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- Buoyancy forcing: a key driver of northern North Atlantic sea surface
temperature variability across multiple timescales
Abstract: Buoyancy forcing: a key driver of northern North Atlantic sea surface temperature variability across multiple timescales
Bjørg Risebrobakken, Mari F. Jensen, Helene R. Langehaug, Tor Eldevik, Anne Britt Sandø, Camille Li, Andreas Born, Erin Louise McClymont, Ulrich Salzmann, and Stijn De Schepper
Clim. Past, 19, 1101–1123, https://doi.org/10.5194/cp-19-1101-2023, 2023
In the observational period, spatially coherent sea surface temperatures characterize the northern North Atlantic at multidecadal timescales. We show that spatially non-coherent temperature patterns are seen both in further projections and a past warm climate period with a CO2 level comparable to the future low-emission scenario. Buoyancy forcing is shown to be important for northern North Atlantic temperature patterns.
PubDate: Thu, 01 Jun 2023 12:11:00 +020
DOI: 10.5194/cp-19-1101-2023 2023
- Atmospheric methane since the last glacial maximum was driven by wetland
sources
Abstract: Atmospheric methane since the last glacial maximum was driven by wetland sources
Thomas Kleinen, Sergey Gromov, Benedikt Steil, and Victor Brovkin
Clim. Past, 19, 1081–1099, https://doi.org/10.5194/cp-19-1081-2023, 2023
We modelled atmospheric methane continuously from the last glacial maximum to the present using a state-of-the-art Earth system model. Our model results compare well with reconstructions from ice cores and improve our understanding of a very intriguing period of Earth system history, the deglaciation, when atmospheric methane changed quickly and strongly. Deglacial methane changes are driven by emissions from tropical wetlands, with wetlands in high northern latitudes being secondary.
PubDate: Thu, 01 Jun 2023 12:11:00 +020
DOI: 10.5194/cp-19-1081-2023 2023
- CO2- and orbitally- driven oxygen isotope variability in the Early Eocene
Abstract: CO2- and orbitally- driven oxygen isotope variability in the Early Eocene
Julia Campbell, Christopher J. Poulsen, Jiang Zhu, Jessica E. Tierney, and Jeremy Keeler
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-37,2023
Preprint under review for CP (discussion: open, 0 comments)
In this study, we use climate modeling to investigate the relative impact of CO2 and orbit on Early Eocene (~55 million years ago) climate, as well as compare our modeled results to fossil records to determine the context for the Paleocene-Eocene Thermal Maximum, the most extreme hyperthermal in the Cenozoic. Our conclusions consider limitations and illustrate the importance of climate models when interpreting paleoclimate records in times of extreme warmth.
PubDate: Wed, 31 May 2023 12:11:00 +020
DOI: 10.5194/cp-2023-372023
- Refining data–data and data–model vegetation comparisons using the
Earth mover's distance (EMD)
Abstract: Refining data–data and data–model vegetation comparisons using the Earth mover's distance (EMD)
Manuel Chevalier, Anne Dallmeyer, Nils Weitzel, Chenzhi Li, Jean-Philippe Baudouin, Ulrike Herzschuh, Xianyong Cao, and Andreas Hense
Clim. Past, 19, 1043–1060, https://doi.org/10.5194/cp-19-1043-2023, 2023
Data–data and data–model vegetation comparisons are commonly based on comparing single vegetation estimates. While this approach generates good results on average, reducing pollen assemblages to single single plant functional type (PFT) or biome estimates can oversimplify the vegetation signal. We propose using a multivariate metric, the Earth mover's distance (EMD), to include more details about the vegetation structure when performing such comparisons.
PubDate: Tue, 30 May 2023 12:11:00 +020
DOI: 10.5194/cp-19-1043-2023 2023
- Deglacial and Holocene sea-ice and climate dynamics in the Bransfield
Strait, northern Antarctic Peninsula
Abstract: Deglacial and Holocene sea-ice and climate dynamics in the Bransfield Strait, northern Antarctic Peninsula
Maria-Elena Vorrath, Juliane Müller, Paola Cárdenas, Thomas Opel, Sebastian Mieruch, Oliver Esper, Lester Lembke-Jene, Johan Etourneau, Andrea Vieth-Hillebrand, Niko Lahajnar, Carina B. Lange, Amy Leventer, Dimitris Evangelinos, Carlota Escutia, and Gesine Mollenhauer
Clim. Past, 19, 1061–1079, https://doi.org/10.5194/cp-19-1061-2023, 2023
Sea ice is important to stabilize the ice sheet in Antarctica. To understand how the global climate and sea ice were related in the past we looked at ancient molecules (IPSO25) from sea-ice algae and other species whose dead cells accumulated on the ocean floor over time. With chemical analyses we could reconstruct the history of sea ice and ocean temperatures of the past 14 000 years. We found out that sea ice became less as the ocean warmed, and more phytoplankton grew towards today's level.
PubDate: Tue, 30 May 2023 12:11:00 +020
DOI: 10.5194/cp-19-1061-2023 2023
- Deglacial climate changes as forced by different ice sheet reconstructions
Abstract: Deglacial climate changes as forced by different ice sheet reconstructions
Nathaelle Bouttes, Fanny Lhardy, Aurélien Quiquet, Didier Paillard, Hugues Goosse, and Didier M. Roche
Clim. Past, 19, 1027–1042, https://doi.org/10.5194/cp-19-1027-2023, 2023
The last deglaciation is a period of large warming from 21 000 to 9000 years ago, concomitant with ice sheet melting. Here, we evaluate the impact of different ice sheet reconstructions and different processes linked to their changes. Changes in bathymetry and coastlines, although not often accounted for, cannot be neglected. Ice sheet melt results in freshwater into the ocean with large effects on ocean circulation, but the timing cannot explain the observed abrupt climate changes.
PubDate: Fri, 26 May 2023 09:36:39 +020
DOI: 10.5194/cp-19-1027-2023 2023
- BrGDGTs-based seasonal paleotemperature reconstruction for the last 15,000
years from a shallow lake on the eastern Tibetan Plateau
Abstract: BrGDGTs-based seasonal paleotemperature reconstruction for the last 15,000 years from a shallow lake on the eastern Tibetan Plateau
Xiaohuan Hou, Nannan Wang, Zhe Sun, Kan Yuan, Xianyong Cao, and Juzhi Hou
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-32,2023
Preprint under review for CP (discussion: open, 0 comments)
We present an ice-free season temperature based on brGDGTs over the last 15 ka on the eastern TP. The result shows that Holocene Thermal Maximum occurred during 8–3.5 ka, which lags behind pollen-based July temperature recorded in same sediment core, indicating a significant seasonal bias between different proxies. We also investigated previously published brGDGTs-based temperatures on TP to determine the pattern of Holocene temperature changes and possible reasons for the diverse records.
PubDate: Wed, 24 May 2023 09:36:39 +020
DOI: 10.5194/cp-2023-322023
- Resilient Antarctic monsoonal climate prevented ice growth during the
Eocene
Abstract: Resilient Antarctic monsoonal climate prevented ice growth during the Eocene
Michiel Baatsen, Peter Bijl, Anna von der Heydt, Appy Sluijs, and Henk Dijkstra
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-36,2023
Preprint under review for CP (discussion: open, 0 comments)
This work introduces the possibility and consequences of monsoons on Antarctica in the warm Eocene climate. We suggest that such a monsoonal climate can be important to understand conditions on Antarctica prior to large-scale glaciation. We can explain seemingly contradictory indications of ice and vegetation on the continent through regional variability. In addition, we provide a new mechanism through which most of Antarctica remained ice-free through a wide range of global climatic changes.
PubDate: Wed, 24 May 2023 09:36:39 +020
DOI: 10.5194/cp-2023-362023
- Nonlinear increase in seawater 87Sr/86Sr in the Oligocene to early Miocene
and implications for climate-sensitive weathering
Abstract: Nonlinear increase in seawater 87Sr/86Sr in the Oligocene to early Miocene and implications for climate-sensitive weathering
Heather M. Stoll, Leopoldo D. Pena, Ivan Hernandez-Almeida, José Guitián, Thomas Tanner, and Heiko Paelike
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-29,2023
Preprint under review for CP (discussion: open, 0 comments)
The Oligocene and Early Miocene periods featured dynamic glacial cycles on Antarctica. In this paper, we use Sr isotopes in marine carbonate sediments to document a change in the location and intensity of continental weathering during short periods of very intense Antartic glaciation. Potentially, the weathering intensity of old continental rocks on Antarctica was reduced during glaciation. We also show improved age models for correlation of Southern ocean and North Atlantic sediments.
PubDate: Tue, 23 May 2023 14:15:09 +020
DOI: 10.5194/cp-2023-292023
- Methane, ethane, and propane production in Greenland ice core samples and
a first isotopic characterization of excess methane
Abstract: Methane, ethane, and propane production in Greenland ice core samples and a first isotopic characterization of excess methane
Michaela Mühl, Jochen Schmitt, Barbara Seth, James E. Lee, Jon S. Edwards, Edward J. Brook, Thomas Blunier, and Hubertus Fischer
Clim. Past, 19, 999–1025, https://doi.org/10.5194/cp-19-999-2023, 2023
Our ice core measurements show that methane, ethane, and propane concentrations are significantly elevated above their past atmospheric background for Greenland ice samples containing mineral dust. The underlying co-production process happens during the classical discrete wet extraction of air from the ice sample and affects previous reconstructions of the inter-polar difference of methane as well as methane stable isotope records derived from dust-rich Greenland ice.
PubDate: Mon, 22 May 2023 14:15:09 +020
DOI: 10.5194/cp-19-999-2023 2023
- Do phenomenological dynamical paleoclimate models have physical similarity
with Nature' Seemingly, not all of them do
Abstract: Do phenomenological dynamical paleoclimate models have physical similarity with Nature' Seemingly, not all of them do
Mikhail Y. Verbitsky and Michel Crucifix
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-30,2023
Preprint under review for CP (discussion: open, 0 comments)
Are phenomenological dynamical paleoclimate models physically similar to Nature' We demonstrated that though they may be very accurate in reproducing empirical time series this is not sufficient to claim physical similarity with Nature until similarity parameters are considered. We suggest that the diagnostics of physical similarity should become a standard procedure before a phenomenological model can be utilized for interpretations of historical records or for future predictions.
PubDate: Mon, 22 May 2023 14:15:09 +020
DOI: 10.5194/cp-2023-302023
- A transient CGCM simulation of the past 3 million years
Abstract: A transient CGCM simulation of the past 3 million years
Kyung-Sook Yun, Axel Timmermann, Sun-Seon Lee, Matteo Willeit, Andrey Ganopolski, and Jyoti Jadhav
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-34,2023
Preprint under review for CP (discussion: open, 0 comments)
To quantify the sensitivity of the earth system to orbital-scale forcings we conducted an unprecedented quasi-continuous coupled general climate model simulation with the Community Earth System Model, which covers the climatic history of the past 3 million years ago. This study could stimulate future transient paleo-climate model simulations and perspectives to further highlight and document the effect of anthropogenic CO2 emissions in the broader paleo-climatic context.
PubDate: Mon, 22 May 2023 14:15:09 +020
DOI: 10.5194/cp-2023-342023
- Coccolithus pelagicus subsp. braarudii morphological plasticity in
response to variations in the Canary region upwelling system over the past
250 ka
Abstract: Coccolithus pelagicus subsp. braarudii morphological plasticity in response to variations in the Canary region upwelling system over the past 250 ka
Gonçalo Prista, Áurea Narciso, and Mário Cachão
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-31,2023
Preprint under review for CP (discussion: open, 0 comments)
Upwelling regions have great ecological, social, and economic importance, but predicting the effects of future climate change on upwelling systems is extremely difficult. One of the best tools we have is to look into the past and study their response to climate events. However, good proxies are hard to find due to different reasons. Here we show how using fossil coccolithophores, unicellular algae with calcified scales, is a promising tool, by using size variation to infer upwelling intensity.
PubDate: Tue, 16 May 2023 15:50:02 +020
DOI: 10.5194/cp-2023-312023
- The effect of uncertainties in natural forcing records on simulated
temperature during the last millennium
Abstract: The effect of uncertainties in natural forcing records on simulated temperature during the last millennium
Lucie J. Lücke, Andrew P. Schurer, Matthew Toohey, Lauren R. Marshall, and Gabriele C. Hegerl
Clim. Past, 19, 959–978, https://doi.org/10.5194/cp-19-959-2023, 2023
Evidence from tree rings and ice cores provides incomplete information about past volcanic eruptions and the Sun's activity. We model past climate with varying solar and volcanic scenarios and compare it to reconstructed temperature. We confirm that the Sun's influence was small and that uncertain volcanic activity can strongly influence temperature shortly after the eruption. On long timescales, independent data sources closely agree, increasing our confidence in understanding of past climate.
PubDate: Mon, 15 May 2023 15:50:02 +020
DOI: 10.5194/cp-19-959-2023 2023
- Environmental changes during the onset of the Late Pliensbachian Event
(Early Jurassic) in the Cardigan Bay Basin, Wales
Abstract: Environmental changes during the onset of the Late Pliensbachian Event (Early Jurassic) in the Cardigan Bay Basin, Wales
Teuntje P. Hollaar, Stephen P. Hesselbo, Jean-François Deconinck, Magret Damaschke, Clemens V. Ullmann, Mengjie Jiang, and Claire M. Belcher
Clim. Past, 19, 979–997, https://doi.org/10.5194/cp-19-979-2023, 2023
Palaeoclimatological reconstructions aid our understanding of current and future climate change. In the Pliensbachian (Early Jurassic) a climatic cooling event occurred globally. We show that this cooling event has a significant impact on the depositional environment of the Cardigan Bay basin but that the 405 kyr eccentricity cycle remained the dominant control on terrestrial and marine depositional processes.
PubDate: Mon, 15 May 2023 15:50:02 +020
DOI: 10.5194/cp-19-979-2023 2023
- Drought reconstruction since 1796 CE based on tree-ring widths in the
Upper Heilongjiang (Amur) River Basin in Northeast Asia, and its linkage
to Pacific Ocean climate variability
Abstract: Drought reconstruction since 1796 CE based on tree-ring widths in the Upper Heilongjiang (Amur) River Basin in Northeast Asia, and its linkage to Pacific Ocean climate variability
Yang Xu, Heli Zhang, Feng Chen, Shijie Wang, Mao Hu, Martín Hadad, and Fidel Roig
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-28,2023
Preprint under review for CP (discussion: open, 0 comments)
We reconstructed the monthly mean scPDSI for May–July in the Upper Heilongjiang (Amur) Basin since 1796. Our analysis suggests that the dry/wet variability in the Upper Heilongjiang (Amur) River Basin is related to several large-scale climate stresses and atmospheric circulation patterns (the ENSO and Silk Road models). the cause of drought is primarily a reduction in advective water vapor transport, rather than precipitation circulation processes.
PubDate: Wed, 10 May 2023 12:33:08 +020
DOI: 10.5194/cp-2023-282023
- Quantifying the contribution of forcing and three prominent modes of
variability to historical climate
Abstract: Quantifying the contribution of forcing and three prominent modes of variability to historical climate
Andrew P. Schurer, Gabriele C. Hegerl, Hugues Goosse, Massimo A. Bollasina, Matthew H. England, Michael J. Mineter, Doug M. Smith, and Simon F. B. Tett
Clim. Past, 19, 943–957, https://doi.org/10.5194/cp-19-943-2023, 2023
We adopt an existing data assimilation technique to constrain a model simulation to follow three important modes of variability, the North Atlantic Oscillation, El Niño–Southern Oscillation and the Southern Annular Mode. How it compares to the observed climate is evaluated, with improvements over simulations without data assimilation found over many regions, particularly the tropics, the North Atlantic and Europe, and discrepancies with global cooling following volcanic eruptions are reconciled.
PubDate: Tue, 09 May 2023 12:33:08 +020
DOI: 10.5194/cp-19-943-2023 2023
- Dansgaard–Oeschger events in climate models: review and baseline Marine
Isotope Stage 3 (MIS3) protocol
Abstract: Dansgaard–Oeschger events in climate models: review and baseline Marine Isotope Stage 3 (MIS3) protocol
Irene Malmierca-Vallet, Louise C. Sime, and the D–O community members
Clim. Past, 19, 915–942, https://doi.org/10.5194/cp-19-915-2023, 2023
Greenland ice core records feature Dansgaard–Oeschger (D–O) events, abrupt warming episodes followed by a gradual-cooling phase during mid-glacial periods. There is uncertainty whether current climate models can effectively represent the processes that cause D–O events. Here, we propose a Marine Isotopic Stage 3 (MIS3) baseline protocol which is intended to provide modelling groups investigating D–O oscillations with a common framework.
PubDate: Mon, 08 May 2023 12:33:08 +020
DOI: 10.5194/cp-19-915-2023 2023
- Miocene Antarctic ice sheet area responds significantly faster than volume
to CO2-induced climate change
Abstract: Miocene Antarctic ice sheet area responds significantly faster than volume to CO2-induced climate change
Lennert B. Stap, Constantijn J. Berends, and Roderik S. W. van de Wal
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-12,2023
Preprint under review for CP (discussion: open, 0 comments)
Analyzing simulations of Antarctic ice sheet variability during the early and mid-Miocene (23 to 14 million years ago), we find that the ice sheet area responds faster and more strongly than volume to climate change on quasi-orbital timescales. Considering the recent discovery that ice area, rather than volume, influences deep ocean temperatures, this implies that the Miocene Antarctic ice sheet affects deep ocean temperatures more than its volume suggests.
PubDate: Mon, 08 May 2023 12:33:08 +020
DOI: 10.5194/cp-2023-122023
- Climate and Disease: the connection between temperature values and
precipitation rates and the probability of death due to waterborne and
airborne diseases in historical urban space (the evidence from Poznań,
Poland)
Abstract: Climate and Disease: the connection between temperature values and precipitation rates and the probability of death due to waterborne and airborne diseases in historical urban space (the evidence from Poznań, Poland)
Grażyna Liczbińska, Jörg Peter Vögele, and Marek Brabec
Clim. Past Discuss., https//doi.org/10.5194/cp-2023-26,2023
Preprint under review for CP (discussion: open, 0 comments)
The study examines the relationship between temperature values and precipitation rates as explanatory variables and the probability of death due to waterborne, airborne, and other diseases in historical urban space. So far, the literature has not been focused on epidemiology of 19th -century Polish urban areas in climatological context. We used individual data on mortality from Poznań parish death registers for 1850–1900. We studied the relationship between weather conditions and mortality.
PubDate: Mon, 08 May 2023 12:33:08 +020
DOI: 10.5194/cp-2023-262023
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