Roles of insolation forcing and CO2 forcing on Late Pleistocene seasonal sea surface temperatures

• Published in: Nature communications 2021-09, Vol.12 (1), p.5742-5742, Article 5742
• Main Authors: Lee, Kyung Eun, Clemens, Steven C., Kubota, Yoshimi, Timmermann, Axel, Holbourn, Ann, Yeh, Sang-Wook, Bae, Si Woong, Ko, Tae Wook
• Format: Article
• Language: English
• Subjects: 704/106/2738; 704/106/413; Carbon dioxide; Carbon dioxide concentration; Climate change; Climate variability; Glacial periods; Greenhouse gases; Humanities and Social Sciences; Ice sheets; Insolation; multidisciplinary; Paleoclimate; Pleistocene; Radiative forcing; Science; Science (multidisciplinary); Sea surface temperature; Seasonal variations; Summer; Surface temperature; Temperature; Temperature gradients; Winter
• ISSN: 2041-1723; 2041-1723
• DOI: 10.1038/s41467-021-26051-y

Late Pleistocene changes in insolation, greenhouse gas concentrations, and ice sheets have different spatially and seasonally modulated climatic fingerprints. By exploring the seasonality of paleoclimate proxy data, we gain deeper insight into the drivers of climate changes. Here, we investigate changes in alkenone-based annual mean and Globigerinoides ruber Mg/Ca-based summer sea surface temperatures in the East China Sea and their linkages to climate forcing over the past 400,000 years. During interglacial-glacial cycles, there are phase differences between annual mean and seasonal (summer and winter) temperatures, which relate to seasonal insolation changes. These phase differences are most evident during interglacials. During glacial terminations, temperature changes were strongly affected by CO 2 . Early temperature minima, ~20,000 years before glacial terminations, except the last glacial period, coincide with the largest temperature differences between summer and winter, and with the timing of the lowest atmospheric CO 2 concentration. These findings imply the need to consider proxy seasonality and seasonal climate variability to estimate climate sensitivity. How temperatures at different seasons differ in response to different forcings is not well known. Here, the authors reconstruct annual and seasonal sea surface temperatures in the East China Sea and show that they react differently to CO2 and insolation forcing on glacial-interglacial timescales.