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McKay NP, Kaufman DS, Arcusa SH, Kolus HR, Edge DC, Erb MP, Hancock CL, Routson CC, Żarczyński M, Marshall LP, Roberts GK, Telles F. The 4.2 ka event is not remarkable in the context of Holocene climate variability. Nat Commun 2024; 15:6555. [PMID: 39095415 PMCID: PMC11297131 DOI: 10.1038/s41467-024-50886-w] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/01/2024] [Accepted: 07/22/2024] [Indexed: 08/04/2024] Open
Abstract
The "4.2 ka event" is a commonly described abrupt climate excursion that occurred about 4200 years ago. However, the extent to which this event is coherent across regional and larger scales is unclear. To objectively assess climate excursions in the Holocene we compile 1142 paleoclimate datasets that span all continents and oceans and include a wide variety of archive and proxy types. We analyze these data to determine the timing, significance and spatial imprint of climate excursions using an objective method that quantifies local, regional and global significance. Site-level excursions in temperature and hydroclimate are common throughout the Holocene, but significant global-scale excursions are rare. The most prominent excursion occurred 8200 years ago, when cold and dry conditions formed a large, significant excursion centered in the North Atlantic. We find additional significant excursions between 1600 and 1000 years ago, which agree with tree-ring data and annual-scale paleoclimate reconstructions, adding confidence and context to our findings. In contrast, although some datasets show significant climate excursions 4200 years ago, they do not occur in large, coherent spatial regions. Consequently, like most other periods in the Holocene, the "4.2 ka event" is not a globally significant climate excursion.
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Affiliation(s)
- Nicholas P McKay
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA.
| | - Darrell S Kaufman
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Stéphanie H Arcusa
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
- Arizona State University, School of Complex Adaptive Systems, Tempe, AZ, USA
| | - Hannah R Kolus
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
- Rhodium Group, Washington, DC, USA
| | - David C Edge
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Michael P Erb
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Chris L Hancock
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Cody C Routson
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Maurycy Żarczyński
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
- Department of Geomorphology and Quaternary Geology, Faculty of Oceanography and Geography, University of Gdansk, 80309, Gdansk, Poland
| | - Leah P Marshall
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Georgia K Roberts
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
| | - Frank Telles
- Northern Arizona University, School of Earth and Sustainability, Flagstaff, AZ, USA
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Lehnertz K. Time-series-analysis-based detection of critical transitions in real-world non-autonomous systems. CHAOS (WOODBURY, N.Y.) 2024; 34:072102. [PMID: 38985967 DOI: 10.1063/5.0214733] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/19/2024] [Accepted: 06/21/2024] [Indexed: 07/12/2024]
Abstract
Real-world non-autonomous systems are open, out-of-equilibrium systems that evolve in and are driven by temporally varying environments. Such systems can show multiple timescale and transient dynamics together with transitions to very different and, at times, even disastrous dynamical regimes. Since such critical transitions disrupt the systems' intended or desired functionality, it is crucial to understand the underlying mechanisms, to identify precursors of such transitions, and to reliably detect them in time series of suitable system observables to enable forecasts. This review critically assesses the various steps of investigation involved in time-series-analysis-based detection of critical transitions in real-world non-autonomous systems: from the data recording to evaluating the reliability of offline and online detections. It will highlight pros and cons to stimulate further developments, which would be necessary to advance understanding and forecasting nonlinear behavior such as critical transitions in complex systems.
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Rousseau DD, Bagniewski W, Cheng H. A reliable benchmark of the last 640,000 years millennial climate variability. Sci Rep 2023; 13:22851. [PMID: 38129446 PMCID: PMC10739820 DOI: 10.1038/s41598-023-49115-z] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/27/2023] [Accepted: 12/04/2023] [Indexed: 12/23/2023] Open
Abstract
How often have past climates undergone abrupt transitions? While our understanding of millennial variability during the past 130,000 years is well established, with precise dates available, such information on previous climate cycles is limited. To address this question, we identified 196 abrupt transitions in the δ18O record of the well-dated Chinese composite speleothem for the last 640,000 years. These results correspond to abrupt changes in the strength of the East Asian Monsoon, which align with the Greenland stadials and interstadials observed in the North Atlantic region during the last 130,000 years before present. These precise dates of past abrupt climate changes constitute a reliable and necessary benchmark for Earth System models used to study future climate scenarios.
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Affiliation(s)
- Denis-Didier Rousseau
- Géosciences Montpellier, Université Montpellier, 34095, Montpellier, France.
- Division of Geochronology and Environmental Isotopes, Institute of Physics-CSE, Silesian University of Technology, 44-100, Gliwice, Poland.
- Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, 10964, USA.
| | - Witold Bagniewski
- Laboratoire de Météorologie Dynamique, École Normale Supérieure -Paris Sciences et Lettres University, 75005, Paris, France
| | - Hai Cheng
- Institute of Global Environmental Change, Xi'an Jiaotong University, Xi'an, 710049, China
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Rousseau DD, Bagniewski W, Lucarini V. A punctuated equilibrium analysis of the climate evolution of cenozoic exhibits a hierarchy of abrupt transitions. Sci Rep 2023; 13:11290. [PMID: 37438407 DOI: 10.1038/s41598-023-38454-6] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/08/2022] [Accepted: 07/08/2023] [Indexed: 07/14/2023] Open
Abstract
The Earth's climate has experienced numerous critical transitions during its history, which have often been accompanied by massive and rapid changes in the biosphere. Such transitions are evidenced in various proxy records covering different timescales. The goal is then to identify, date, characterize, and rank past critical transitions in terms of importance, thus possibly yielding a more thorough perspective on climatic history. To illustrate such an approach, which is inspired by the punctuated equilibrium perspective on the theory of evolution, we have analyzed 2 key high-resolution datasets: the CENOGRID marine compilation (past 66 Myr), and North Atlantic U1308 record (past 3.3 Myr). By combining recurrence analysis of the individual time series with a multivariate representation of the system based on the theory of the quasi-potential, we identify the key abrupt transitions associated with major regime changes that separate various clusters of climate variability. This allows interpreting the time-evolution of the system as a trajectory taking place in a dynamical landscape, whose multiscale features describe a hierarchy of metastable states and associated tipping points.
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Affiliation(s)
- Denis-Didier Rousseau
- Géosciences Montpellier, Université Montpellier, Montpellier, France.
- Institute of Physics-CSE, Division of Geochronology and Environmental Isotopes, Silesian University of Technology, Gliwice, Poland.
- Lamont Doherty Earth Observatory, Columbia University, Palisades, NY, USA.
| | - Witold Bagniewski
- Ecole Normale Supérieure-Paris Sciences et Lettres, Laboratoire de Météorologie Dynamique, Paris, France
| | - Valerio Lucarini
- Department of Mathematics and Statistics, University of Reading, Reading, UK
- Centre for the Mathematics of Planet Earth, University of Reading, Reading, UK
- School of Systems Science, Beijing Normal University, Beijing, People's Republic of China
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Bagniewski W, Rousseau DD, Ghil M. The PaleoJump database for abrupt transitions in past climates. Sci Rep 2023; 13:4472. [PMID: 36934110 PMCID: PMC10024733 DOI: 10.1038/s41598-023-30592-1] [Citation(s) in RCA: 3] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/08/2022] [Accepted: 02/27/2023] [Indexed: 03/20/2023] Open
Abstract
Tipping points (TPs) in Earth's climate system have been the subject of increasing interest and concern in recent years, given the risk that anthropogenic forcing could cause abrupt, potentially irreversible, climate transitions. Paleoclimate records are essential for identifying past TPs and for gaining a thorough understanding of the underlying nonlinearities and bifurcation mechanisms. However, the quality, resolution, and reliability of these records can vary, making it important to carefully select the ones that provide the most accurate representation of past climates. Moreover, as paleoclimate time series vary in their origin, time spans, and periodicities, an objective, automated methodology is crucial for identifying and comparing TPs. To address these challenges, we introduce the open-source PaleoJump database, which contains a collection of carefully selected, high-resolution records originating in ice cores, marine sediments, speleothems, terrestrial records, and lake sediments. These records describe climate variability on centennial, millennial and longer time scales and cover all the continents and ocean basins. We provide an overview of their spatial distribution and discuss the gaps in coverage. Our statistical methodology includes an augmented Kolmogorov-Smirnov test and Recurrence Quantification Analysis; it is applied here, for illustration purposes, to selected records in which abrupt transitions are automatically detected and the presence of potential tipping elements is investigated. These transitions are shown in the PaleoJump database along with other essential information about the records, including location, temporal scale and resolution, as well as temporal plots. This open-source database represents, therefore, a valuable resource for researchers investigating TPs in past climates.
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Affiliation(s)
- Witold Bagniewski
- Department of Geosciences and Laboratoire de Météorologie Dynamique (CNRS and IPSL), École Normale Supérieure, PSL University, Paris, France.
| | - Denis-Didier Rousseau
- Geosciences Montpellier, CNRS, University of Montpellier, Montpellier, France
- Institute of Physics - CSE, Division of Geochronology and Environmental Isotopes, Silesian University of Technology, Gliwice, Poland
- Lamont-Doherty Earth Observatory, Columbia University, New York, USA
| | - Michael Ghil
- Department of Geosciences and Laboratoire de Météorologie Dynamique (CNRS and IPSL), École Normale Supérieure, PSL University, Paris, France
- Department of Atmospheric and Oceanic Sciences, University of California at Los Angeles, Los Angeles, USA
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