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Witkowski CR, von der Heydt AS, Valdes PJ, van der Meer MTJ, Schouten S, Sinninghe Damsté JS. Continuous sterane and phytane δ 13C record reveals a substantial pCO 2 decline since the mid-Miocene. Nat Commun 2024; 15:5192. [PMID: 38890288 PMCID: PMC11189397 DOI: 10.1038/s41467-024-47676-9] [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: 02/07/2022] [Accepted: 04/08/2024] [Indexed: 06/20/2024] Open
Abstract
Constraining the relationship between temperature and atmospheric concentrations of carbon dioxide (pCO2) is essential to model near-future climate. Here, we reconstruct pCO2 values over the past 15 million years (Myr), providing a series of analogues for possible near-future temperatures and pCO2, from a single continuous site (DSDP Site 467, California coast). We reconstruct pCO2 values using sterane and phytane, compounds that many phytoplankton produce and then become fossilised in sediment. From 15.0-0.3 Myr ago, our reconstructed pCO2 values steadily decline from 650 ± 150 to 280 ± 75 ppmv, mirroring global temperature decline. Using our new range of pCO2 values, we calculate average Earth system sensitivity and equilibrium climate sensitivity, resulting in 13.9 °C and 7.2 °C per doubling of pCO2, respectively. These values are significantly higher than IPCC global warming estimations, consistent or higher than some recent state-of-the-art climate models, and consistent with other proxy-based estimates.
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Affiliation(s)
- Caitlyn R Witkowski
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Burg (Texel), 1790AB, The Netherlands.
- Schools of Earth Science and Chemistry, and the Cabot Institute, University of Bristol, Bristol, BS8 1RJ, UK.
| | - Anna S von der Heydt
- Institute for Marine and Atmospheric Research Utrecht, Department of Physics, Utrecht University, Utrecht, 3584CC, The Netherlands
| | - Paul J Valdes
- School of Geographical Sciences and Cabot Institute, University of Bristol, Bristol, BS8 1SS, UK
| | - Marcel T J van der Meer
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Burg (Texel), 1790AB, The Netherlands
| | - Stefan Schouten
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Burg (Texel), 1790AB, The Netherlands
- Department of Geosciences, Utrecht University, Utrecht, 3508 TA, The Netherlands
| | - Jaap S Sinninghe Damsté
- Department of Marine Microbiology and Biogeochemistry, NIOZ Royal Netherlands Institute for Sea Research, Den Burg (Texel), 1790AB, The Netherlands
- Department of Geosciences, Utrecht University, Utrecht, 3508 TA, The Netherlands
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2
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Wilson LN, Gardner JD, Wilson JP, Farnsworth A, Perry ZR, Druckenmiller PS, Erickson GM, Organ CL. Global latitudinal gradients and the evolution of body size in dinosaurs and mammals. Nat Commun 2024; 15:2864. [PMID: 38580657 PMCID: PMC10997647 DOI: 10.1038/s41467-024-46843-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/05/2024] [Accepted: 03/12/2024] [Indexed: 04/07/2024] Open
Abstract
Global climate patterns fundamentally shape the distribution of species and ecosystems. For example, Bergmann's rule predicts that homeothermic animals, including birds and mammals, inhabiting cooler climates are generally larger than close relatives from warmer climates. The modern world, however, lacks the comparative data needed to evaluate such macroecological rules rigorously. Here, we test for Bergmann's rule in Mesozoic dinosaurs and mammaliaforms that radiated within relatively temperate global climate regimes. We develop a phylogenetic model that accounts for biases in the fossil record and allows for variable evolutionary dispersal rates. Our analysis also includes new fossil data from the extreme high-latitude Late Cretaceous Arctic Prince Creek Formation. We find no evidence for Bergmann's rule in Mesozoic dinosaurs or mammaliaforms, the ancestors of extant homeothermic birds and mammals. When our model is applied to thousands of extant dinosaur (bird) and mammal species, we find that body size evolution remains independent of latitude. A modest temperature effect is found in extant, but not in Mesozoic, birds, suggesting that body size evolution in modern birds was influenced by Bergmann's rule during Cenozoic climatic change. Our study provides a general approach for studying macroecological rules, highlighting the fossil record's power to address longstanding ecological principles.
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Affiliation(s)
- Lauren N Wilson
- University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK, 99775, USA.
- Department of Geosciences, University of Alaska, Fairbanks, AK, 99775, USA.
| | - Jacob D Gardner
- School of Biological Sciences, University of Reading, Reading, RG6 6EX, UK.
| | - John P Wilson
- Department of Earth Sciences, Montana State University, Bozeman, MT, 59715, USA
| | - Alex Farnsworth
- School of Geographical Sciences, University of Bristol, University Road, Bristol, BS8 1RL, UK
- State Key Laboratory of Tibetan Plateau Earth System, Resources and Environment (TPESRE), Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, 100101, China
| | - Zackary R Perry
- University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK, 99775, USA
- Department of Geosciences, University of Alaska, Fairbanks, AK, 99775, USA
| | - Patrick S Druckenmiller
- University of Alaska Museum, 1962 Yukon Drive, Fairbanks, AK, 99775, USA
- Department of Geosciences, University of Alaska, Fairbanks, AK, 99775, USA
| | - Gregory M Erickson
- Department of Biological Science, Florida State University, Tallahassee, FL, 32306, USA
| | - Chris L Organ
- School of Biological Sciences, University of Reading, Reading, RG6 6EX, UK.
- Department of Earth Sciences, Montana State University, Bozeman, MT, 59715, USA.
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3
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Malanoski CM, Farnsworth A, Lunt DJ, Valdes PJ, Saupe EE. Climate change is an important predictor of extinction risk on macroevolutionary timescales. Science 2024; 383:1130-1134. [PMID: 38452067 DOI: 10.1126/science.adj5763] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/11/2023] [Accepted: 01/29/2024] [Indexed: 03/09/2024]
Abstract
Anthropogenic climate change is increasing rapidly and already impacting biodiversity. Despite its importance in future projections, understanding of the underlying mechanisms by which climate mediates extinction remains limited. We present an integrated approach examining the role of intrinsic traits versus extrinsic climate change in mediating extinction risk for marine invertebrates over the past 485 million years. We found that a combination of physiological traits and the magnitude of climate change is necessary to explain marine invertebrate extinction patterns. Our results suggest that taxa previously identified as extinction resistant may still succumb to extinction if the magnitude of climate change is great enough.
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Affiliation(s)
- Cooper M Malanoski
- Department of Earth Sciences, Oxford University, South Parks Road, Oxford OX1 3AN, UK
| | - Alex Farnsworth
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | - Daniel J Lunt
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | - Paul J Valdes
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | - Erin E Saupe
- Department of Earth Sciences, Oxford University, South Parks Road, Oxford OX1 3AN, UK
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4
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Fenton IS, Aze T, Farnsworth A, Valdes P, Saupe EE. Origination of the modern-style diversity gradient 15 million years ago. Nature 2023; 614:708-712. [PMID: 36792825 DOI: 10.1038/s41586-023-05712-6] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/04/2022] [Accepted: 01/06/2023] [Indexed: 02/17/2023]
Abstract
The latitudinal diversity gradient (LDG) is a prevalent feature of modern ecosystems across diverse clades1-4. Recognized for well over a century, the causal mechanisms for LDGs remain disputed, in part because numerous putative drivers simultaneously covary with latitude1,3,5. The past provides the opportunity to disentangle LDG mechanisms because the relationships among biodiversity, latitude and possible causal factors have varied over time6-9. Here we quantify the emergence of the LDG in planktonic foraminifera at high spatiotemporal resolution over the past 40 million years, finding that a modern-style gradient arose only 15 million years ago. Spatial and temporal models suggest that LDGs for planktonic foraminifera may be controlled by the physical structure of the water column. Steepening of the latitudinal temperature gradient over 15 million years ago, associated with an increased vertical temperature gradient at low latitudes, may have enhanced niche partitioning and provided more opportunities for speciation at low latitudes. Supporting this hypothesis, we find that higher rates of low-latitude speciation steepened the diversity gradient, consistent with spatiotemporal patterns of depth partitioning by planktonic foraminifera. Extirpation of species from high latitudes also strengthened the LDG, but this effect tended to be weaker than speciation. Our results provide a step change in understanding the evolution of marine LDGs over long timescales.
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Affiliation(s)
- Isabel S Fenton
- Department of Earth Sciences, University of Oxford, Oxford, UK
| | - Tracy Aze
- School of Earth and Environment, University of Leeds, Leeds, UK
| | - Alexander Farnsworth
- School of Geographical Sciences, University of Bristol, Bristol, UK.,State Key Laboratory of Tibetan Plateau Earth System, Environment and Resources, Institute of Tibetan Plateau Research, Chinese Academy of Sciences, Beijing, China
| | - Paul Valdes
- School of Geographical Sciences, University of Bristol, Bristol, UK
| | - Erin E Saupe
- Department of Earth Sciences, University of Oxford, Oxford, UK.
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5
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Burls N, Sagoo N. Increasingly Sophisticated Climate Models Need the Out-Of-Sample Tests Paleoclimates Provide. JOURNAL OF ADVANCES IN MODELING EARTH SYSTEMS 2022; 14:e2022MS003389. [PMID: 37035628 PMCID: PMC10078273 DOI: 10.1029/2022ms003389] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 09/12/2022] [Revised: 11/28/2022] [Accepted: 12/05/2022] [Indexed: 06/19/2023]
Abstract
Climate models are becoming increasingly sophisticated as climate scientists continually work to improve the realism with which the processes influencing Earth's climate are represented. One example is the treatment of cloud microphysics: as complexity is added to cloud microphysical schemes, Earth's energy budget can respond to changes in climate forcings, such as carbon dioxide or aerosols, in new ways. This increase in degrees of freedom has illuminated larger spread in climate sensitivity across the latest generation of climate models participating Coupled Model Intercomparison Project, Phase 6, with more high climate sensitivity models (Zelinka et al., 2020, https://doi.org/10.1029/2019gl085782). Whilst the historical record gives us just over a century of data to apply toward climate sensitivity constraints (e.g., Nijsse et al., 2020, https://doi.org/10.5194/esd-11-737-2020), the ocean is still taking up much of the heat trapped by anthropogenic greenhouse gas emissions and the climate system is far from equilibrium which limits our understanding how climate sensitivity might change in response to long-term forced climate change. Here we discuss the valuable tests that paleoclimate reconstructions can provide the latest generation of climate models, as demonstrated by the recent study of Zhu et al., 2022, https://doi.org/10.1029/2021ms002776. Their study provides an example of the benefits for climate model development when climate models are confronted with simulating climates very different from today. Ideally the climate model development stage under future iterations of CMIP will involve such tests as an effort to constrain global climate sensitivity and the regional patterns of climate, such as polar amplification and subtropical aridification.
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Affiliation(s)
- Natalie Burls
- Department of Atmospheric, Oceanic, and Earth SciencesCenter for Ocean‐Land‐Atmosphere StudiesGeorge Mason UniversityVAFairfaxUSA
| | - Navjit Sagoo
- Department of MeteorologyStockholm UniversityStockholmSweden
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6
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Couvreur TL, Dauby G, Blach‐Overgaard A, Deblauwe V, Dessein S, Droissart V, Hardy OJ, Harris DJ, Janssens SB, Ley AC, Mackinder BA, Sonké B, Sosef MS, Stévart T, Svenning J, Wieringa JJ, Faye A, Missoup AD, Tolley KA, Nicolas V, Ntie S, Fluteau F, Robin C, Guillocheau F, Barboni D, Sepulchre P. Tectonics, climate and the diversification of the tropical African terrestrial flora and fauna. Biol Rev Camb Philos Soc 2021; 96:16-51. [PMID: 32924323 PMCID: PMC7821006 DOI: 10.1111/brv.12644] [Citation(s) in RCA: 54] [Impact Index Per Article: 18.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/20/2020] [Revised: 08/07/2020] [Accepted: 08/13/2020] [Indexed: 12/30/2022]
Abstract
Tropical Africa is home to an astonishing biodiversity occurring in a variety of ecosystems. Past climatic change and geological events have impacted the evolution and diversification of this biodiversity. During the last two decades, around 90 dated molecular phylogenies of different clades across animals and plants have been published leading to an increased understanding of the diversification and speciation processes generating tropical African biodiversity. In parallel, extended geological and palaeoclimatic records together with detailed numerical simulations have refined our understanding of past geological and climatic changes in Africa. To date, these important advances have not been reviewed within a common framework. Here, we critically review and synthesize African climate, tectonics and terrestrial biodiversity evolution throughout the Cenozoic to the mid-Pleistocene, drawing on recent advances in Earth and life sciences. We first review six major geo-climatic periods defining tropical African biodiversity diversification by synthesizing 89 dated molecular phylogeny studies. Two major geo-climatic factors impacting the diversification of the sub-Saharan biota are highlighted. First, Africa underwent numerous climatic fluctuations at ancient and more recent timescales, with tectonic, greenhouse gas, and orbital forcing stimulating diversification. Second, increased aridification since the Late Eocene led to important extinction events, but also provided unique diversification opportunities shaping the current tropical African biodiversity landscape. We then review diversification studies of tropical terrestrial animal and plant clades and discuss three major models of speciation: (i) geographic speciation via vicariance (allopatry); (ii) ecological speciation impacted by climate and geological changes, and (iii) genomic speciation via genome duplication. Geographic speciation has been the most widely documented to date and is a common speciation model across tropical Africa. We conclude with four important challenges faced by tropical African biodiversity research: (i) to increase knowledge by gathering basic and fundamental biodiversity information; (ii) to improve modelling of African geophysical evolution throughout the Cenozoic via better constraints and downscaling approaches; (iii) to increase the precision of phylogenetic reconstruction and molecular dating of tropical African clades by using next generation sequencing approaches together with better fossil calibrations; (iv) finally, as done here, to integrate data better from Earth and life sciences by focusing on the interdisciplinary study of the evolution of tropical African biodiversity in a wider geodiversity context.
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Affiliation(s)
| | - Gilles Dauby
- AMAP Lab, IRD, CIRAD, CNRS, INRAUniversity of MontpellierMontpellierFrance
- Laboratoire d'évolution Biologique et Ecologie, Faculté des SciencesUniversité Libre de BruxellesCP160/12, Avenue F.D. Roosevelt 50Brussels1050Belgium
| | - Anne Blach‐Overgaard
- Section for Ecoinformatics & Biodiversity, Department of BiologyAarhus UniversityNy Munkegade 114Aarhus CDK‐8000Denmark
- Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of BiologyAarhus UniversityNy Munkegade 114Aarhus CDK‐8000Denmark
| | - Vincent Deblauwe
- Center for Tropical Research (CTR), Institute of the Environment and SustainabilityUniversity of California, Los Angeles (UCLA)Los AngelesCA90095U.S.A.
- International Institute of Tropical Agriculture (IITA)YaoundéCameroon
| | | | - Vincent Droissart
- AMAP Lab, IRD, CIRAD, CNRS, INRAUniversity of MontpellierMontpellierFrance
- Laboratoire de Botanique Systématique et d'Écologie, École Normale SupérieureUniversité de Yaoundé IPO Box 047YaoundéCameroon
- Herbarium et Bibliothèque de Botanique AfricaineUniversité Libre de BruxellesBoulevard du TriompheBrusselsB‐1050Belgium
- Africa & Madagascar DepartmentMissouri Botanical GardenSt. LouisMOU.S.A.
| | - Oliver J. Hardy
- Laboratoire d'évolution Biologique et Ecologie, Faculté des SciencesUniversité Libre de BruxellesCP160/12, Avenue F.D. Roosevelt 50Brussels1050Belgium
| | - David J. Harris
- Royal Botanic Garden Edinburgh20A Inverleith RowEdinburghU.K.
| | | | - Alexandra C. Ley
- Institut für Geobotanik und Botanischer GartenUniversity Halle‐WittenbergNeuwerk 21Halle06108Germany
| | | | - Bonaventure Sonké
- Laboratoire de Botanique Systématique et d'Écologie, École Normale SupérieureUniversité de Yaoundé IPO Box 047YaoundéCameroon
| | | | - Tariq Stévart
- Herbarium et Bibliothèque de Botanique AfricaineUniversité Libre de BruxellesBoulevard du TriompheBrusselsB‐1050Belgium
- Africa & Madagascar DepartmentMissouri Botanical GardenSt. LouisMOU.S.A.
| | - Jens‐Christian Svenning
- Section for Ecoinformatics & Biodiversity, Department of BiologyAarhus UniversityNy Munkegade 114Aarhus CDK‐8000Denmark
- Center for Biodiversity Dynamics in a Changing World (BIOCHANGE), Department of BiologyAarhus UniversityNy Munkegade 114Aarhus CDK‐8000Denmark
| | - Jan J. Wieringa
- Naturalis Biodiversity CenterDarwinweg 2Leiden2333 CRThe Netherlands
| | - Adama Faye
- Laboratoire National de Recherches sur les Productions Végétales (LNRPV)Institut Sénégalais de Recherches Agricoles (ISRA)Route des Hydrocarbures, Bel Air BP 1386‐ CP18524DakarSenegal
| | - Alain D. Missoup
- Zoology Unit, Laboratory of Biology and Physiology of Animal Organisms, Faculty of ScienceUniversity of DoualaPO Box 24157DoualaCameroon
| | - Krystal A. Tolley
- South African National Biodiversity InstituteKirstenbosch Research CentrePrivate Bag X7, ClaremontCape Town7735South Africa
- School of Animal, Plant and Environmental SciencesUniversity of the WitwatersrandPrivate Bag 3Wits2050South Africa
| | - Violaine Nicolas
- Institut de Systématique, Evolution, Biodiversité (ISYEB), Muséum national d'Histoire naturelle, CNRS, Sorbonne Université, EPHEUniversité des AntillesCP51, 57 rue CuvierParis75005France
| | - Stéphan Ntie
- Département de Biologie, Faculté des SciencesUniversité des Sciences et Techniques de MasukuFrancevilleBP 941Gabon
| | - Frédiéric Fluteau
- Institut de Physique du Globe de Paris, CNRSUniversité de ParisParisF‐75005France
| | - Cécile Robin
- CNRS, Géosciences Rennes, UMR6118University of RennesRennes35042France
| | | | - Doris Barboni
- CEREGE, Aix‐Marseille University, CNRS, IRD, Collège de France, INRA, Technopole Arbois MéditerranéeBP80Aix‐en‐Provence cedex413545France
| | - Pierre Sepulchre
- Laboratoire des Sciences du Climat et de l'Environnement, LSCE/IPSL, CEA‐CNRS‐UVSQUniversité Paris‐SaclayGif‐sur‐YvetteF‐91191France
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7
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Polar amplification of Pliocene climate by elevated trace gas radiative forcing. Proc Natl Acad Sci U S A 2020; 117:23401-23407. [PMID: 32887804 DOI: 10.1073/pnas.2002320117] [Citation(s) in RCA: 9] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Warm periods in Earth's history offer opportunities to understand the dynamics of the Earth system under conditions that are similar to those expected in the near future. The Middle Pliocene warm period (MPWP), from 3.3 to 3.0 My B.P, is the most recent time when atmospheric CO2 levels were as high as today. However, climate model simulations of the Pliocene underestimate high-latitude warming that has been reconstructed from fossil pollen samples and other geological archives. One possible reason for this is that enhanced non-CO2 trace gas radiative forcing during the Pliocene, including from methane (CH4), has not been included in modeling. We use a suite of terrestrial biogeochemistry models forced with MPWP climate model simulations from four different climate models to produce a comprehensive reconstruction of the MPWP CH4 cycle, including uncertainty. We simulate an atmospheric CH4 mixing ratio of 1,000 to 1,200 ppbv, which in combination with estimates of radiative forcing from N2O and O3, contributes a non-CO2 radiative forcing of 0.9 [Formula: see text] (range 0.6 to 1.1), which is 43% (range 36 to 56%) of the CO2 radiative forcing used in MPWP climate simulations. This additional forcing would cause a global surface temperature increase of 0.6 to 1.0 °C, with amplified changes at high latitudes, improving agreement with geological evidence of Middle Pliocene climate. We conclude that natural trace gas feedbacks are critical for interpreting climate warmth during the Pliocene and potentially many other warm phases of the Cenezoic. These results also imply that using Pliocene CO2 and temperature reconstructions alone may lead to overestimates of the fast or Charney climate sensitivity.
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8
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Zhu J, Poulsen CJ, Tierney JE. Simulation of Eocene extreme warmth and high climate sensitivity through cloud feedbacks. SCIENCE ADVANCES 2019; 5:eaax1874. [PMID: 31555736 PMCID: PMC6750925 DOI: 10.1126/sciadv.aax1874] [Citation(s) in RCA: 12] [Impact Index Per Article: 2.4] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 02/28/2019] [Accepted: 08/20/2019] [Indexed: 06/10/2023]
Abstract
The Early Eocene, a period of elevated atmospheric CO2 (>1000 ppmv), is considered an analog for future climate. Previous modeling attempts have been unable to reproduce major features of Eocene climate indicated by proxy data without substantial modification to the model physics. Here, we present simulations using a state-of-the-art climate model forced by proxy-estimated CO2 levels that capture the extreme surface warmth and reduced latitudinal temperature gradient of the Early Eocene and the warming of the Paleocene-Eocene Thermal Maximum. Our simulations exhibit increasing equilibrium climate sensitivity with warming and suggest an Eocene sensitivity of more than 6.6°C, much greater than the present-day value (4.2°C). This higher climate sensitivity is mainly attributable to the shortwave cloud feedback, which is linked primarily to cloud microphysical processes. Our findings highlight the role of small-scale cloud processes in determining large-scale climate changes and suggest a potential increase in climate sensitivity with future warming.
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Affiliation(s)
- Jiang Zhu
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Christopher J. Poulsen
- Department of Earth and Environmental Sciences, University of Michigan, Ann Arbor, MI 48109, USA
| | - Jessica E. Tierney
- Department of Geosciences, The University of Arizona, Tucson, AZ 85721, USA
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9
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Climatic shifts drove major contractions in avian latitudinal distributions throughout the Cenozoic. Proc Natl Acad Sci U S A 2019; 116:12895-12900. [PMID: 31182570 DOI: 10.1073/pnas.1903866116] [Citation(s) in RCA: 26] [Impact Index Per Article: 5.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Many higher level avian clades are restricted to Earth's lower latitudes, leading to historical biogeographic reconstructions favoring a Gondwanan origin of crown birds and numerous deep subclades. However, several such "tropical-restricted" clades (TRCs) are represented by stem-lineage fossils well outside the ranges of their closest living relatives, often on northern continents. To assess the drivers of these geographic disjunctions, we combined ecological niche modeling, paleoclimate models, and the early Cenozoic fossil record to examine the influence of climatic change on avian geographic distributions over the last ∼56 million years. By modeling the distribution of suitable habitable area through time, we illustrate that most Paleogene fossil-bearing localities would have been suitable for occupancy by extant TRC representatives when their stem-lineage fossils were deposited. Potentially suitable habitat for these TRCs is inferred to have become progressively restricted toward the tropics throughout the Cenozoic, culminating in relatively narrow circumtropical distributions in the present day. Our results are consistent with coarse-scale niche conservatism at the clade level and support a scenario whereby climate change over geological timescales has largely dictated the geographic distributions of many major avian clades. The distinctive modern bias toward high avian diversity at tropical latitudes for most hierarchical taxonomic levels may therefore represent a relatively recent phenomenon, overprinting a complex biogeographic history of dramatic geographic range shifts driven by Earth's changing climate, variable persistence, and intercontinental dispersal. Earth's current climatic trajectory portends a return to a megathermal state, which may dramatically influence the geographic distributions of many range-restricted extant clades.
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10
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Eocene greenhouse climate revealed by coupled clumped isotope-Mg/Ca thermometry. Proc Natl Acad Sci U S A 2018; 115:1174-1179. [PMID: 29358374 DOI: 10.1073/pnas.1714744115] [Citation(s) in RCA: 34] [Impact Index Per Article: 5.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/18/2022] Open
Abstract
Past greenhouse periods with elevated atmospheric CO2 were characterized by globally warmer sea-surface temperatures (SST). However, the extent to which the high latitudes warmed to a greater degree than the tropics (polar amplification) remains poorly constrained, in particular because there are only a few temperature reconstructions from the tropics. Consequently, the relationship between increased CO2, the degree of tropical warming, and the resulting latitudinal SST gradient is not well known. Here, we present coupled clumped isotope (Δ47)-Mg/Ca measurements of foraminifera from a set of globally distributed sites in the tropics and midlatitudes. Δ47 is insensitive to seawater chemistry and therefore provides a robust constraint on tropical SST. Crucially, coupling these data with Mg/Ca measurements allows the precise reconstruction of Mg/Casw throughout the Eocene, enabling the reinterpretation of all planktonic foraminifera Mg/Ca data. The combined dataset constrains the range in Eocene tropical SST to 30-36 °C (from sites in all basins). We compare these accurate tropical SST to deep-ocean temperatures, serving as a minimum constraint on high-latitude SST. This results in a robust conservative reconstruction of the early Eocene latitudinal gradient, which was reduced by at least 32 ± 10% compared with present day, demonstrating greater polar amplification than captured by most climate models.
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11
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Fenton IS, Pearson PN, Dunkley Jones T, Farnsworth A, Lunt DJ, Markwick P, Purvis A. The impact of Cenozoic cooling on assemblage diversity in planktonic foraminifera. Philos Trans R Soc Lond B Biol Sci 2016; 371:20150224. [PMID: 26977064 PMCID: PMC4810817 DOI: 10.1098/rstb.2015.0224] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.8] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/31/2022] Open
Abstract
The Cenozoic planktonic foraminifera (PF) (calcareous zooplankton) have arguably the most detailed fossil record of any group. The quality of this record allows models of environmental controls on macroecology, developed for Recent assemblages, to be tested on intervals with profoundly different climatic conditions. These analyses shed light on the role of long-term global cooling in establishing the modern latitudinal diversity gradient (LDG)--one of the most powerful generalizations in biogeography and macroecology. Here, we test the transferability of environment-diversity models developed for modern PF assemblages to the Eocene epoch (approx. 56-34 Ma), a time of pronounced global warmth. Environmental variables from global climate models are combined with Recent environment-diversity models to predict Eocene richness gradients, which are then compared with observed patterns. The results indicate the modern LDG--lower richness towards the poles--developed through the Eocene. Three possible causes are suggested for the mismatch between statistical model predictions and data in the Early Eocene: the environmental estimates are inaccurate, the statistical model misses a relevant variable, or the intercorrelations among facets of diversity--e.g. richness, evenness, functional diversity--have changed over geological time. By the Late Eocene, environment-diversity relationships were much more similar to those found today.
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Affiliation(s)
- Isabel S Fenton
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
| | - Paul N Pearson
- School of Earth and Ocean Sciences, Cardiff University, Cardiff CF10 3AT, UK
| | - Tom Dunkley Jones
- School of Geography, Earth and Environmental Sciences, University of Birmingham, Edgbaston, Birmingham B15 2TT, UK
| | - Alexander Farnsworth
- School of Geographical Sciences and Cabot Institute, University of Bristol, Bristol BS8 1SS, UK
| | - Daniel J Lunt
- School of Geographical Sciences and Cabot Institute, University of Bristol, Bristol BS8 1SS, UK
| | - Paul Markwick
- Getech Group plc. Elmete Hall, Elmete Lane, Leeds LS8 2LJ, UK
| | - Andy Purvis
- Department of Life Sciences, Natural History Museum, Cromwell Road, London SW7 5BD, UK Department of Life Sciences, Imperial College London, Silwood Park Campus, Ascot SL5 7PY, UK
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Lunt DJ, Elderfield H, Pancost R, Ridgwell A, Foster GL, Haywood A, Kiehl J, Sagoo N, Shields C, Stone EJ, Valdes P. Warm climates of the past--a lesson for the future? PHILOSOPHICAL TRANSACTIONS. SERIES A, MATHEMATICAL, PHYSICAL, AND ENGINEERING SCIENCES 2013; 371:20130146. [PMID: 24043873 PMCID: PMC3785815 DOI: 10.1098/rsta.2013.0146] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/25/2023]
Abstract
This Discussion Meeting Issue of the Philosophical Transactions A had its genesis in a Discussion Meeting of the Royal Society which took place on 10-11 October 2011. The Discussion Meeting, entitled 'Warm climates of the past: a lesson for the future?', brought together 16 eminent international speakers from the field of palaeoclimate, and was attended by over 280 scientists and members of the public. Many of the speakers have contributed to the papers compiled in this Discussion Meeting Issue. The papers summarize the talks at the meeting, and present further or related work. This Discussion Meeting Issue asks to what extent information gleaned from the study of past climates can aid our understanding of future climate change. Climate change is currently an issue at the forefront of environmental science, and also has important sociological and political implications. Most future predictions are carried out by complex numerical models; however, these models cannot be rigorously tested for scenarios outside of the modern, without making use of past climate data. Furthermore, past climate data can inform our understanding of how the Earth system operates, and can provide important contextual information related to environmental change. All past time periods can be useful in this context; here, we focus on past climates that were warmer than the modern climate, as these are likely to be the most similar to the future. This introductory paper is not meant as a comprehensive overview of all work in this field. Instead, it gives an introduction to the important issues therein, using the papers in this Discussion Meeting Issue, and other works from all the Discussion Meeting speakers, as exemplars of the various ways in which past climates can inform projections of future climate. Furthermore, we present new work that uses a palaeo constraint to quantitatively inform projections of future equilibrium ice sheet change.
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Affiliation(s)
- D. J. Lunt
- Cabot Institute, and School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - H. Elderfield
- Department of Earth Sciences, University of Cambridge, Downing Street, Cambridge CB2 3EQ, UK
| | - R. Pancost
- Cabot Institute, and School of Chemistry, University of Bristol, Cantock's Close, Bristol BS8 1TS, UK
| | - A. Ridgwell
- Cabot Institute, and School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - G. L. Foster
- Ocean and Earth Science, University of Southampton, European Way, Southampton SO14 3ZH, UK
| | - A. Haywood
- School of Earth and Environment, University of Leeds, Woodhouse Lane, Leeds LS2 9JT, UK
| | - J. Kiehl
- Climate and Global Dynamics, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305, USA
| | - N. Sagoo
- Cabot Institute, and School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - C. Shields
- Climate and Global Dynamics, National Center for Atmospheric Research, 1850 Table Mesa Drive, Boulder, CO 80305, USA
| | - E. J. Stone
- Cabot Institute, and School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
| | - P. Valdes
- Cabot Institute, and School of Geographical Sciences, University of Bristol, University Road, Bristol BS8 1SS, UK
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