Extended Data Fig. 4: Temperature reconstructions from eastern African lakes used to rescale the ca 75-kyr MST record from Lake Chala, and from other reference sites.
From: Reversed Holocene temperature–moisture relationship in the Horn of Africa
a, Lake-based temperature reconstructions from eastern African lakes (sites 1–7 in Fig. 1a): Garba Guracha102, Sacred95, Rutundu30, Mahoma103 (all derived from branched GDGTs), Victoria104, Tanganyika105 and Malawi106 (from the TEX86 index based on the distribution of isoprenoidal GDGTs; Extended Data Table 1). b, Ensemble regional temperature reconstruction for eastern Africa during the last 25 kyr, calculated by averaging normalized temperature trends from the seven reconstructions shown in a. The blue and red frames cover 3000-year intervals of the cold early late-glacial period (21-18 kyr ago; average temperature anomaly −2.8 °C) and warm mid-Holocene (7-4 kyr ago; average temperature anomaly +2.0 °C) which together encompass a total amplitude of 4.8 °C regional temperature change across the glacial-Holocene transition. c, Lake Chala MST time series for the last 45 kyr, estimated using BSR of branched GDGT distributions in a global lakes calibration dataset19 and rescaled to match the amplitude of the regional ensemble reconstruction (Methods). Purple shading shows the +2 °C RMSE envelope of this calibration, similarly rescaled to +0.7 °C. Data from samples partly consisting of thin turbidites are indicated as grey crosses and excluded from interpretation. d, Sea surface temperature (SST) anomaly record for the equatorial western Indian Ocean (site 8 in Fig. 1a) based on the magnesium to calcium (Mg/Ca) ratio of planktonic foraminifera in deep-ocean sediments off northern Tanzania (grey line) with 400-year rolling mean (black line)126. e, Alkenone-based SST record for the Mozambique Channel127 (site 9 in Fig. 1a). f, Regional temperature reconstruction for southeastern Africa based on fossil pollen assemblages128 (site 10 in Fig. 1a). The timing of the Younger Dryas (YD), Heinrich-1 stadial (HS1), the Last Glacial Maximum (LGM) and marine isotope stages 1–3 (MIS1-MIS3) are indicated for reference. Considering linear age interpolation in the >25.2-kyr section of the proxy time series shown in c (Methods), the timing of Heinrich events H2–H4 is approximative only (as indicated by gradated light grey shading).
