Shifting winter atmospheric teleconnections to the North Pacific reconcile Younger-Dryas and Holocene δ18O signals

TL;DR

Ancient lake sediments show that winter climate shifts in the North Pacific were driven by different atmospheric patterns during the Younger-Dryas and Holocene periods.

Contribution

The study identifies distinct atmospheric teleconnections driving similar δ18O changes during different climate periods.

Findings

Abrupt δ18O decreases during the Younger-Dryas correlate with Greenland ice-core records and reflect winter cooling.

Late Holocene δ18O decreases are linked to sub-tropical Pacific moisture transport, not winter cooling.

Seasonality and atmospheric patterns play major roles in global climate oscillations.

Abstract

Using Alaskan lake sediment oxygen isotope records (δ18O), which trace the δ18O of precipitation, we establish that abrupt atmospheric shifts occurred during the last deglacial period in the North Pacific-Arctic. The robust lake δ18O chronologies confidently correlate Younger-Dryas (YD) atmospheric adjustments in Alaska with Greenland ice-core records and their seasonal sensitivity are consistent with cooling during winter. In contrast, abrupt δ18O decreases during the late Holocene observed in our records, of similar magnitude as the YD, are best explained by atmospheric modes involving long-distance transport of sub-tropical Pacific moisture. Our sediment cores are among the most reliably dated records yet produced in the circum-Arctic and show that similar decreases in δ18O of winter precipitation during the YD and late Holocene were driven by different atmospheric teleconnections. These results underscore major roles for seasonality and atmospheric patterns in the conceptual understanding of global scale climate oscillations, both past and future.

Ancient lake sediments reveal drivers of winter shifts in North Pacific weather patterns and seasonality’s role in abrupt climate change, which are different from summertime.

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