Fig. 3: Using spatial variability of soil carbon turnover time to estimate ΔC_s,τ.

a Scatter-plot of the relationship between \(\mathrm{log}\,{\tau }_{{\rm{s}}}\) and mean air temperature from observations^19,20,21,24 (black points), and a quadratic fit (black-dotted line) representing the observational temperature sensitivity of \(\mathrm{log}\,{\tau }_{{\rm{s}}}\). The equivalent quadratic fits for the ESMs are shown by the coloured lines; b The proof of principle for our method, showing an actual vs. estimated comparison, representing the modelled versus the relationship-derived values of the ΔC_s,τ, where the change is considered between the start (1995–2005) and the end (2090–2100) of 21st century and is assumed to relate to the top 1 metre of soil.