65 Hydroclimate Variability Across Timescales in Western North America: Causes and Consequences (Posters)

This session aims to bring together researchers studying past climate change over a range of timescales using innovative data and modeling approaches and using these data to inform future changes in climate and their impacts.

Sunday, 19 October 2025
8:00 AM - 5:30 PM
HBGCC, Hall 1

Spatial Signatures of Temperature and Precipitation Changes in the Western US During the Younger Dryas

Paper number: 65-3
Program: Technical Sessions
Time: 8:45 AM – 9:00 AM

Authors

Abstract

The Younger Dryas (YD, ~12.9–11.7 ka) was marked by pronounced cooling (>5 °C) in the high-latitude North Atlantic, commonly attributed to an AMOC slowdown triggered by North Atlantic meltwater discharge. Its expression beyond the North Atlantic was widespread but spatially heterogeneous. In the western United States, precipitation responses vary across basins and proxies, and quantitative temperature constraints remain sparse. We generate new brGDGT-based temperature and dDwax  reconstructions from Southwest U.S. sites and integrate them with a regional synthesis of hydroclimate-sensitive proxies; comparison with climate model simulations constrains the magnitude, spatial heterogeneity, and seasonality of Younger Dryas hydroclimate changes. The brGDGT reconstructions indicate modest mean-annual cooling of ~1.0–2.0 °C across most sites, while the isotopic and hydroclimate responses lack a uniform YD signature, implying regionally variable precipitation pathways and/or seasonally compensating changes. Proxy–model comparisons help reconcile divergent western U.S. proxy signals and to diagnose mechanisms linking AMOC perturbations to North Pacific circulation and western U.S. hydroclimate.

Geological Society of America Abstracts with Programs. Vol. 57, No. 6

doi: 10.1130/abs/2025AM-414711

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