Pollination Deficit (Chaplin-Kramer)

Source: Chaplin-Kramer et al. (2019), Science Year: 2015 Category: Physical risks · Enabling services Coverage: Global Format: Raster grid (~1 km) Used in risk analysis: Yes — gates Enabling services

What it shows

This layer maps the gap in crop production caused by insufficient pollination — the share of potential yield lost because wild pollinators are too scarce. Many crops depend on insect pollination, so a large deficit signals where farming is constrained by the loss of pollinator habitat. It is a direct measure of an enabling natural service on which agricultural output depends.

How it is built

The layer is based on the global modelling of nature's contributions to people by Chaplin-Kramer and colleagues (2019), produced through the IPBES assessment and the Natural Capital Project. The measured variable is crop yield loss attributable to a shortfall in wild pollination — conceptually, the difference between the production that pollinators could support and the production actually achievable given available pollinator habitat. The output reflects current conditions (around 2015) on a roughly 1 km global grid, refined from a coarser native resolution.

How to read it

Higher values indicate a larger pollination deficit — places where crop production is more limited by insufficient wild pollinator habitat. Lower values indicate areas where pollination is adequately supplied or where crops do not depend heavily on it.

Class thresholds

The underlying layer models a continuous quantity: the pollination deficit ("benefit gap") — the share of crop production lost because wild pollination is insufficient, from Chaplin-Kramer et al. (2019). The deficit is defined only over cropland (roughly 4 % of valid pixels); across the processed global raster the observed values run from 0 to about 914, with a mean near 3.3 in the layer's native deficit units.

Rather than discrete risk classes, the layer is symbolised on a continuous colour gradient over the display domain 0 – 100 (pale yellow at 0 → dark red at 100). Values above 100 are clamped to the top of the gradient; there is no five-class break structure in Darwin's configuration.

A site is flagged on the Enabling services dimension when the layer value exceeds 50 (the High pollination deficit proximity trigger), combined with a material Pollination ENCORE pressure (≥ 4) on the activity side.

How these thresholds were set. There is no external risk-class standard behind this layer: Chaplin-Kramer's deficit is published as a continuous benefit-gap surface, not a classed product. The 0 – 100 gradient bounds and the > 50 flag cutoff are Darwin in-house display and flagging choices — round-number cutoffs on the native deficit scale, not derived from WWF or any other published classification. The exact deficit values are read directly from the source raster; only the colour stretch and the flag threshold are set by Darwin.

Source

Chaplin-Kramer et al. (2019), Science — Global Modelling of Nature's Contributions to People; IPBES / Natural Capital Project.

Comparison with the WWF Risk Filter Suite

This layer corresponds to BRF S2_5 Pollination and is aligned in concept. The difference is one of vintage: Darwin currently uses the 2019 Chaplin-Kramer release, whereas the WWF Risk Filter Suite v3.0 draws on the 2023 Critical Natural Assets update. A refresh to the newer release is pending on the Darwin side.

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: Pollination deficit

Generated from darwin/layers/layer-pollination-deficit-chaplin-kramer.toml and risk_indicator_pairs.toml (develop).