Global dry-wet patterns under various driving factors and their applications in projecting the future

Abstract

From the paleoclimate perspective, investigating driving factors and dynamics mechanisms in different cold and warm periods can provide a scientific analogy for projecting future dry-wet patterns under global warming. Here, we conduct a systematic assessment of typical cold and warm periods, including the Last Glacial Maximum (LGM), Mid-Holocene (MH), Pre-industrial (PI), Younger Dryas (YD), Bølling-Allerød (B/A), Little Ice Age (LIA), and Medieval Warm Period (MWP), with the comprehensive analysis of modern observations, climate simulations, and paleoclimate records to investigate the combined effect of various driving factors will have on the future global dry-wet patterns. Across the globe, various driving factors represented by ice sheets, orbital forcing, greenhouse gases, Atlantic Meridional Overturning Circulation (AMOC), and solar activity in different cold and warm periods have different impacts and sensitivities to regional dry-wet patterns. Based on the paleoclimate results of dry-wet patterns in typical cold and warm periods, future weakening AMOC will cause northeastern Europe, southeastern East Asia, and northern and southeastern South America to be drier, while if greenhouse gases continue to rise and the ice sheets continue to melt, this will lead to increased drought in the Mediterranean, southern North America and the southwest coast of South America.