Drying in the Middle East During Northern Hemisphere Cold Events of the Early Glacial Period

Few paleoclimate records exist to assess the central Middle East's response to natural forcing beyond the instrumental record. Here, we present a multiproxy stalagmite‐based climate reconstruction from Iran's semiarid northeast that spans 100–70,000 years before present. During severe cold (stadial) events in the North Atlantic at ≈88, 77, and 73 ka, stalagmite trace‐element data indicate anomalously dry periods at this location. Stadial event increases in the stalagmite oxygen isotopes mirror those in a published Iranian stalagmite 800 km to the west. A global climate model simulates drying across the Middle East region in response to stadial event forcing, in agreement with oxygen isotope enrichments in both Iranian records, caused by a smaller fractional loss of moisture on the trajectory upstream. The paleoproxies and model experiments are consistent in indicating a drier Middle East climate during the cold North Atlantic stadials. Iran is particularly vulnerable to the effects of climate change due to its scarce water availability. Iran's climate likely changed in the past due to natural causes, indications of which can be found in climate archives such as tens‐of‐thousands‐of‐year‐old cave stalagmites. Stalagmites record evidence of changes in rainfall pattern and amount. This study presents a reconstruction of both regional and local rainfall changes based on the geochemistry of stalagmites from northwest and northeast Iran. The record covers 100–70,000 years before present, a period when ice sheets covered North America and northern Europe, and Earth was experiencing multiple abrupt shifts to even colder conditions in the Northern Hemisphere. Each event's shift to colder temperatures lasted for a few thousand years. We show that both the stalagmite geochemical data and state‐of‐the‐climate models are consistent in indicating a drier Middle East climate during these cold events. Trace‐element data in a northeastern Iran stalagmite suggest anomalously dry local conditions during Greenland stadial events 22–20Climate model results and changing Iranian oxygen‐isotope gradients show evidence of a drier Middle East during these stadials