The intensity of the late Holocene drought in northern China related to Arctic Sea ice

Abstract

Understanding the evolution and mechanisms of past droughts can provide critical insights for drought prediction in northern China in the context of global warming. During the late Holocene, drought was frequently in northern China; however, its spatial patterns and intensities have received less attention. Here, we present a high-resolution moisture record based on alkenone proxies from Daihai Lake (Inner Mongolia, China), which indicates a long-term decline in water depth in spring during the late Holocene. Notably, significant reductions in water depth were observed during the periods of ca. 4.3–3.4 cal ka BP, 2.5–2.2 cal ka BP, 1.5–0.8 cal ka BP, and the current warm period. In conjunction with published reconstructed precipitation records for northern China, we found that widespread and severe droughts occurred at ca. 4.3–3.4 cal ka BP, and 1.5–0.8 cal ka BP due to decreased monsoon rainfall, which closely corresponds to the expansion of Arctic sea ice and the weakening of Atlantic Meridional Overturning Circulation. Additionally, the most widespread and severe drought occurred at the period 1.5 to 0.8 cal ka BP in northern China, possibly linked with the expansion of sea ice in the North Atlantic. Importantly, the intensity of droughts resulting from the weakened summer monsoon circulation in northern China increases with latitude. In the current warm period, the spring water depth of Daihai Lake has reached its lowest level since the late Holocene, likely due to the enhanced evaporation resulting from climate warming. These findings suggest that, under the influence of ongoing global warming, spring drought, along with lake shrinkage and salinization in northern China, may intensify.