Temperature effects on carbon storage are controlled by soil stabilisation capacities

Iain P Hartley,Gustaf Hugelius,Sarah E Chadburn,Tim C Hill

doi:10.1038/s41467-021-27101-1

Iain P Hartley, Gustaf Hugelius + Show 2 more

Open Access

https://doi.org/10.1038/s41467-021-27101-1

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Abstract

Physical and chemical stabilisation mechanisms are now known to play a critical role in controlling carbon (C) storage in mineral soils, leading to suggestions that climate warming-induced C losses may be lower than previously predicted. By analysing > 9,000 soil profiles, here we show that, overall, C storage declines strongly with mean annual temperature. However, the reduction in C storage with temperature was more than three times greater in coarse-textured soils, with limited capacities for stabilising organic matter, than in fine-textured soils with greater stabilisation capacities. This pattern was observed independently in cool and warm regions, and after accounting for potentially confounding factors (plant productivity, precipitation, aridity, cation exchange capacity, and pH). The results could not, however, be represented by an established Earth system model (ESM). We conclude that warming will promote substantial soil C losses, but ESMs may not be predicting these losses accurately or which stocks are most vulnerable.

Highlights

Physical and chemical stabilisation mechanisms are known to play a critical role in controlling carbon (C) storage in mineral soils, leading to suggestions that climate warminginduced C losses may be lower than previously predicted
By analysing the soil profile data[17], we investigated whether the effect of temperature on soil C storage varies with stabilisation capacities, as indicated by soil textural properties
A value of 1 indicates no change in C storage with temperature, values less than 1 indicate C stocks increase with temperature and values greater than 1 indicate C stocks decline with temperature, with, for example, a value of 2 indicating that C stocks halve for every 10 oC increase in temperature

Summary

Introduction

Physical and chemical stabilisation mechanisms are known to play a critical role in controlling carbon (C) storage in mineral soils, leading to suggestions that climate warminginduced C losses may be lower than previously predicted. By analysing the soil profile data[17], we investigated whether the effect of temperature on soil C storage varies with stabilisation capacities, as indicated by soil textural properties.

Results

Conclusion