Chapter 6 - Teleconnection between Arctic climate and tropical Indian monsoon during the Holocene

Abstract

The Indian summer monsoon (ISM) is the backbone of the agrarian economy of south and southeast Asia. The marine and continental archives of ISM precipitation suggest significant shifts during the Holocene aligned with the Arctic climate over multiple time scales. The ISM strengthened during the Greenlandian [11.7–8.3kyr (thousand years) BP (before the Present)], showing variable but overall, decreasing precipitation during the Northgrippian (8.3–4.2kyr BP), although asynchronicity exists in paleoclimatic records owing to possible age errors and resolution, and a proxy response to the changing climate. During the Meghalayan age (4.2kyr to Recent), the Indian subcontinent witnessed a protracted dry event beginning at ~4.2kyr BP and ending at ~3.4kyr BP. Other significant events of the Meghalayan age include the Medieval Climate Anomaly (MCA) and the Current Warm Period (CWP) showing a strong ISM, interrupted by the Little Ice Age (LIA)—a cold phase with low precipitation in the Indian subcontinent. The climate change over the Arctic region and North Atlantic shows a mechanistic link with the ISM during the Holocene. The millennial-scale variability in the ISM is associated with the Heinrich and Bond events. The cooling in the Arctic Sea, ice expansion in the North Atlantic, and weakening of the Atlantic overturning meridional oscillations due to high freshwater flux and ice rafting in the North Atlantic caused weak ISM precipitation over the south and southeast Asia.