Mapping global peatlands thickness and carbon stock

Peatlands, occupying just 3–4% of the Earth's surface area, are remarkable for holding nearly 30% of the world's terrestrial carbon (C), securely stored in their soil. These ecosystems are incredibly diverse, found from the Arctic to the Tropics and at various elevations. They perform numerous critical functions and ecosystem services, crucial for achieving the Sustainable Development Goals.

The 2022 Global Peatland Assessment reported over 500 million hectares of peatlands worldwide, emphasising the importance of evaluating their baseline status and routinely assessing their conditions. This is vital for the conservation of these significant ecosystems. While global and national extent maps of peatlands exist, there's a notable gap in information regarding global peatland thickness and carbon stock.

This study aims to perform a preliminary evaluation of global peatland thickness and carbon stock by employing digital mapping techniques. We gathered over 5,000 data points on peatland characteristics (including thickness, carbon content, and bulk density) from existing observations and maps worldwide.  We combined these observations with spatial data from earth observations representing climate, topography, and vegetation as covariates for use in machine learning methods to explicitly estimate peatland thickness and carbon stock globally at a 1 km resolution. The outcome of this work provides a first comprehensive global quantification of peat thickness, carbon content, and stock, aiding in the global modelling of peatland status and conditions.