Late-glacial to late-Holocene shifts in global precipitation δ 18 O

• Published in: Climate of the Past
• Main Authors: S. Jasechko, A. Lechler, F. S. R. Pausata, P. J. Fawcett, T. Gleeson, D. I. Cendón, J. Galewsky, A. N. LeGrande, C. Risi, Z. D. Sharp, J. M. Welker, M. Werner, K. Yoshimura
• Format: Article in Journal/Newspaper
• Language: English
• Published: Copernicus Publications 2015
• Subjects: Environmental pollution; TD172-193.5; Environmental protection; TD169-171.8; Environmental sciences; GE1-350; ice core
• Online Access: https://doi.org/10.5194/cp-11-1375-2015; https://doaj.org/article/071425b6a18643bda5c1aded8bb2bec5

Reconstructions of Quaternary climate are often based on the isotopic content of paleo-precipitation preserved in proxy records. While many paleo-precipitation isotope records are available, few studies have synthesized these dispersed records to explore spatial patterns of late-glacial precipitation δ 18 O. Here we present a synthesis of 86 globally distributed groundwater ( n = 59), cave calcite ( n = 15) and ice core ( n = 12) isotope records spanning the late-glacial (defined as ~ 50 000 to ~ 20 000 years ago) to the late-Holocene (within the past ~ 5000 years). We show that precipitation δ 18 O changes from the late-glacial to the late-Holocene range from −7.1 ‰ (δ 18 O late-Holocene > δ 18 O late-glacial ) to +1.7 ‰ (δ 18 O late-glacial > δ 18 O late-Holocene ), with the majority (77 %) of records having lower late-glacial δ 18 O than late-Holocene δ 18 O values. High-magnitude, negative precipitation δ 18 O shifts are common at high latitudes, high altitudes and continental interiors (δ 18 O late-Holocene > δ 18 O late-glacial by more than 3 ‰). Conversely, low-magnitude, positive precipitation δ 18 O shifts are concentrated along tropical and subtropical coasts (δ 18 O late-glacial > δ 18 O late-Holocene by less than 2 ‰). Broad, global patterns of late-glacial to late-Holocene precipitation δ 18 O shifts suggest that stronger-than-modern isotopic distillation of air masses prevailed during the late-glacial, likely impacted by larger global temperature differences between the tropics and the poles. Further, to test how well general circulation models reproduce global precipitation δ 18 O shifts, we compiled simulated precipitation δ 18 O shifts from five isotope-enabled general circulation models simulated under recent and last glacial maximum climate states. Climate simulations generally show better inter-model and model-measurement agreement in temperate regions than in the tropics, highlighting a need for further research to better understand how inter-model spread in convective rainout, ...