Wild Ruminants as a Natural Source of Methane: A Global Gridded Emissions Estimate

Abstract

Methane (CH ₄ ) is a potent greenhouse gas whose global budget remains uncertain due to incomplete and uncertain constraints on several natural and anthropogenic sources. While livestock dominate animal‐derived methane emissions, emissions from wild animals—particularly ruminants—represent a persistent but under‐quantified component of the global methane cycle. In this study, we present a global, spatially explicit gridded estimate of methane emissions from wild ruminants. The data set provides yearly estimated of methane emissions for the 2000–2024 timeframe. We derive gridded methane emissions by combining species‐level population and global distribution inventories with body‐mass‐based emission estimates through an allometric relationship, allowing for a consistent representation of wild ruminant methane emissions at the global scale. Our results indicate that global methane emissions from wild ruminants sum up to around 2.95 Tg yr ⁻¹ , which is substantially lower than estimates derived from IPCC Tier 1 (∼15 Tg yr ⁻¹ ) methodologies but overlaps with previous allometric‐based assessments. Differences among estimates are primarily attributable to contrasting population data sets and methodological approaches. Although subject to uncertainties related to population data, seasonal variability, and the exclusion of non‐ruminant herbivores, this study provides a transparent and reproducible baseline estimate of methane emissions from wild animals. The resulting gridded product is intended to support global methane budgeting efforts, atmospheric modeling, and future studies aiming to refine estimates of natural methane sources.