A global reconstruction of sea-surface temperatures for the Last Interglacial (129-116 kyr)

A valuable analogue for assessing Earth's sensitivity to warming is the Last Interglacial (LIG; 129-116 kyr), when global temperatures and mean sea level were higher than today. We report here a global network of LIG sea-surface temperatures (SST) obtained from various published temperature proxies (e.g. faunal/floral plankton assemblages, Mg/Ca ratios of calcareous organisms, and alkenone UK'37). Each reconstruction is averaged across the LIG (anomalies relative to 1981-2010), corrected for ocean drift and with varying seasonality (189 annual, 99 December-February, and 92 June-August). Because of local δ18O seawater changes, uncertainty in the age models of marine cores, and differences in sampling resolution and/or sedimentation rates, we do not attempt to resolve changes within the LIG. Therefore, and to avoid bias towards individual LIG SSTs based on only a single (and potentially erroneous) measurement or a single interpolated data point, we report temperatures averaged across the entire LIG. The global dataset provides a remarkably coherent pattern of higher SST increases at polar latitudes than in the tropics, with comparable estimates between different SST proxies.