Articles | Volume 12, issue 12
https://doi.org/10.5194/cp-12-2255-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
https://doi.org/10.5194/cp-12-2255-2016
© Author(s) 2016. This work is distributed under
the Creative Commons Attribution 3.0 License.
the Creative Commons Attribution 3.0 License.
Research article
| 
21 Dec 2016
Research article |
| 21 Dec 2016
Assessing performance and seasonal bias of pollen-based climate reconstructions in a perfect model world
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
present address: British Antarctic Survey, Cambridge, UK
Mathias Trachsel
CORRESPONDING AUTHOR
Department of Biology, University of Bergen, Postboks 7803, 5020 Bergen, Norway
present address: Department of Geology, University of Maryland, College Park, MD, USA
Richard J. Telford
Department of Biology, University of Bergen, Postboks 7803, 5020 Bergen, Norway
Bjerknes Center for Climate Research, Allégaten 55, 5007 Bergen, Norway
Thomas Laepple
Alfred Wegener Institute, Helmholtz Centre for Polar and Marine Research, 14473 Potsdam, Germany
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Antoine Grisart, Mathieu Casado, Vasileios Gkinis, Bo Vinther, Philippe Naveau, Mathieu Vrac, Thomas Laepple, Bénédicte Minster, Frederic Prié, Barbara Stenni, Elise Fourré, Hans Christian Steen-Larsen, Jean Jouzel, Martin Werner, Katy Pol, Valérie Masson-Delmotte, Maria Hoerhold, Trevor Popp, and Amaelle Landais
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Janica C. Bühler, Josefine Axelsson, Franziska A. Lechleitner, Jens Fohlmeister, Allegra N. LeGrande, Madhavan Midhun, Jesper Sjolte, Martin Werner, Kei Yoshimura, and Kira Rehfeld
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target site for the temperature reconstruction, and a second one optimally lies more than 500 km away.
Raphaël Hébert, Kira Rehfeld, and Thomas Laepple
Nonlin. Processes Geophys., 28, 311–328, https://doi.org/10.5194/npg-28-311-2021, https://doi.org/10.5194/npg-28-311-2021, 2021
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Paleoclimate proxy data are essential for broadening our understanding of climate variability. There remain, however, challenges for traditional methods of variability analysis to be applied to such data, which are usually irregular. We perform a comparative analysis of different methods of scaling analysis, which provide variability estimates as a function of timescales, applied to irregular paleoclimate proxy data.
Elisa Ziegler and Kira Rehfeld
Geosci. Model Dev., 14, 2843–2866, https://doi.org/10.5194/gmd-14-2843-2021, https://doi.org/10.5194/gmd-14-2843-2021, 2021
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Past climate changes are the only record of how the climate responds to changes in conditions on Earth, but simulations with complex climate models are challenging. We extended a simple climate model such that it simulates the development of temperatures over time. In the model, changes in carbon dioxide and ice distribution affect the simulated temperatures the most. The model is very efficient and can therefore be used to examine past climate changes happening over long periods of time.
Janica C. Bühler, Carla Roesch, Moritz Kirschner, Louise Sime, Max D. Holloway, and Kira Rehfeld
Clim. Past, 17, 985–1004, https://doi.org/10.5194/cp-17-985-2021, https://doi.org/10.5194/cp-17-985-2021, 2021
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We present three new isotope-enabled simulations for the last millennium (850–1850 CE) and compare them to records from a global speleothem database. Offsets between the simulated and measured oxygen isotope ratios are fairly small. While modeled oxygen isotope ratios are more variable on decadal timescales, proxy records are more variable on (multi-)centennial timescales. This could be due to a lack of long-term variability in complex model simulations, but proxy biases cannot be excluded.
Andrew M. Dolman, Torben Kunz, Jeroen Groeneveld, and Thomas Laepple
Clim. Past, 17, 825–841, https://doi.org/10.5194/cp-17-825-2021, https://doi.org/10.5194/cp-17-825-2021, 2021
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Uncertainties in climate proxy records are temporally autocorrelated. By deriving expressions for the power spectra of errors in proxy records, we can estimate appropriate uncertainties for any timescale, for example, for temporally smoothed records or for time slices. Here we outline and demonstrate this approach for climate proxies recovered from marine sediment cores.
Laia Comas-Bru, Kira Rehfeld, Carla Roesch, Sahar Amirnezhad-Mozhdehi, Sandy P. Harrison, Kamolphat Atsawawaranunt, Syed Masood Ahmad, Yassine Ait Brahim, Andy Baker, Matthew Bosomworth, Sebastian F. M. Breitenbach, Yuval Burstyn, Andrea Columbu, Michael Deininger, Attila Demény, Bronwyn Dixon, Jens Fohlmeister, István Gábor Hatvani, Jun Hu, Nikita Kaushal, Zoltán Kern, Inga Labuhn, Franziska A. Lechleitner, Andrew Lorrey, Belen Martrat, Valdir Felipe Novello, Jessica Oster, Carlos Pérez-Mejías, Denis Scholz, Nick Scroxton, Nitesh Sinha, Brittany Marie Ward, Sophie Warken, Haiwei Zhang, and SISAL Working Group members
Earth Syst. Sci. Data, 12, 2579–2606, https://doi.org/10.5194/essd-12-2579-2020, https://doi.org/10.5194/essd-12-2579-2020, 2020
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This paper presents an updated version of the SISAL (Speleothem Isotope Synthesis and Analysis) database. This new version contains isotopic data from 691 speleothem records from 294 cave sites and new age–depth models, including their uncertainties, for 512 speleothems.
Mathieu Casado, Thomas Münch, and Thomas Laepple
Clim. Past, 16, 1581–1598, https://doi.org/10.5194/cp-16-1581-2020, https://doi.org/10.5194/cp-16-1581-2020, 2020
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The isotopic composition in ice cores from Antarctica is usually interpreted as a temperature proxy. Using a forward model, we show how different the signal in ice cores and the actual climatic signal are. Precipitation intermittency and diffusion do indeed affect the archived signal, leading to the reshuffling of the signal which limits the ability to reconstruct high-resolution climatic variations with ice cores.
Torben Kunz, Andrew M. Dolman, and Thomas Laepple
Clim. Past, 16, 1469–1492, https://doi.org/10.5194/cp-16-1469-2020, https://doi.org/10.5194/cp-16-1469-2020, 2020
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This paper introduces a method to estimate the uncertainty of climate reconstructions from single sediment proxy records. The method can compute uncertainties as a function of averaging timescale, thereby accounting for the fact that some components of the uncertainty are autocorrelated in time. This is achieved by treating the problem in the spectral domain. Fully analytic expressions are derived. A companion paper (Part 2) complements this with application-oriented examples of the method.
Kira Rehfeld, Raphaël Hébert, Juan M. Lora, Marcus Lofverstrom, and Chris M. Brierley
Earth Syst. Dynam., 11, 447–468, https://doi.org/10.5194/esd-11-447-2020, https://doi.org/10.5194/esd-11-447-2020, 2020
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Under continued anthropogenic greenhouse gas emissions, it is likely that global mean surface temperature will continue to increase. Little is known about changes in climate variability. We analyze surface climate variability and compare it to mean change in colder- and warmer-than-present climate model simulations. In most locations, but not on subtropical land, simulated temperature variability up to decadal timescales decreases with mean temperature, and precipitation variability increases.
Laia Comas-Bru, Sandy P. Harrison, Martin Werner, Kira Rehfeld, Nick Scroxton, Cristina Veiga-Pires, and SISAL working group members
Clim. Past, 15, 1557–1579, https://doi.org/10.5194/cp-15-1557-2019, https://doi.org/10.5194/cp-15-1557-2019, 2019
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We use an updated version of the Speleothem Isotopes Synthesis and Analysis (SISAL) database and palaeoclimate simulations generated using the ECHAM5-wiso isotope-enabled climate model to provide a protocol for using speleothem isotopic data for model evaluation, including screening the observations and the optimum period for the modern observational baseline. We also illustrate techniques through which the absolute isotopic values during any time period could be used for model evaluation.
Maria Reschke, Kira Rehfeld, and Thomas Laepple
Clim. Past, 15, 521–537, https://doi.org/10.5194/cp-15-521-2019, https://doi.org/10.5194/cp-15-521-2019, 2019
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We empirically estimate signal-to-noise ratios of temperature proxy records used in global compilations of the middle to late Holocene by comparing the spatial correlation structure of proxy records and climate model simulations accounting for noise and time uncertainty. We find that low signal contents of the proxy records or, alternatively, more localised climate variations recorded by proxies than suggested by current model simulations suggest caution when interpreting multi-proxy datasets.
Matthias M. May and Kira Rehfeld
Earth Syst. Dynam., 10, 1–7, https://doi.org/10.5194/esd-10-1-2019, https://doi.org/10.5194/esd-10-1-2019, 2019
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Current CO2 emission rates are incompatible with the 2 °C target for global warming. Negative emission technologies are therefore an important basis for climate policy scenarios. We show that photoelectrochemical CO2 reduction might be a viable, high-efficiency alternative to biomass-based approaches, which reduce competition for arable land. To develop them, chemical reactions have to be optimized for CO2 removal, which deviates from energetic efficiency optimization in solar fuel applications.
Thomas Münch and Thomas Laepple
Clim. Past, 14, 2053–2070, https://doi.org/10.5194/cp-14-2053-2018, https://doi.org/10.5194/cp-14-2053-2018, 2018
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Proxy data on climate variations contain noise from many sources and, for reliable estimates, we need to determine those temporal scales at which the climate signal in the proxy record dominates the noise. We developed a method to derive timescale-dependent estimates of temperature proxy signal-to-noise ratios, which we apply and discuss in the context of Antarctic ice-core records but which in general are applicable to a large set of palaeoclimate records.
Nadia Al-Sabouni, Isabel S. Fenton, Richard J. Telford, and Michal Kučera
J. Micropalaeontol., 37, 519–534, https://doi.org/10.5194/jm-37-519-2018, https://doi.org/10.5194/jm-37-519-2018, 2018
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In this study we investigate consistency in species-level identifications and whether disagreements are predictable. Overall, 21 researchers from across the globe identified sets of 300 specimens or digital images of planktonic foraminifera. Digital identifications tended to be more disparate. Participants trained by the same person often had more similar identifications. Disagreements hardly affected transfer-function temperature estimates but produced larger differences in diversity metrics.
Andrew M. Dolman and Thomas Laepple
Clim. Past, 14, 1851–1868, https://doi.org/10.5194/cp-14-1851-2018, https://doi.org/10.5194/cp-14-1851-2018, 2018
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Climate proxies from marine sediments provide an important record of past temperatures, but contain noise from many sources. These include mixing by burrowing organisms, seasonal and habitat biases, measurement error, and small sample size effects. We have created a forward model that simulates the creation of proxy records and provides it as a user-friendly R package. It allows multiple sources of uncertainty to be considered together when interpreting proxy climate records.
Mathieu Casado, Amaelle Landais, Ghislain Picard, Thomas Münch, Thomas Laepple, Barbara Stenni, Giuliano Dreossi, Alexey Ekaykin, Laurent Arnaud, Christophe Genthon, Alexandra Touzeau, Valerie Masson-Delmotte, and Jean Jouzel
The Cryosphere, 12, 1745–1766, https://doi.org/10.5194/tc-12-1745-2018, https://doi.org/10.5194/tc-12-1745-2018, 2018
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Ice core isotopic records rely on the knowledge of the processes involved in the archival processes of the snow. In the East Antarctic Plateau, post-deposition processes strongly affect the signal found in the surface and buried snow compared to the initial climatic signal. We evaluate the different contributions to the surface snow isotopic composition between the precipitation and the exchanges with the atmosphere and the variability of the isotopic signal found in profiles from snow pits.
Thomas Laepple, Thomas Münch, Mathieu Casado, Maria Hoerhold, Amaelle Landais, and Sepp Kipfstuhl
The Cryosphere, 12, 169–187, https://doi.org/10.5194/tc-12-169-2018, https://doi.org/10.5194/tc-12-169-2018, 2018
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We explain why snow pits across different sites in East Antarctica show visually similar isotopic variations. We argue that the similarity and the apparent cycles of around 20 cm in the δD and δ18O variations are the result of a seasonal cycle in isotopes, noise, for example from precipitation intermittency, and diffusion. The near constancy of the diffusion length across many ice-coring sites explains why the structure and cycle length is largely independent of the accumulation conditions.
Thomas Münch, Sepp Kipfstuhl, Johannes Freitag, Hanno Meyer, and Thomas Laepple
The Cryosphere, 11, 2175–2188, https://doi.org/10.5194/tc-11-2175-2017, https://doi.org/10.5194/tc-11-2175-2017, 2017
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The importance of post-depositional changes for the temperature interpretation of water isotopes is poorly constrained by observations. Here, for the first time, temporal isotope changes in the open-porous firn are directly analysed using a large array of shallow isotope profiles. By this, we can reject the possibility of post-depositional change beyond diffusion and densification as the cause of the discrepancy between isotope and local temperature variations at Kohnen Station, East Antarctica.
Mathieu Casado, Amaelle Landais, Ghislain Picard, Thomas Münch, Thomas Laepple, Barbara Stenni, Giuliano Dreossi, Alexey Ekaykin, Laurent Arnaud, Christophe Genthon, Alexandra Touzeau, Valérie Masson-Delmotte, and Jean Jouzel
The Cryosphere Discuss., https://doi.org/10.5194/tc-2016-263, https://doi.org/10.5194/tc-2016-263, 2016
Revised manuscript not accepted
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Ice core isotopic records rely on the knowledge of the processes involved in the archival of the snow. In the East Antarctic Plateau, post-deposition processes strongly affect the signal found in the surface and buried snow compared to the initial climatic signal. We evaluate the different contributions to the surface snow isotopic composition between the precipitation and the exchanges with the atmosphere and the variability of the isotopic signal found in profiles from snow pits.
Thomas Münch, Sepp Kipfstuhl, Johannes Freitag, Hanno Meyer, and Thomas Laepple
Clim. Past, 12, 1565–1581, https://doi.org/10.5194/cp-12-1565-2016, https://doi.org/10.5194/cp-12-1565-2016, 2016
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Ice-core oxygen isotope ratios are a key climate archive to infer past temperatures, an interpretation however complicated by non-climatic noise. Based on 50 m firn trenches, we present for the first time a two-dimensional view (vertical × horizontal) of how oxygen isotopes are stored in Antarctic firn. A statistical noise model allows inferences for the validity of ice coring efforts to reconstruct past temperatures, highlighting the need of replicate cores for Holocene climate reconstructions.
Mathias Trachsel and Richard J. Telford
Clim. Past, 12, 1215–1223, https://doi.org/10.5194/cp-12-1215-2016, https://doi.org/10.5194/cp-12-1215-2016, 2016
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In spatially structured environments, conventional cross validation results in over-optimistic transfer function performance estimates. H-block cross validation, where all samples within h kilometres of the test samples are omitted is a method for obtaining unbiased transfer function performance estimates. We assess three methods for determining the optimal h using simulated data and published transfer functions. Some transfer functions perform notably worse when h-block cross validation is used.
M. Trachsel and A. Nesje
The Cryosphere, 9, 1401–1414, https://doi.org/10.5194/tc-9-1401-2015, https://doi.org/10.5194/tc-9-1401-2015, 2015
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We employ statistical models to model annual glacier mass balances of eight Scandinavian glaciers as function of summer temperature and winter precipitation.
Relative importances of winter precipitation and summer temperature vary in time.
Relative importances are influenced by AMO and NAO.
K. Rehfeld, N. Molkenthin, and J. Kurths
Nonlin. Processes Geophys., 21, 691–703, https://doi.org/10.5194/npg-21-691-2014, https://doi.org/10.5194/npg-21-691-2014, 2014
L. Tupikina, K. Rehfeld, N. Molkenthin, V. Stolbova, N. Marwan, and J. Kurths
Nonlin. Processes Geophys., 21, 705–711, https://doi.org/10.5194/npg-21-705-2014, https://doi.org/10.5194/npg-21-705-2014, 2014
N. Molkenthin, K. Rehfeld, V. Stolbova, L. Tupikina, and J. Kurths
Nonlin. Processes Geophys., 21, 651–657, https://doi.org/10.5194/npg-21-651-2014, https://doi.org/10.5194/npg-21-651-2014, 2014
K. Rehfeld and J. Kurths
Clim. Past, 10, 107–122, https://doi.org/10.5194/cp-10-107-2014, https://doi.org/10.5194/cp-10-107-2014, 2014
R. J. Telford, C. Li, and M. Kucera
Clim. Past, 9, 859–870, https://doi.org/10.5194/cp-9-859-2013, https://doi.org/10.5194/cp-9-859-2013, 2013
Related subject area
Subject: Proxy Use-Development-Validation | Archive: Terrestrial Archives | Timescale: Holocene
High-resolution Holocene record based on detailed tephrochronology from Torfdalsvatn, north Iceland, reveals natural and anthropogenic impacts on terrestrial and aquatic environments
Multi-century mean summer temperature variations in the Southern Rhaetian Alps reconstructed from Larix decidua blue intensity data
SCUBIDO: a Bayesian modelling approach to reconstruct palaeoclimate from multivariate lake sediment data
A continental reconstruction of hydroclimatic variability in South America during the past 2000 years
A Holocene history of climate, fire, landscape evolution, and human activity in northeastern Iceland
A global compilation of diatom silica oxygen isotope records from lake sediment – trends and implications for climate reconstruction
BrGDGT-based seasonal paleotemperature reconstruction for the last 15 000 years from a shallow lake on the eastern Tibetan Plateau
Reconstructing 15 000 years of southern France temperatures from coupled pollen and molecular (branched glycerol dialkyl glycerol tetraether) markers (Canroute, Massif Central)
Pollen-based reconstructions of Holocene climate trends in the eastern Mediterranean region
Spatiotemporal Intertropical Convergence Zone dynamics during the last 3 millennia in northeastern Brazil and related impacts in modern human history
Holocene climates of the Iberian Peninsula: pollen-based reconstructions of changes in the west–east gradient of temperature and moisture
Holocene climate and oceanography of the coastal Western United States and California Current System
Reconstructing Holocene temperatures in time and space using paleoclimate data assimilation
Long-term trends in diatom diversity and palaeoproductivity: a 16 000-year multidecadal record from Lake Baikal, southern Siberia
A 406-year non-growing-season precipitation reconstruction in the southeastern Tibetan Plateau
Climatic variations during the Holocene inferred from radiocarbon and stable carbon isotopes in speleothems from a high-alpine cave
Winter–spring warming in the North Atlantic during the last 2000 years: evidence from southwest Iceland
Climate reconstructions based on GDGT and pollen surface datasets from Mongolia and Baikal area: calibrations and applicability to extremely cold–dry environments over the Late Holocene
Sampling density and date along with species selection influence spatial representation of tree-ring reconstructions
Changes in high-intensity precipitation on the northern Apennines (Italy) as revealed by multidisciplinary data over the last 9000 years
Neoglacial trends in diatom dynamics from a small alpine lake in the Qinling mountains of central China
Centennial- to millennial-scale monsoon changes since the last deglaciation linked to solar activities and North Atlantic cooling
Algal lipids reveal unprecedented warming rates in alpine areas of SW Europe during the industrial period
Reconstructing seasonality through stable-isotope and trace-element analyses of the Proserpine stalagmite, Han-sur-Lesse cave, Belgium: indications for climate-driven changes during the last 400 years
Two millennia of Main region (southern Germany) hydroclimate variability
Combining a pollen and macrofossil synthesis with climate simulations for spatial reconstructions of European climate using Bayesian filtering
Lignin oxidation products as a potential proxy for vegetation and environmental changes in speleothems and cave drip water – a first record from the Herbstlabyrinth, central Germany
How dry was the Younger Dryas? Evidence from a coupled δ2H–δ18O biomarker paleohygrometer applied to the Gemündener Maar sediments, Western Eifel, Germany
Siberian tree-ring and stable isotope proxies as indicators of temperature and moisture changes after major stratospheric volcanic eruptions
The 4.2 ka BP Event in the Mediterranean region: an overview
Technical note: Optimizing the utility of combined GPR, OSL, and Lidar (GOaL) to extract paleoenvironmental records and decipher shoreline evolution
The onset of neoglaciation in Iceland and the 4.2 ka event
Hydroclimatic variations in southeastern China during the 4.2 ka event reflected by stalagmite records
Fire, vegetation, and Holocene climate in a southeastern Tibetan lake: a multi-biomarker reconstruction from Paru Co
Climate impact on the development of Pre-Classic Maya civilisation
Synchronizing 10Be in two varved lake sediment records to IntCal13 14C during three grand solar minima
Technical note: Open-paleo-data implementation pilot – the PAGES 2k special issue
A chironomid-based record of temperature variability during the past 4000 years in northern China and its possible societal implications
Insights into Atlantic multidecadal variability using the Last Millennium Reanalysis framework
Three distinct Holocene intervals of stalagmite deposition and nondeposition revealed in NW Madagascar, and their paleoclimate implications
Examining bias in pollen-based quantitative climate reconstructions induced by human impact on vegetation in China
A dual-biomarker approach for quantification of changes in relative humidity from sedimentary lipid D∕H ratios
Pseudo-proxy tests of the analogue method to reconstruct spatially resolved global temperature during the Common Era
Development and evaluation of a system of proxy data assimilation for paleoclimate reconstruction
A chironomid-based mean July temperature inference model from the south-east margin of the Tibetan Plateau, China
Quantitative reconstruction of summer precipitation using a mid-Holocene δ13C common millet record from Guanzhong Basin, northern China
North Atlantic Oscillation controls on oxygen and hydrogen isotope gradients in winter precipitation across Europe; implications for palaeoclimate studies
A 368-year maximum temperature reconstruction based on tree-ring data in the northwestern Sichuan Plateau (NWSP), China
Inferring late-Holocene climate in the Ecuadorian Andes using a chironomid-based temperature inference model
A high-altitude peatland record of environmental changes in the NW Argentine Andes (24 ° S) over the last 2100 years
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, https://doi.org/10.5194/cp-21-795-2025, 2025
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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.
Riccardo Cerrato, Maria Cristina Salvatore, Michele Brunetti, Andrea Somma, and Carlo Baroni
Clim. Past, 21, 609–626, https://doi.org/10.5194/cp-21-609-2025, https://doi.org/10.5194/cp-21-609-2025, 2025
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Understanding past climates requires data extending beyond modern instrumental records. This study shows that blue intensity (BI) measurements from European larch trees in the Southern Rhaetian Alps provide a stronger proxy for reconstructing past summer temperatures than traditional tree-ring-width data. BI processing enables regional-scale reconstructions and helps extend these reconstructions to the Mediterranean Basin and northern Europe, with excellent correlations to existing data.
Laura Boyall, Andrew C. Parnell, Paul Lincoln, Antti Ojala, Armand Hernández, and Celia Martin-Puertas
Clim. Past Discuss., https://doi.org/10.5194/cp-2024-82, https://doi.org/10.5194/cp-2024-82, 2024
Revised manuscript accepted for CP
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We present a new approach to reconstructing annual mean temperature using geochemical data from lake sediments. This paper uses Bayesian inference, a type of statistical approach, and creates a model called SCUBIDO which takes the high-resolution geochemical data and transforms this into quantitative climate information at an annual resolution. We show the results from two lakes from England and Finland to produce temperature reconstructions for the past 8000 years with data every year.
Mathurin A. Choblet, Janica C. Bühler, Valdir F. Novello, Nathan J. Steiger, and Kira Rehfeld
Clim. Past, 20, 2117–2141, https://doi.org/10.5194/cp-20-2117-2024, https://doi.org/10.5194/cp-20-2117-2024, 2024
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Past climate reconstructions are essential for understanding climate mechanisms and drivers. Our focus is on the South American continent over the past 2000 years. We offer a new reconstruction that particularly utilizes data from speleothems, previously absent from continent-wide reconstructions. We use paleoclimate data assimilation, a reconstruction method that combines information from climate archives and climate simulations.
Nicolò Ardenghi, David J. Harning, Jonathan H. Raberg, Brooke R. Holman, Thorvaldur Thordarson, Áslaug Geirsdóttir, Gifford H. Miller, and Julio Sepúlveda
Clim. Past, 20, 1087–1123, https://doi.org/10.5194/cp-20-1087-2024, https://doi.org/10.5194/cp-20-1087-2024, 2024
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Analysing a sediment record from Stóra Viðarvatn (NE Iceland), we reveal how natural factors and human activities influenced environmental changes (erosion, wildfires) over the last 11 000 years. We found increased fire activity around 3000 and 1500 years ago, predating human settlement, likely driven by natural factors like precipitation shifts. Declining summer temperatures increased erosion vulnerability, exacerbated by farming and animal husbandry, which in turn may have reduced wildfires.
Philip Meister, Anne Alexandre, Hannah Bailey, Philip Barker, Boris K. Biskaborn, Ellie Broadman, Rosine Cartier, Bernhard Chapligin, Martine Couapel, Jonathan R. Dean, Bernhard Diekmann, Poppy Harding, Andrew C. G. Henderson, Armand Hernandez, Ulrike Herzschuh, Svetlana S. Kostrova, Jack Lacey, Melanie J. Leng, Andreas Lücke, Anson W. Mackay, Eniko Katalin Magyari, Biljana Narancic, Cécile Porchier, Gunhild Rosqvist, Aldo Shemesh, Corinne Sonzogni, George E. A. Swann, Florence Sylvestre, and Hanno Meyer
Clim. Past, 20, 363–392, https://doi.org/10.5194/cp-20-363-2024, https://doi.org/10.5194/cp-20-363-2024, 2024
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This paper presents the first comprehensive compilation of diatom oxygen isotope records in lake sediments (δ18OBSi), supported by lake basin parameters. We infer the spatial and temporal coverage of δ18OBSi records and discuss common hemispheric trends on centennial and millennial timescales. Key results are common patterns for hydrologically open lakes in Northern Hemisphere extratropical regions during the Holocene corresponding to known climatic epochs, i.e. the Holocene Thermal Maximum.
Xiaohuan Hou, Nannan Wang, Zhe Sun, Kan Yuan, Xianyong Cao, and Juzhi Hou
Clim. Past, 20, 335–348, https://doi.org/10.5194/cp-20-335-2024, https://doi.org/10.5194/cp-20-335-2024, 2024
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We present an ice-free season temperature based on brGDGTs over last 15 kyr on the eastern Tibetan Plateau (TP). The result shows that Holocene Thermal Maximum occurred during 8–3.5 ka, which lags behind pollen-based temperature recorded in same core, indicating a significant seasonal bias between different proxies. We also investigated previously published brGDGT-based temperatures on the TP to determine the pattern of Holocene temperature changes and possible reasons for the diverse records.
Léa d'Oliveira, Lucas Dugerdil, Guillemette Ménot, Allowen Evin, Serge D. Muller, Salomé Ansanay-Alex, Julien Azuara, Colline Bonnet, Laurent Bremond, Mehmet Shah, and Odile Peyron
Clim. Past, 19, 2127–2156, https://doi.org/10.5194/cp-19-2127-2023, https://doi.org/10.5194/cp-19-2127-2023, 2023
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In southern Europe, Holocene climate variability is characterized by a strong heterogeneity whose patterns are still poorly understood. Here, a multi-proxy approach (pollen and biomarkers) is applied to the Canroute sequence to reconstruct the climatic variation over the last 15 000 years in southern Massif Central, France. Results reveal that reconstructions of regional climate trends notably differ depending on proxies and sites, notably concerning the presence of a Holocene thermal maximum.
Esmeralda Cruz-Silva, Sandy P. Harrison, I. Colin Prentice, Elena Marinova, Patrick J. Bartlein, Hans Renssen, and Yurui Zhang
Clim. Past, 19, 2093–2108, https://doi.org/10.5194/cp-19-2093-2023, https://doi.org/10.5194/cp-19-2093-2023, 2023
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We examined 71 pollen records (12.3 ka to present) in the eastern Mediterranean, reconstructing climate changes. Over 9000 years, winters gradually warmed due to orbital factors. Summer temperatures peaked at 4.5–5 ka, likely declining because of ice sheets. Moisture increased post-11 kyr, remaining high from 10–6 kyr before a slow decrease. Climate models face challenges in replicating moisture transport.
Giselle Utida, Francisco W. Cruz, Mathias Vuille, Angela Ampuero, Valdir F. Novello, Jelena Maksic, Gilvan Sampaio, Hai Cheng, Haiwei Zhang, Fabio Ramos Dias de Andrade, and R. Lawrence Edwards
Clim. Past, 19, 1975–1992, https://doi.org/10.5194/cp-19-1975-2023, https://doi.org/10.5194/cp-19-1975-2023, 2023
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We reconstruct the Intertropical Convergence Zone (ITCZ) behavior during the past 3000 years over northeastern Brazil based on oxygen stable isotopes of stalagmites. Paleoclimate changes were mainly forced by the tropical South Atlantic and tropical Pacific sea surface temperature variability. We describe an ITCZ zonal behavior active around 1100 CE and the period from 1500 to 1750 CE. The dataset also records historical droughts that affected modern human population in this area of Brazil.
Mengmeng Liu, Yicheng Shen, Penelope González-Sampériz, Graciela Gil-Romera, Cajo J. F. ter Braak, Iain Colin Prentice, and Sandy P. Harrison
Clim. Past, 19, 803–834, https://doi.org/10.5194/cp-19-803-2023, https://doi.org/10.5194/cp-19-803-2023, 2023
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We reconstructed the Holocene climates in the Iberian Peninsula using a large pollen data set and found that the west–east moisture gradient was much flatter than today. We also found that the winter was much colder, which can be expected from the low winter insolation during the Holocene. However, summer temperature did not follow the trend of summer insolation, instead, it was strongly correlated with moisture.
Hannah M. Palmer, Veronica Padilla Vriesman, Caitlin M. Livsey, Carina R. Fish, and Tessa M. Hill
Clim. Past, 19, 199–232, https://doi.org/10.5194/cp-19-199-2023, https://doi.org/10.5194/cp-19-199-2023, 2023
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To better understand and contextualize modern climate change, this systematic review synthesizes climate and oceanographic patterns in the Western United States and California Current System through the most recent 11.75 kyr. Through a literature review and coded analysis of past studies, we identify distinct environmental phases through time and linkages between marine and terrestrial systems. We explore climate change impacts on ecosystems and human–environment interactions.
Michael P. Erb, Nicholas P. McKay, Nathan Steiger, Sylvia Dee, Chris Hancock, Ruza F. Ivanovic, Lauren J. Gregoire, and Paul Valdes
Clim. Past, 18, 2599–2629, https://doi.org/10.5194/cp-18-2599-2022, https://doi.org/10.5194/cp-18-2599-2022, 2022
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To look at climate over the past 12 000 years, we reconstruct spatial temperature using natural climate archives and information from model simulations. Our results show mild global mean warmth around 6000 years ago, which differs somewhat from past reconstructions. Undiagnosed seasonal biases in the data could explain some of the observed temperature change, but this still would not explain the large difference between many reconstructions and climate models over this period.
Anson W. Mackay, Vivian A. Felde, David W. Morley, Natalia Piotrowska, Patrick Rioual, Alistair W. R. Seddon, and George E. A. Swann
Clim. Past, 18, 363–380, https://doi.org/10.5194/cp-18-363-2022, https://doi.org/10.5194/cp-18-363-2022, 2022
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We investigated the diversity of algae called diatoms in Lake Baikal, the oldest and deepest lake in the world, because algae sit at the base of aquatic foodwebs and provide energy (in the form of primary production) for other organisms to use. Diatom diversity and primary production have been influenced by both long-term and abrupt climate change over the past 16 000 years. The shape of these responses appears to be time-period specific.
Maierdang Keyimu, Zongshan Li, Bojie Fu, Guohua Liu, Fanjiang Zeng, Weiliang Chen, Zexin Fan, Keyan Fang, Xiuchen Wu, and Xiaochun Wang
Clim. Past, 17, 2381–2392, https://doi.org/10.5194/cp-17-2381-2021, https://doi.org/10.5194/cp-17-2381-2021, 2021
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We created a residual tree-ring width chronology and reconstructed non-growth-season precipitation (NGSP) over the period spanning 1600–2005 in the southeastern Tibetan Plateau (SETP), China. Reconstruction model verification as well as similar variations of NGSP reconstruction and Palmer Drought Severity Index reconstructions from the surrounding region indicate the reliability of the present reconstruction. Our reconstruction is representative of NGSP variability of a large region in the SETP.
Caroline Welte, Jens Fohlmeister, Melina Wertnik, Lukas Wacker, Bodo Hattendorf, Timothy I. Eglinton, and Christoph Spötl
Clim. Past, 17, 2165–2177, https://doi.org/10.5194/cp-17-2165-2021, https://doi.org/10.5194/cp-17-2165-2021, 2021
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Stalagmites are valuable climate archives, but unlike other proxies the use of stable carbon isotopes (δ13C) is still difficult. A stalagmite from the Austrian Alps was analyzed using a new laser ablation method for fast radiocarbon (14C) analysis. This allowed 14C and δ13C to be combined, showing that besides soil and bedrock a third source is contributing during periods of warm, wet climate: old organic matter.
Nora Richter, James M. Russell, Johanna Garfinkel, and Yongsong Huang
Clim. Past, 17, 1363–1383, https://doi.org/10.5194/cp-17-1363-2021, https://doi.org/10.5194/cp-17-1363-2021, 2021
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We present a reconstruction of winter–spring temperatures developed using organic proxies preserved in well-dated lake sediments from southwest Iceland to assess seasonal temperature changes in the North Atlantic region over the last 2000 years. The gradual warming trend observed in our record is likely influenced by sea surface temperatures, which are sensitive to changes in ocean circulation and seasonal insolation, during the winter and spring season.
Lucas Dugerdil, Sébastien Joannin, Odile Peyron, Isabelle Jouffroy-Bapicot, Boris Vannière, Bazartseren Boldgiv, Julia Unkelbach, Hermann Behling, and Guillemette Ménot
Clim. Past, 17, 1199–1226, https://doi.org/10.5194/cp-17-1199-2021, https://doi.org/10.5194/cp-17-1199-2021, 2021
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Since the understanding of Holocene climate change appears to be a relevant issue for future climate change, the paleoclimate calibrations have to be improved. Here, surface samples from Mongolia and Siberia were analyzed to provide new calibrations for pollen and biomarker climate models. These calibrations appear to be more powerful than global calibrations, especially in an arid central Asian context. These calibrations will improve the understanding of monsoon Holocene oscillations.
Justin T. Maxwell, Grant L. Harley, Trevis J. Matheus, Brandon M. Strange, Kayla Van Aken, Tsun Fung Au, and Joshua C. Bregy
Clim. Past, 16, 1901–1916, https://doi.org/10.5194/cp-16-1901-2020, https://doi.org/10.5194/cp-16-1901-2020, 2020
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We found that increasing the density of chronologies in the tree-ring network resulted in estimated soil moisture conditions that better matched the spatial variability of the values that were instrumentally recorded for droughts and, to a lesser extent, pluvials. By sampling trees in 2010 compared to 1980, the sensitivity of tree rings to soil moisture decreased in the southern portion of our region, where severe drought conditions have been absent over recent decades.
Stefano Segadelli, Federico Grazzini, Veronica Rossi, Margherita Aguzzi, Silvia Marvelli, Marco Marchesini, Alessandro Chelli, Roberto Francese, Maria Teresa De Nardo, and Sandro Nanni
Clim. Past, 16, 1547–1564, https://doi.org/10.5194/cp-16-1547-2020, https://doi.org/10.5194/cp-16-1547-2020, 2020
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In an attempt to consolidate trends in the hydrological cycle induced by recent warming, we conducted a multidisciplinary study combining meteorological data, climate proxies from the literature, and original coring and pollen data acquired in an area that has been hit by record-breaking precipitation events. A detailed study of recent flash-flood deposits compared with fossil peat bog and lake sediments supports the expected increase in precipitation intensity during warm climatic phases.
Bo Cheng, Jennifer Adams, Jianhui Chen, Aifeng Zhou, Qing Zhang, and Anson W. Mackay
Clim. Past, 16, 543–554, https://doi.org/10.5194/cp-16-543-2020, https://doi.org/10.5194/cp-16-543-2020, 2020
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The Qinling mountains in China are biodiversity rich. We studied one of the high-latitude lakes on Mount Taibai with a view to looking at how aquatic diversity responded to long-term changes in climate over the past 3500 years. We specifically looked at a group of single-celled algae called diatoms, as they are very sensitive to the environment. We found that these algae changed gradually over time, but they showed abrupt change during the period known as the Little Ice Age, about 400 years ago.
Xingxing Liu, Youbin Sun, Jef Vandenberghe, Peng Cheng, Xu Zhang, Evan J. Gowan, Gerrit Lohmann, and Zhisheng An
Clim. Past, 16, 315–324, https://doi.org/10.5194/cp-16-315-2020, https://doi.org/10.5194/cp-16-315-2020, 2020
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The East Asian summer monsoon and winter monsoon are anticorrelated on a centennial timescale during 16–1 ka. The centennial monsoon variability is connected to changes of both solar activity and North Atlantic cooling events during the Early Holocene. Then, North Atlantic cooling became the major forcing of events during the Late Holocene. This work presents the great challenge and potential to understand the response of the monsoon system to global climate changes in the past and the future.
Antonio García-Alix, Jaime L. Toney, Gonzalo Jiménez-Moreno, Carmen Pérez-Martínez, Laura Jiménez, Marta Rodrigo-Gámiz, R. Scott Anderson, Jon Camuera, Francisco J. Jiménez-Espejo, Dhais Peña-Angulo, and María J. Ramos-Román
Clim. Past, 16, 245–263, https://doi.org/10.5194/cp-16-245-2020, https://doi.org/10.5194/cp-16-245-2020, 2020
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In this paper we identify warming thresholds, rates, and forcing mechanisms from a novel alpine temperature record of the southern Iberian Peninsula during the Common Era in order to contextualize the modern warming and its potential impact on these vulnerable alpine ecosystems. To do so, we have developed and applied the first lacustrine temperature calibration in alpine lakes for algal compounds, called long-chain alkyl diols, which is a significant advance in biomarker paleothermometry.
Stef Vansteenberge, Niels J. de Winter, Matthias Sinnesael, Sophie Verheyden, Steven Goderis, Stijn J. M. Van Malderen, Frank Vanhaecke, and Philippe Claeys
Clim. Past, 16, 141–160, https://doi.org/10.5194/cp-16-141-2020, https://doi.org/10.5194/cp-16-141-2020, 2020
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We measured the chemical composition (trace-element concentrations and stable-isotope ratios) of a Belgian speleothem that deposited annual layers. Our sub-annual resolution dataset allows us to investigate how the chemistry of this speleothem recorded changes in the environment and climate in northwestern Europe. We then use this information to reconstruct climate change during the 16th and 17th century on the seasonal scale and demonstrate that environmental change drives speleothem chemistry.
Alexander Land, Sabine Remmele, Jutta Hofmann, Daniel Reichle, Margaret Eppli, Christian Zang, Allan Buras, Sebastian Hein, and Reiner Zimmermann
Clim. Past, 15, 1677–1690, https://doi.org/10.5194/cp-15-1677-2019, https://doi.org/10.5194/cp-15-1677-2019, 2019
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With the use of precipitation sensitive oak ring-width series from the Main River region (southern Germany) a 2000-year long hydroclimate reconstruction has been developed. The ring series are sensitive to the sum of rainfall from 26 February to 6 July. This region suffered from severe, long-lasting droughts in the past two millennia (e.g., AD 500/510s, 940s, 1170s, 1390s and 1160s). In the AD 550s, 1050s, 1310s and 1480s, multi-year periods with high rainfall hit the region.
Nils Weitzel, Andreas Hense, and Christian Ohlwein
Clim. Past, 15, 1275–1301, https://doi.org/10.5194/cp-15-1275-2019, https://doi.org/10.5194/cp-15-1275-2019, 2019
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A new method for probabilistic spatial reconstructions of past climate states is presented, which combines pollen data with a multi-model ensemble of climate simulations in a Bayesian framework. The approach is applied to reconstruct summer and winter temperature in Europe during the mid-Holocene. Our reconstructions account for multiple sources of uncertainty and are well suited for quantitative statistical analyses of the climate under different forcing conditions.
Inken Heidke, Denis Scholz, and Thorsten Hoffmann
Clim. Past, 15, 1025–1037, https://doi.org/10.5194/cp-15-1025-2019, https://doi.org/10.5194/cp-15-1025-2019, 2019
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This is the first quantitative study of lignin biomarkers in stalagmites and cave drip water. Lignin is only produced by higher plants; therefore, its analysis can be used to reconstruct the vegetation of the past. We compared our lignin results with stable isotope and trace element records from the same samples and found correlations or similarities with P, Ba, U and Mg concentrations as well as δ13C values. These results can help to better interpret other vegetation proxies.
Johannes Hepp, Lorenz Wüthrich, Tobias Bromm, Marcel Bliedtner, Imke Kathrin Schäfer, Bruno Glaser, Kazimierz Rozanski, Frank Sirocko, Roland Zech, and Michael Zech
Clim. Past, 15, 713–733, https://doi.org/10.5194/cp-15-713-2019, https://doi.org/10.5194/cp-15-713-2019, 2019
Olga V. Churakova (Sidorova), Marina V. Fonti, Matthias Saurer, Sébastien Guillet, Christophe Corona, Patrick Fonti, Vladimir S. Myglan, Alexander V. Kirdyanov, Oksana V. Naumova, Dmitriy V. Ovchinnikov, Alexander V. Shashkin, Irina P. Panyushkina, Ulf Büntgen, Malcolm K. Hughes, Eugene A. Vaganov, Rolf T. W. Siegwolf, and Markus Stoffel
Clim. Past, 15, 685–700, https://doi.org/10.5194/cp-15-685-2019, https://doi.org/10.5194/cp-15-685-2019, 2019
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We present a unique dataset of multiple tree-ring and stable isotope parameters, representing temperature-sensitive Siberian ecotones, to assess climatic impacts after six large stratospheric volcanic eruptions at 535, 540, 1257, 1640, 1815, and 1991 CE. Besides the well-documented effects of temperature derived from tree-ring width and latewood density, stable carbon and oxygen isotopes in tree-ring cellulose provide information about moisture and sunshine duration changes after the events.
Monica Bini, Giovanni Zanchetta, Aurel Perşoiu, Rosine Cartier, Albert Català, Isabel Cacho, Jonathan R. Dean, Federico Di Rita, Russell N. Drysdale, Martin Finnè, Ilaria Isola, Bassem Jalali, Fabrizio Lirer, Donatella Magri, Alessia Masi, Leszek Marks, Anna Maria Mercuri, Odile Peyron, Laura Sadori, Marie-Alexandrine Sicre, Fabian Welc, Christoph Zielhofer, and Elodie Brisset
Clim. Past, 15, 555–577, https://doi.org/10.5194/cp-15-555-2019, https://doi.org/10.5194/cp-15-555-2019, 2019
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The Mediterranean region has returned some of the clearest evidence of a climatically dry period occurring approximately 4200 years ago. We reviewed selected proxies to infer regional climate patterns between 4.3 and 3.8 ka. Temperature data suggest a cooling anomaly, even if this is not uniform, whereas winter was drier, along with dry summers. However, some exceptions to this prevail, where wetter condition seems to have persisted, suggesting regional heterogeneity.
Amy J. Dougherty, Jeong-Heon Choi, Chris S. M. Turney, and Anthony Dosseto
Clim. Past, 15, 389–404, https://doi.org/10.5194/cp-15-389-2019, https://doi.org/10.5194/cp-15-389-2019, 2019
Áslaug Geirsdóttir, Gifford H. Miller, John T. Andrews, David J. Harning, Leif S. Anderson, Christopher Florian, Darren J. Larsen, and Thor Thordarson
Clim. Past, 15, 25–40, https://doi.org/10.5194/cp-15-25-2019, https://doi.org/10.5194/cp-15-25-2019, 2019
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Compositing climate proxies in sediment from seven Iceland lakes documents abrupt summer cooling between 4.5 and 4.0 ka, statistically indistinguishable from 4.2 ka. Although the decline in summer insolation was an important factor, a combination of superposed changes in ocean circulation and explosive Icelandic volcanism were likely responsible for the abrupt perturbation recorded by our proxies. Lake and catchment proxies recovered to a colder equilibrium state following the perturbation.
Haiwei Zhang, Hai Cheng, Yanjun Cai, Christoph Spötl, Gayatri Kathayat, Ashish Sinha, R. Lawrence Edwards, and Liangcheng Tan
Clim. Past, 14, 1805–1817, https://doi.org/10.5194/cp-14-1805-2018, https://doi.org/10.5194/cp-14-1805-2018, 2018
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The collapses of several Neolithic cultures in China are considered to have been associated with abrupt climate change during the 4.2 ka BP event; however, the hydroclimate of this event in China is still poorly known. Based on stalagmite records from monsoonal China, we found that north China was dry but south China was wet during this event. We propose that the rain belt remained longer at its southern position, giving rise to a pronounced humidity gradient between north and south China.
Alice Callegaro, Dario Battistel, Natalie M. Kehrwald, Felipe Matsubara Pereira, Torben Kirchgeorg, Maria del Carmen Villoslada Hidalgo, Broxton W. Bird, and Carlo Barbante
Clim. Past, 14, 1543–1563, https://doi.org/10.5194/cp-14-1543-2018, https://doi.org/10.5194/cp-14-1543-2018, 2018
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Holocene fires and vegetation are reconstructed using different molecular markers with a single analytical method, applied for the first time to lake sediments from Tibet. The early Holocene shows oscillations between grasses and conifers, with smouldering fires represented by levoglucosan peaks, and high-temperature fires represented by PAHs. The lack of human FeSts excludes local human influence on fire and vegetation changes. Late Holocene displays an increase in local to regional combustion.
Kees Nooren, Wim Z. Hoek, Brian J. Dermody, Didier Galop, Sarah Metcalfe, Gerald Islebe, and Hans Middelkoop
Clim. Past, 14, 1253–1273, https://doi.org/10.5194/cp-14-1253-2018, https://doi.org/10.5194/cp-14-1253-2018, 2018
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We present two new palaeoclimatic records for the central Maya lowlands, adding valuable new insights to the impact of climate change on the development of Maya civilisation. Lake Tuspan's diatom record is indicative of precipitation changes at a local scale, while a beach ridge elevation record from the world's largest late Holocene beach ridge plain provides a regional picture.
Markus Czymzik, Raimund Muscheler, Florian Adolphi, Florian Mekhaldi, Nadine Dräger, Florian Ott, Michał Słowinski, Mirosław Błaszkiewicz, Ala Aldahan, Göran Possnert, and Achim Brauer
Clim. Past, 14, 687–696, https://doi.org/10.5194/cp-14-687-2018, https://doi.org/10.5194/cp-14-687-2018, 2018
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Our results provide a proof of concept for facilitating 10Be in varved lake sediments as a novel synchronization tool required for investigating leads and lags of proxy responses to climate variability. They also point to some limitations of 10Be in these archives mainly connected to in-lake sediment resuspension processes.
Darrell S. Kaufman and PAGES 2k special-issue editorial team
Clim. Past, 14, 593–600, https://doi.org/10.5194/cp-14-593-2018, https://doi.org/10.5194/cp-14-593-2018, 2018
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We explain the procedure used to attain a high and consistent level of data stewardship across a special issue of the journal Climate of the Past. We discuss the challenges related to (1) determining which data are essential for public archival, (2) using data generated by others, and (3) understanding data citations. We anticipate that open-data sharing in paleo sciences will accelerate as the advantages become more evident and as practices that reduce data loss become the accepted convention.
Haipeng Wang, Jianhui Chen, Shengda Zhang, David D. Zhang, Zongli Wang, Qinghai Xu, Shengqian Chen, Shijin Wang, Shichang Kang, and Fahu Chen
Clim. Past, 14, 383–396, https://doi.org/10.5194/cp-14-383-2018, https://doi.org/10.5194/cp-14-383-2018, 2018
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The chironomid-inferred temperature record from Gonghai Lake exhibits a stepwise decreasing trend since 4 ka. A cold event in the Era of Disunity, the Sui-Tang Warm Period, the Medieval Warm Period and the Little Ice Age can all be recognized in our record, as well as in many other temperature reconstructions in China. Local wars in Shanxi Province, documented in the historical literature during the past 2700 years, are statistically significantly correlated with changes in temperature.
Hansi K. A. Singh, Gregory J. Hakim, Robert Tardif, Julien Emile-Geay, and David C. Noone
Clim. Past, 14, 157–174, https://doi.org/10.5194/cp-14-157-2018, https://doi.org/10.5194/cp-14-157-2018, 2018
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The Atlantic Multidecadal Oscillation (AMO) is prominent in the climate system. We study the AMO over the last 2000 years using a novel proxy framework, the Last Millennium Reanalysis. We find that the AMO is linked to continental warming, Arctic sea ice retreat, and an Atlantic precipitation shift. Low clouds decrease globally. We find no distinct multidecadal spectral peak in the AMO over the last 2 millennia, suggesting that human activities may have enhanced the AMO in the modern era.
Ny Riavo Gilbertinie Voarintsoa, Loren Bruce Railsback, George Albert Brook, Lixin Wang, Gayatri Kathayat, Hai Cheng, Xianglei Li, Richard Lawrence Edwards, Amos Fety Michel Rakotondrazafy, and Marie Olga Madison Razanatseheno
Clim. Past, 13, 1771–1790, https://doi.org/10.5194/cp-13-1771-2017, https://doi.org/10.5194/cp-13-1771-2017, 2017
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This research has been an investigation of two stalagmites from two caves in NW Madagascar to reconstruct the region's paleoenvironmental changes, and to understand the linkage of such changes to the dynamics of the ITCZ. Stable isotopes, mineralogy, and petrography suggest wetter climate conditions than today during the early and late Holocene, when the mean ITCZ was south, and drier during the mid-Holocene when the ITCZ was north.
Wei Ding, Qinghai Xu, and Pavel E. Tarasov
Clim. Past, 13, 1285–1300, https://doi.org/10.5194/cp-13-1285-2017, https://doi.org/10.5194/cp-13-1285-2017, 2017
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Pollen-based past climate reconstruction for regions with long-term human occupation is always controversial. We examined the bias induced by the human impact on vegetation in a climate reconstruction for temperate eastern China by comparing the deviations in the reconstructed results for a fossil record based on two pollen–climate calibration sets. Climatic signals in pollen assemblages are indeed obscured by human impact; however, the extent of the bias could be assessed.
Oliver Rach, Ansgar Kahmen, Achim Brauer, and Dirk Sachse
Clim. Past, 13, 741–757, https://doi.org/10.5194/cp-13-741-2017, https://doi.org/10.5194/cp-13-741-2017, 2017
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Currently, reconstructions of past changes in the hydrological cycle are usually qualitative, which is a major drawback for testing the accuracy of models in predicting future responses. Here we present a proof of concept of a novel approach to deriving quantitative paleohydrological data, i.e. changes in relative humidity, from lacustrine sediment archives, employing a combination of organic geochemical methods and plant physiological modeling.
Juan José Gómez-Navarro, Eduardo Zorita, Christoph C. Raible, and Raphael Neukom
Clim. Past, 13, 629–648, https://doi.org/10.5194/cp-13-629-2017, https://doi.org/10.5194/cp-13-629-2017, 2017
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This contribution aims at assessing to what extent the analogue method, a classic technique used in other branches of meteorology and climatology, can be used to perform gridded reconstructions of annual temperature based on the limited information from available but un-calibrated proxies spread across different locations of the world. We conclude that it is indeed possible, albeit with certain limitations that render the method comparable to more classic techniques.
Atsushi Okazaki and Kei Yoshimura
Clim. Past, 13, 379–393, https://doi.org/10.5194/cp-13-379-2017, https://doi.org/10.5194/cp-13-379-2017, 2017
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Data assimilation has been successfully applied in the field of paleoclimatology to reconstruct past climate. However, data reconstructed from proxies have been assimilated, as opposed to the actual proxy values, which prevented full utilization of the information recorded in the proxies. This study propose a new data assimilation system in which actual proxy data are directly assimilated.
Enlou Zhang, Jie Chang, Yanmin Cao, Hongqu Tang, Pete Langdon, James Shulmeister, Rong Wang, Xiangdong Yang, and Ji Shen
Clim. Past, 13, 185–199, https://doi.org/10.5194/cp-13-185-2017, https://doi.org/10.5194/cp-13-185-2017, 2017
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This paper reports the first development of sub-fossil chironomid-based mean July temperature transfer functions from China. The transfer functions yield reliable reconstructions that are comparable to the instrumental record. The application of this new tool will provide long-term quantitative palaeoclimate estimates from south-western China which is a critical region for understanding the dynamic and evolution of the Indian Ocean south-west Monsoon system.
Qing Yang, Xiaoqiang Li, Xinying Zhou, Keliang Zhao, and Nan Sun
Clim. Past, 12, 2229–2240, https://doi.org/10.5194/cp-12-2229-2016, https://doi.org/10.5194/cp-12-2229-2016, 2016
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The fossilized seeds of common millet are suited to the production of quantitative Holocene precipitation reconstructions. Our reconstructed results showed that summer precipitation from 7.7–3.4 ka BP was ~ 50 mm, or 17 % higher than present levels. Maximal mean summer precipitation peaked at 414 mm during 6.1–5.5 ka BP, ~ 109 mm, or 36 % higher than today, indicating the EASM peaked at this time. This work can provide a new proxy for further research into continuous paleoprecipitation sequences.
Michael Deininger, Martin Werner, and Frank McDermott
Clim. Past, 12, 2127–2143, https://doi.org/10.5194/cp-12-2127-2016, https://doi.org/10.5194/cp-12-2127-2016, 2016
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This study investigates the NAO (Northern Atlantic Oscillation)-related mechanisms that control winter precipitation stable oxygen and hydrogen isotope gradients across Europe. The results show that past longitudinal stable oxygen and hydrogen isotope gradients in European rainfall stored in palaeoclimate archives (e.g. speleothems) can be used to infer the past winter NAO modes from its variations.
Liangjun Zhu, Yuandong Zhang, Zongshan Li, Binde Guo, and Xiaochun Wang
Clim. Past, 12, 1485–1498, https://doi.org/10.5194/cp-12-1485-2016, https://doi.org/10.5194/cp-12-1485-2016, 2016
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We present a 368-year late summer maximum temperature reconstruction based on spruce tree rings. It touches on the critical topic of climate reconstruction in the eastern edge of Tibetan Plateau and represents an extension and enhancement of climate records for this area. The Little Ice Age was well represented and 20th century warming was not obvious in this reconstruction. This temperature variation may be affected by global land–sea atmospheric circulation as well as solar and volcanic forcing.
Frazer Matthews-Bird, Stephen J. Brooks, Philip B. Holden, Encarni Montoya, and William D. Gosling
Clim. Past, 12, 1263–1280, https://doi.org/10.5194/cp-12-1263-2016, https://doi.org/10.5194/cp-12-1263-2016, 2016
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Chironomidae are a family of two-winged aquatic fly of the order Diptera. The family is species rich (> 5000 described species) and extremely sensitive to environmental change, particualy temperature. Across the Northern Hemisphere, chironomids have been widely used as paleotemperature proxies as the chitinous remains of the insect are readily preserved in lake sediments. This is the first study using chironomids as paleotemperature proxies in tropical South America.
Karsten Schittek, Sebastian T. Kock, Andreas Lücke, Jonathan Hense, Christian Ohlendorf, Julio J. Kulemeyer, Liliana C. Lupo, and Frank Schäbitz
Clim. Past, 12, 1165–1180, https://doi.org/10.5194/cp-12-1165-2016, https://doi.org/10.5194/cp-12-1165-2016, 2016
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Cushion peatlands are versatile climate archives for the study of past environmental changes. We present the environmental history for the last 2100 years of Cerro Tuzgle peatland, which is located in the NW Argentine Puna. The results reflect prominent late Holocene climate anomalies and provide evidence that Northern Hemisphere climate oscillations were extensive. Volcanic forcing at the beginning of the 19th century seems to have had an impact on climatic settings in the Central Andes
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Short summary
Indirect evidence on past climate comes from the former composition of ecological communities such as plants, preserved as pollen grains in sediments of lakes. Transfer functions convert relative counts of species to a climatologically meaningful scale (e.g. annual mean temperature in degrees C). We show that the fundamental assumptions in the algorithms impact the reconstruction results in he idealized model world, in particular if the reconstructed variables were not ecologically relevant.
Indirect evidence on past climate comes from the former composition of ecological communities...
