Document Type

Article

Publication Date

1-27-2026

Department

Department of Biological Sciences

Abstract

Land cover data are commonly used to model the terrestrial carbon (C) sink, yet these data have wide margins of error that significantly alter estimates of global C storage. Here we demonstrate this data vulnerability in grasslands, which are critical to C cycling but whose estimated distribution has varied by >50 million km (3.5-42% of the Earth's terrestrial surface). Comparing multiple high-resolution land cover products with expertly annotated grassland data from six continents, we show sources of mapping error and discuss C implications based on 2023 United Nations (UN) FAO estimates. Past misidentification arose from inconsistent definitions on grassland identity and classification flaws especially relating to woody plant cover. Correcting these errors adjusted grassland coverage to 22.8% of the terrestrial land base (30.1 million km), elevating UN projections of soil C stocks to 155.02 Pg (0-30 cm depth). These findings underscore the challenges of biome mapping for ecosystem accounting and policy, when lacking field-validated remotely sensed data.

Publisher's Statement

© The Author(s) 2026, modified publication 2026. Publisher’s version of record: https://doi.org/10.1038/s41559-025-02955-6

Publication Title

Nature ecology & evolution

Creative Commons License

Creative Commons Attribution 4.0 International License
This work is licensed under a Creative Commons Attribution 4.0 International License.

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Publisher's PDF

Included in

Biology Commons

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