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- Closing the Plio-Pleistocene 13C cycle in the 405 kyr periodicity by
isotopic signatures of geological sources
Abstract: Closing the Plio-Pleistocene 13C cycle in the 405 kyr periodicity by isotopic signatures of geological sources
Peter Köhler
Clim. Past, 21, 1043–1060, https://doi.org/10.5194/cp-21-1043-2025, 2025
Using a carbon cycle model, I show that the 405 kyr periodicity found in marine δ13C during the last 5 million years and the offset in atmospheric δ13CO2 between the Last Glacial Maximum and the Penultimate Glacial Maximum are probably related to each other. They can be explained by variations in the δ13C signature of weathered carbonate rock or of volcanically degassed CO2, which vary mainly with obliquity (41 kyr), suggesting that Northern Hemispheric land ice sheets are their ultimate drivers.
PubDate: Fri, 13 Jun 2025 22:43:50 +020
DOI: 10.5194/cp-21-1043-2025 2025
- Controls of aeolian and fluvial sediment influx to the northern Red Sea
over the last 220 000 years
Abstract: Controls of aeolian and fluvial sediment influx to the northern Red Sea over the last 220 000 years
Werner Ehrmann, Paul A. Wilson, Helge W. Arz, and Gerhard Schmiedl
Clim. Past, 21, 1025–1041, https://doi.org/10.5194/cp-21-1025-2025, 2025
We report palaeoclimate and sediment provenance records for the last 220 kyr from a sediment core from the northern Red Sea. They comprise high-resolution grain size, clay mineral, and geochemical data, together with Nd and Sr isotope data. The data sets document a strong temporal variability in dust influx on glacial–interglacial timescales and several shorter-term strong fluvial episodes. A key finding is that the Nile delta became a major dust source during glacioeustatic sea-level lowstands.
PubDate: Fri, 13 Jun 2025 22:43:50 +020
DOI: 10.5194/cp-21-1025-2025 2025
- Global biome changes over the last 21 000 years inferred from
model–data comparisons
Abstract: Global biome changes over the last 21 000 years inferred from model–data comparisons
Chenzhi Li, Anne Dallmeyer, Jian Ni, Manuel Chevalier, Matteo Willeit, Andrei A. Andreev, Xianyong Cao, Laura Schild, Birgit Heim, Mareike Wieczorek, and Ulrike Herzschuh
Clim. Past, 21, 1001–1024, https://doi.org/10.5194/cp-21-1001-2025, 2025
We present global megabiome dynamics and distributions derived from pollen-based reconstructions over the last 21 000 years, which are suitable for the evaluation of Earth-system-model-based paleo-megabiome simulations. We identified strong deviations between pollen- and model-derived megabiome distributions in the circum-Arctic and Tibetan Plateau areas during the Last Glacial Maximum and early deglaciation and in northern Africa and the Mediterranean region during the Holocene.
PubDate: Wed, 11 Jun 2025 22:43:50 +020
DOI: 10.5194/cp-21-1001-2025 2025
- Mean ocean temperature change and decomposition of the benthic δ18O
record over the past 4.5 million years
Abstract: Mean ocean temperature change and decomposition of the benthic δ18O record over the past 4.5 million years
Peter U. Clark, Jeremy D. Shakun, Yair Rosenthal, Chenyu Zhu, Patrick J. Bartlein, Jonathan M. Gregory, Peter Köhler, Zhengyu Liu, and Daniel P. Schrag
Clim. Past, 21, 973–1000, https://doi.org/10.5194/cp-21-973-2025, 2025
We reconstruct changes in mean ocean temperature (ΔMOT) over the last 4.5 Myr. We find that the ratio of ΔMOT to changes in global mean sea surface temperature was around 0.5 before the Middle Pleistocene transition but was 1 thereafter. We subtract our ΔMOT reconstruction from the global δ18O record to derive the δ18O of seawater. Finally, we develop a theoretical understanding of why the ratio of ΔMOT / ΔGMSST changed over the Plio-Pleistocene.
PubDate: Tue, 03 Jun 2025 14:15:50 +020
DOI: 10.5194/cp-21-973-2025 2025
- Impact of deoxygenation and hydrological changes on the Black Sea nitrogen
cycle during the Last Deglaciation and Holocene
Abstract: Impact of deoxygenation and hydrological changes on the Black Sea nitrogen cycle during the Last Deglaciation and Holocene
Anna Cutmore, Nicole Bale, Rick Hennekam, Bingjie Yang, Darci Rush, Gert-Jan Reichart, Ellen C. Hopmans, and Stefan Schouten
Clim. Past, 21, 957–971, https://doi.org/10.5194/cp-21-957-2025, 2025
As human activities lower marine oxygen levels, understanding the impact on the marine nitrogen cycle is vital. The Black Sea, which became oxygen-deprived 9600 years ago, offers key insights. By studying organic compounds linked to nitrogen cycle processes, we found that, 7200 years ago, the Black Sea's nitrogen cycle significantly altered due to severe deoxygenation. This suggests that continued marine oxygen decline could similarly alter the marine nitrogen cycle, affecting vital ecosystems.
PubDate: Mon, 02 Jun 2025 14:15:50 +020
DOI: 10.5194/cp-21-957-2025 2025
- Magnetic properties and geochemistry of loess–paleosol sequences at the
Nowdeh section in northeastern Iran
Abstract: Magnetic properties and geochemistry of loess–paleosol sequences at the Nowdeh section in northeastern Iran
Vahid Feizi, Ghasem Azizi, Maryam Mollashahi, and Habib Alimohammadian
Clim. Past, 21, 941–955, https://doi.org/10.5194/cp-21-941-2025, 2025
This study explores past climate change in northeastern Iran by analysing the magnetic properties and geochemistry of loess (wind-blown dust) and paleosol (ancient soil) layers. Variations in these properties reveal shifts in temperature and rainfall patterns over time. The findings help reconstruct past environmental conditions and offer insights into how the region responded to climate variations, which can inform our understanding of future climate impacts.
PubDate: Wed, 28 May 2025 23:37:11 +020
DOI: 10.5194/cp-21-941-2025 2025
- The Early–Middle Pleistocene Transition in the Gulf of Cadiz (NE
Atlantic) – an interplay between subtropical gyre and extremely cold
surface waters
Abstract: The Early–Middle Pleistocene Transition in the Gulf of Cadiz (NE Atlantic) – an interplay between subtropical gyre and extremely cold surface waters
Aline Mega, Teresa Rodrigues, Emília Salgueiro, Mária Padilha, Henning Kuhnert, and Antje H. L. Voelker
Clim. Past, 21, 919–939, https://doi.org/10.5194/cp-21-919-2025, 2025
Our research explores climatic changes during the Early–Middle Pleistocene (1006–750 ka) on the southern Portuguese margin. We found that warm, subtropical-gyre-related conditions dominated. However, those conditions were occasionally interrupted by extreme cold events during the glacial periods. Our data show that these cold events, linked to changes in the North Atlantic's circulation, reached as far south as 36° N and significantly impacted marine ecosystems in the surface ocean.
PubDate: Tue, 20 May 2025 19:54:51 +020
DOI: 10.5194/cp-21-919-2025 2025
- Evaluating the 20th Century Reanalysis Version 3 with synoptic typing and
an East Antarctic ice core accumulation record
Abstract: Evaluating the 20th Century Reanalysis Version 3 with synoptic typing and an East Antarctic ice core accumulation record
Max T. Nilssen, Danielle G. Udy, and Tessa R. Vance
Clim. Past, 21, 897–917, https://doi.org/10.5194/cp-21-897-2025, 2025
Reanalyses can be used to study past weather and climate, but their reliability is uncertain in data-sparse regions, such as the southern Indian Ocean. We used weather typing and an ice core record from East Antarctica to show that the 20th Century Reanalysis project can better represent the weather conditions that lead to snowfall variability at the ice core site when key weather observations from the Southern Ocean (e.g. Macquarie Island) commence around the mid-20th century.
PubDate: Fri, 16 May 2025 13:02:17 +020
DOI: 10.5194/cp-21-897-2025 2025
- Thermal conditions on the coast of Labrador during the late 18th century
Abstract: Thermal conditions on the coast of Labrador during the late 18th century
Garima Singh, Rajmund Przybylak, Przemysław Wyszyński, Andrzej Araźny, and Konrad Chmist
Clim. Past, 21, 877–895, https://doi.org/10.5194/cp-21-877-2025, 2025
This study aims to determine the nature of the climate in Labrador in historical times (late 18th century), which is crucial to understanding past climate changes in the Arctic and their causes. It is equally important to estimate the range of natural climate variability, which can help in correctly recognizing the causes of present and future climate changes – especially the influence of humans on climate. The analysis shows a significant warming from historical to present times.
PubDate: Tue, 13 May 2025 15:57:42 +020
DOI: 10.5194/cp-21-877-2025 2025
- Subaqueous speleothems as archives of groundwater recharge on Australia's
southern arid margin
Abstract: Subaqueous speleothems as archives of groundwater recharge on Australia's southern arid margin
Calla N. Gould-Whaley, Russell N. Drysdale, Pauline C. Treble, Jan-Hendrik May, Stacey C. Priestley, John C. Hellstrom, Christopher R. Vardanega, and Clare C. Buswell
Clim. Past, 21, 857–876, https://doi.org/10.5194/cp-21-857-2025, 2025
Climate change is causing enhanced aridity across many regions of the globe, leading to increased reliance on groundwater resources. We need to understand how groundwater recharge behaves in arid regions over long timescales; unfortunately, arid landscapes tend to preserve very little evidence of their climatic past. We present evidence to suggest that carbonate formations that grow in groundwater can be used as archives of past groundwater recharge in Australia's arid zone.
PubDate: Wed, 07 May 2025 17:20:52 +020
DOI: 10.5194/cp-21-857-2025 2025
- Middle Miocene climate evolution in the northern Mediterranean region
(Digne–Valensole basin, SE France)
Abstract: Middle Miocene climate evolution in the northern Mediterranean region (Digne–Valensole basin, SE France)
Armelle Ballian, Maud J. M. Meijers, Isabelle Cojan, Damien Huyghe, Miguel Bernecker, Katharina Methner, Mattia Tagliavento, Jens Fiebig, and Andreas Mulch
Clim. Past, 21, 841–856, https://doi.org/10.5194/cp-21-841-2025, 2025
During the Middle Miocene, the Earth transitioned from a warm to a colder period, significantly impacting ecosystems and climate. We present a 23–13 Ma climate record of soil carbonates from a northern Mediterranean basin. We propose that rapid temperature shifts in our data result from changes in atmospheric circulation patterns. Our climate record aligns well with contemporaneous terrestrial European and global marine records, enhancing our understanding of Miocene climate dynamics.
PubDate: Tue, 22 Apr 2025 19:15:57 +020
DOI: 10.5194/cp-21-841-2025 2025
- Evidence for millennial-scale interactions between Hg cycling and
hydroclimate from Lake Bosumtwi, Ghana
Abstract: Evidence for millennial-scale interactions between Hg cycling and hydroclimate from Lake Bosumtwi, Ghana
Alice R. Paine, Joost Frieling, Timothy M. Shanahan, Tamsin A. Mather, Nicholas McKay, Stuart A. Robinson, David M. Pyle, Isabel M. Fendley, Ruth Kiely, and William D. Gosling
Clim. Past, 21, 817–839, https://doi.org/10.5194/cp-21-817-2025, 2025
Few tropical mercury (Hg) records extend beyond ~ 12 ka, meaning our current understanding of Hg behaviour may not fully account for the impact of long-term hydroclimate changes on the Hg cycle in these environments. Here, we present an ~ 96 kyr Hg record from Lake Bosumtwi, Ghana. A coupled response is observed between Hg flux and shifts in sediment composition reflective of changes in lake level, suggesting that hydroclimate may be a key driver of tropical Hg cycling over millennial timescales.
PubDate: Thu, 17 Apr 2025 17:43:11 +020
DOI: 10.5194/cp-21-817-2025 2025
- High-resolution Holocene record based on detailed tephrochronology from
Torfdalsvatn, north Iceland, reveals natural and anthropogenic impacts on
terrestrial and aquatic environments
Abstract: High-resolution Holocene record based on detailed tephrochronology from Torfdalsvatn, north Iceland, reveals natural and anthropogenic impacts on terrestrial and aquatic environments
David J. Harning, Christopher R. Florian, Áslaug Geirsdóttir, Thor Thordarson, Gifford H. Miller, Yarrow Axford, and Sædís Ólafsdóttir
Clim. Past, 21, 795–815, https://doi.org/10.5194/cp-21-795-2025, 2025
Questions remain about the past climate in Iceland, including the relative impacts of natural and human factors on vegetation change and soil erosion. We present a sub-centennial-scale record of landscape and algal productivity from a lake in north Iceland. Along with a high-resolution tephra age constraint that covers the last ∼ 12 000 years, our record provides an environmental template for the region and novel insight into the sensitivity of the Icelandic ecosystem to natural and human impacts.
PubDate: Fri, 11 Apr 2025 20:43:04 +020
DOI: 10.5194/cp-21-795-2025 2025
- Pattern scaling of simulated vegetation change in northern Africa during
glacial cycles
Abstract: Pattern scaling of simulated vegetation change in northern Africa during glacial cycles
Mateo Duque-Villegas, Martin Claussen, Thomas Kleinen, Jürgen Bader, and Christian H. Reick
Clim. Past, 21, 773–794, https://doi.org/10.5194/cp-21-773-2025, 2025
We simulate the last glacial cycle with a comprehensive model of the Earth system and investigate vegetation cover change in northern Africa during the last four African Humid Periods (AHPs). We find a common pattern of vegetation change and relate it with climatic factors in order to discuss how vegetation might have evolved during even older AHPs. This scaling relationship we find according to past AHPs fails to account for projected changes in northern Africa under strong greenhouse gas warming.
PubDate: Thu, 10 Apr 2025 20:43:04 +020
DOI: 10.5194/cp-21-773-2025 2025
- Environmental controls of rapid terrestrial organic matter mobilization to
the western Laptev Sea since the Last Deglaciation
Abstract: Environmental controls of rapid terrestrial organic matter mobilization to the western Laptev Sea since the Last Deglaciation
Tsai-Wen Lin, Tommaso Tesi, Jens Hefter, Hendrik Grotheer, Jutta Wollenburg, Florian Adolphi, Henning A. Bauch, Alessio Nogarotto, Juliane Müller, and Gesine Mollenhauer
Clim. Past, 21, 753–772, https://doi.org/10.5194/cp-21-753-2025, 2025
In order to understand the mechanisms governing permafrost organic matter remobilization, we investigated organic matter composition during past intervals of rapid sea-level rise, of inland warming, and of dense sea-ice cover in the Laptev Sea. We find that sea-level rise resulted in widespread erosion and transport of permafrost materials to the ocean but that erosion is mitigated by regional dense sea-ice cover. Factors like inland warming or floods increase permafrost mobilization locally.
PubDate: Fri, 04 Apr 2025 15:34:06 +020
DOI: 10.5194/cp-21-753-2025 2025
- Deglaciation and abrupt events in a coupled comprehensive
atmosphere–ocean–ice-sheet–solid-earth model
Abstract: Deglaciation and abrupt events in a coupled comprehensive atmosphere–ocean–ice-sheet–solid-earth model
Uwe Mikolajewicz, Marie-Luise Kapsch, Clemens Schannwell, Katharina D. Six, Florian A. Ziemen, Meike Bagge, Jean-Philippe Baudouin, Olga Erokhina, Veronika Gayler, Volker Klemann, Virna L. Meccia, Anne Mouchet, and Thomas Riddick
Clim. Past, 21, 719–751, https://doi.org/10.5194/cp-21-719-2025, 2025
A fully coupled atmosphere–ocean–ice-sheet–solid-earth model was applied to simulate the time from the Last Glacial Maximum (about 25 000 years before the present) to the pre-industrial period. The model simulations are compared to observational estimates. During this climate transition, the model simulates several abrupt changes in the North Atlantic region, which are initiated by different processes. The underlying mechanisms are analysed and described.
PubDate: Wed, 02 Apr 2025 12:51:33 +020
DOI: 10.5194/cp-21-719-2025 2025
- A question of time and space: a model approach to the synchronous
precipitation of gypsum and halite during the Messinian Salinity Crisis
Abstract: A question of time and space: a model approach to the synchronous precipitation of gypsum and halite during the Messinian Salinity Crisis
Ronja M. Ebner and Paul T. Meijer
Clim. Past, 21, 705–718, https://doi.org/10.5194/cp-21-705-2025, 2025
This work explores the spatial distribution of halite and gypsum within salt giants that formed in semi-enclosed basins via numerical box models. The results are compared to the Messinian salt giant, while our description of restrictions makes them transferable to other basins. As such, we propose a general timeline for precipitation patterns. Our results indicate that it is unlikely for gypsum and halite to precipitate simultaneously without additional internal restriction.
PubDate: Tue, 01 Apr 2025 12:51:33 +020
DOI: 10.5194/cp-21-705-2025 2025
- Contrasts in the marine inorganic carbon chemistry of the Benguela
Upwelling System since the Last Glacial Maximum
Abstract: Contrasts in the marine inorganic carbon chemistry of the Benguela Upwelling System since the Last Glacial Maximum
Szabina Karancz, Lennart J. de Nooijer, Bas van der Wagt, Marcel T. J. van der Meer, Sambuddha Misra, Rick Hennekam, Zeynep Erdem, Julie Lattaud, Negar Haghipour, Stefan Schouten, and Gert-Jan Reichart
Clim. Past, 21, 679–704, https://doi.org/10.5194/cp-21-679-2025, 2025
Changes in upwelling intensity of the Benguela upwelling region during the last glacial motivated us to investigate the local CO2 history during the last glacial-to-interglacial transition. Using various geochemical tracers on archives from both subsurface and surface waters reveals enhanced storage of carbon at depth during the Last Glacial Maximum. An efficient biological pump likely prevented outgassing of CO2 from intermediate depth to the atmosphere.
PubDate: Tue, 25 Mar 2025 19:36:45 +010
DOI: 10.5194/cp-21-679-2025 2025
- Reconstruction of Holocene and Last Interglacial vegetation dynamics and
wildfire activity in southern Siberia
Abstract: Reconstruction of Holocene and Last Interglacial vegetation dynamics and wildfire activity in southern Siberia
Jade Margerum, Julia Homann, Stuart Umbo, Gernot Nehrke, Thorsten Hoffmann, Anton Vaks, Aleksandr Kononov, Alexander Osintsev, Alena Giesche, Andrew Mason, Franziska A. Lechleitner, Gideon M. Henderson, Ola Kwiecien, and Sebastian F. M. Breitenbach
Clim. Past, 21, 661–677, https://doi.org/10.5194/cp-21-661-2025, 2025
We analyse a southern Siberian stalagmite to reconstruct soil respiration, wildfire, and vegetation trends during the Last Interglacial (LIG) (124.1–118.8 ka) and the Holocene (10–0 ka). Wildfires were more prevalent during the LIG than the Holocene and were supported by fire-prone species, low soil respiration, and a greater difference between summer and winter temperature. We show that vegetation type and summer/winter temperature contrast are strong drivers of Siberian wildfires.
PubDate: Thu, 20 Mar 2025 13:11:31 +010
DOI: 10.5194/cp-21-661-2025 2025
- Patterns of changing surface climate variability from the Last Glacial
Maximum to present in transient model simulations
Abstract: Patterns of changing surface climate variability from the Last Glacial Maximum to present in transient model simulations
Elisa Ziegler, Nils Weitzel, Jean-Philippe Baudouin, Marie-Luise Kapsch, Uwe Mikolajewicz, Lauren Gregoire, Ruza Ivanovic, Paul J. Valdes, Christian Wirths, and Kira Rehfeld
Clim. Past, 21, 627–659, https://doi.org/10.5194/cp-21-627-2025, 2025
During the Last Deglaciation, global surface temperature rose by about 4–7 °C over several millennia. We show that changes in year-to-year up to century-to-century fluctuations of temperature and precipitation during the Deglaciation were mostly larger than during either the preceding or succeeding more stable periods in 15 climate model simulations. The analysis demonstrates how ice sheets, meltwater, and volcanism influence simulated variability to inform future simulation protocols.
PubDate: Tue, 11 Mar 2025 21:37:53 +010
DOI: 10.5194/cp-21-627-2025 2025
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