Arctic climate-Indian monsoon teleconnection during the last millennium revealed through geochemical proxies from an Arctic fjord

Abstract

Some of the most visible signs of climate change can be found in the northern high latitude region. Due to dynamic glacial-marine contrast, sedimentary geochemical proxies from western Svalbard fjords may provide a detailed account of paleoenvironmental changes in the region. We constructed a multivariate sedimentary record from a high-Arctic fjord (Kongsfjorden) using the sediment core NP14-FM. The new multi-proxy record includes sedimentary organic matter (OM) concentrations and their carbon and nitrogen isotopic composition, covering a period between AD 1106 and AD 1967. Using an unsupervised learning technique, the multivariate data was partitioned into two groups, helping us identify occurrences of warm and cold Arctic spells at multi-decadal resolution during the last millennium. Individually, the δ15N variability forms a highly coherent pattern with surface temperature records while δ13C and elemental OM concentrations reveal changing mixing proportions between marine and terrestrial sources. Furthermore, the region's interchanging warm and cold episodes, as detected by the multivariate sedimentary record, were linked to stronger and weaker summer monsoon over India, respectively. Modulation of meridional thermal gradients over the Indian monsoon domain amid contrasting climatic conditions in the Arctic region likely facilitated the observed Arctic-Indian monsoon teleconnection during the last millennium.