TY - JOUR
T1 - Globally resolved surface temperatures since the Last Glacial Maximum
AU - Osman, Matthew B.
AU - Tierney, Jessica E.
AU - Zhu, Jiang
AU - Tardif, Robert
AU - Hakim, Gregory J.
AU - King, Jonathan
AU - Poulsen, Christopher J.
N1 - Funding Information:
Acknowledgements We thank B. Malevich for early discussions and explorations on LGM-to-present data assimilation, and M. Fox and N. Rapp for help in compiling the proxy data. We thank P. DiNezio for providing initial and boundary condition files for the CESM simulations, and B. Markle for assistance in compiling and sharing the ice core water isotope data. This study was supported by National Science Foundation (NSF) grant numbers AGS-1602301 and AGS-1602223, and Heising-Simons Foundation grant numbers 2016-012, 2016-014 and 2016-015. The CESM project is supported primarily by the NSF. This material is based on work supported by the National Center for Atmospheric Research, which is a major facility sponsored by the NSF under Cooperative Agreement No. 1852977. Computing and data storage resources, including the Cheyenne supercomputer (https://doi.org/10.5065/D6RX99HX), were provided by the Computational and Information Systems Laboratory (CISL) at NCAR.
Publisher Copyright:
© 2021, The Author(s), under exclusive licence to Springer Nature Limited.
PY - 2021/11/11
Y1 - 2021/11/11
N2 - Climate changes across the past 24,000 years provide key insights into Earth system responses to external forcing. Climate model simulations1,2 and proxy data3–8 have independently allowed for study of this crucial interval; however, they have at times yielded disparate conclusions. Here, we leverage both types of information using paleoclimate data assimilation9,10 to produce the first proxy-constrained, full-field reanalysis of surface temperature change spanning the Last Glacial Maximum to present at 200-year resolution. We demonstrate that temperature variability across the past 24 thousand years was linked to two primary climatic mechanisms: radiative forcing from ice sheets and greenhouse gases; and a superposition of changes in the ocean overturning circulation and seasonal insolation. In contrast with previous proxy-based reconstructions6,7 our results show that global mean temperature has slightly but steadily warmed, by ~0.5 °C, since the early Holocene (around 9 thousand years ago). When compared with recent temperature changes11, our reanalysis indicates that both the rate and magnitude of modern warming are unusual relative to the changes of the past 24 thousand years.
AB - Climate changes across the past 24,000 years provide key insights into Earth system responses to external forcing. Climate model simulations1,2 and proxy data3–8 have independently allowed for study of this crucial interval; however, they have at times yielded disparate conclusions. Here, we leverage both types of information using paleoclimate data assimilation9,10 to produce the first proxy-constrained, full-field reanalysis of surface temperature change spanning the Last Glacial Maximum to present at 200-year resolution. We demonstrate that temperature variability across the past 24 thousand years was linked to two primary climatic mechanisms: radiative forcing from ice sheets and greenhouse gases; and a superposition of changes in the ocean overturning circulation and seasonal insolation. In contrast with previous proxy-based reconstructions6,7 our results show that global mean temperature has slightly but steadily warmed, by ~0.5 °C, since the early Holocene (around 9 thousand years ago). When compared with recent temperature changes11, our reanalysis indicates that both the rate and magnitude of modern warming are unusual relative to the changes of the past 24 thousand years.
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U2 - 10.1038/s41586-021-03984-4
DO - 10.1038/s41586-021-03984-4
M3 - Article
C2 - 34759364
AN - SCOPUS:85118897228
VL - 599
SP - 239
EP - 244
JO - Nature
JF - Nature
SN - 0028-0836
IS - 7884
ER -