a Darwin in-house rule. The exact derivation is set in the WWF BRF methodology and is not re-documented here.

Reference: WWF Biodiversity Risk Filter — riskfilter.org/biodiversity.

Source

NASA FIRMS — Fire Information for Resource Management System; VIIRS NOAA-21 active-fire detections (2024–2026, three-year average). Classification follows the WWF Biodiversity Risk Filter methodology.

Comparison with the WWF Risk Filter Suite

This layer maps to BRF S3_2 Wildfires and is aligned: WWF uses MODIS / NASA FIRMS active-fire data, the same source family. Darwin's use of recent 2024–2026 NOAA-21 detections keeps the fire signal current.

Risk analysis

A site is flagged on a dimension by combining a proximity trigger (this layer) with an activity trigger (the entity's ENCORE pressure/service). Proximity only → Potentially material; proximity and the matching ENCORE pressure/service is material → Very material; neither → Not material.

Legend

Symbolised field: Wildfire hazard level (WWF methodology)

Generated from darwin/layers/layer-wildfire-hazard-nasa-firms-noaa-21.toml and risk_indicator_pairs.toml (develop).