Fig. 1. Comparison of coral Sr/Ca-SST record with instrumental and reconstructed SST records.

(A) ERSSTv5 average annual SST. The edge of the WPWP is indicated by the annual mean SST 28°C contour (yellow). (B) Annually averaged Sr/Ca-SSTs for coral core F14 from Fiji (red) compared to SSTs from ERSSTv5 (black) (r = 0.39, P < 0.001; 1883 to 1997). (C) Spatial correlation for the SWCP (purple rectangles) with the ERSSTv5 mean annual data. The green rectangles represent the zonal gradient of the SST between the western and eastern equatorial Pacific (57). (D) Annually averaged Sr/Ca-SSTs for coral core F14 from Fiji (red) compared to the Fiji composite coral record from records 1F and AB (23) (green) over their common period of 1781 to 1997. (E) Annual Fiji composite coral record (red) combining the records shown in (D) compared to the Ocean2K SST anomaly reconstruction for the western Pacific (24) (blue) and the SST from the PHYDA close to Fiji (17°S, 117°E) (21) (green). Also shown is the most recent SST data for Fiji from ERSSTv5 (1998 to 2021) shown in (E) (black). SST presented as anomalies relative to the period of 1883 to 1996. It should be noted that records 1F and AB (23) from Fiji are also included in the PHYDA and O2KWP reconstructions. Triangles in (D) and (E) denote the timing of major volcanic events (<−3.5 W/m² values) (Fig. 2) (22) typically associated with a cooling response. Extended warm (cold) periods highlighted in (D) and (E) by red (blue) bars based on the change point analysis for the Fiji composite shown in (E) are indicated by dark red vertical lines; dark red horizontal lines indicate the mean for each period.