Mismanaged Plastic Waste (Lebreton et al. 2019)

Source: Lebreton et al. (2019) Year: 2015 Category: Transition risks · Pollution · Plastics Coverage: Global Format: Raster grid (~1 km) Used in risk analysis: Yes — gates Pollution

What it shows

This layer maps where mismanaged plastic waste is generated — plastic that is littered, dumped or inadequately disposed of and so is liable to leak into the environment. Concentrations of mismanaged plastic waste matter for nature-related risk because they indicate priority areas for pollution pressure on rivers, coasts and oceans, and pinpoint where mitigation policies would have most effect.

How it is built

The layer is based on Lebreton et al. (2019). The authors combined country-level waste-management data with high-resolution distributions and long-term projections of population and gross domestic product to estimate where mismanaged plastic waste is produced. The result is a global surface of plastic-waste generation at roughly 1 km resolution, with projections extending to 2060. The study estimated 60–99 million tonnes of mismanaged plastic waste produced globally in 2015, potentially tripling by 2060 under a business-as-usual path, and found that most of this waste (around 91%) is transported via larger watersheds — underlining rivers as major pathways to the ocean.

How to read it

Higher values indicate more mismanaged plastic waste generated at a location and therefore greater plastic-pollution pressure; lower values indicate less. The mapped load is disproportionately high across parts of Africa and Asia and is projected to remain so without substantial investment in waste-management infrastructure.

Class thresholds

The underlying layer models a physical flux: mismanaged plastic waste generation, in kilograms per km² per year (kg/km²/year) — the mass of plastic that is littered, dumped or inadequately disposed of (and so liable to leak into the environment) generated per unit area per year. The five risk classes map to the following thresholds on that quantity:

A site is flagged on the Pollution dimension when the layer value exceeds 200 kg/km²/year (i.e. it reaches the High-Risk class or above).

How these thresholds were set. This is a Darwin in-house classification: an order-of-magnitude (log₁₀) binning of the Lebreton et al. (2019) generation surface, each class one decade above the previous. No external entity publishes class breaks for this quantity, so Darwin applies a decadal log scale to span the very wide value range (from near zero to thousands of kg/km²/year). The breaks are not derived from WWF or any other published standard.

Source

Lebreton, L., Andrady, A., & Boucher, J. (2019). Global patterns of mismanaged plastic waste. Science Advances / Palgrave Communications. Resolution ~1 km, projections to 2060.

Comparison with the WWF Risk Filter Suite

This layer contributes to the WWF Biodiversity Risk Filter pollution theme (BRF S13_4 Pollution), specifically the plastics dimension. WWF references the Lebreton river-plastic work alongside Eriksen ocean-plastic data; Darwin uses the Lebreton mismanaged-waste generation surface directly. It is aligned with the same source family WWF draws on for plastic pollution.

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: Plastic

Generated from darwin/layers/layer-mismanaged-plastic-waste-lebreton-et-al-2019.toml and risk_indicator_pairs.toml (develop).