Fig. 4: Past changes in precipitation regimes for peat core CEN-17.4 relative to the current climate space of tropical African, American and Asian/Oceanian peatlands.

Climate space (precipitation amount, seasonality index⁴⁸) of tropical peatland areas derived from the CHELSA dataset⁴⁹ with spatial extent derived from the PEATMAP dataset⁵⁰, plotted as bivariate kernel density estimates (KDEs; see Methods). Dark-coloured and light-coloured surfaces indicate 68% and 95% contours, respectively, from the peak density of the KDEs. Solutions for amount and seasonality of precipitation are derived from peat \({\rm{\delta }}{{\rm{D}}}_{n \mbox{-} {{\rm{C}}}_{29}}\) values at the CEN-17.4 site, for both the pre-drying period (at 5,000 cal. yr bp, dashed lines) and the end of the drying trend (at 2,000 cal. yr bp, solid lines), and are shown as inferred using the modern relationships δD_precip–precipitation amount from Bangui, Kisangani and Kinshasa (Extended Data Figs. 5 and 6). Central Congo hosts about 77% of Africa’s current tropical peatland area. The seasonality index is dimensionless. The grey shaded region marked 'No data' is outside the solution space.