Abstracted/indexed

We present a first high-temporal-resolution record of mineral composition in a Greenland ice core over the past 100 years using SEM-EDS analysis. Our main finding is the ice core dust composition varied on multi-decadal scales that can be attributed to the local temperature changes. We also reveal that the western coast of Greenland is main source of the ice core dust in warming periods (1915 to 1949 and 2005 to 2013), which is likely due to an increase of dust sourced from local ice-free areas.

In this research article, we present new paleoceanographic reconstructions for the Oligocene (33.7–25.4 Ma) offshore Cape Adare, Ross Sea, Antarctica. Our study of dinoflagellate cysts assemblages and lipid biomarkers (TEX₈₆) indicate warm-temperate sea surface conditions. We propose that warm offshore conditions delivered heat to Antarctica, causing surface melt and glacial retreat during warm orbitals and promoted precipitation during cold orbitals sustaining marine terminations of ice caps.

In this paper, we present new sedimentological, geochemical, and mineralogical data exploring the environmental response to climatic and volcanic impact during the Paleocene-Eocene Thermal Maximum (~ 55.9 Ma; PETM). Our data suggests a rise in continental weathering and a shift to anoxic-exinic conditions. This indicates a rapid environmental response to changes in the carbon cycle and temperatures, and highlights the important role of shelf areas as carbon sinks driving the PETM recovery.

The Last Interglacial period (LIG) is characterised by strong orbital forcing compared to the present day. This study compares the mean climate state of the LIG to the pre-industrial period as simulated by the ACCESS-ESM1.5, with focus on the southern hemispheric monsoons which are shown to be consistently weakened. This is associated with cooler terrestrial conditions in austral summer due to decreased insolation, and greater pressure and subsidence over land from Hadley cell strengthening.

This study assesses the importance of resolution and land-atmosphere feedbacks on European climate. We performed an asynchronously coupled experiment that combined a global climate model (~100 km), a regional climate model (18 km), and a dynamic vegetation model (18 km). Modelled climate and land cover agree reasonably well with independent reconstructions based on pollen and other paleoenvironmental proxies. The regional climate is significantly influenced by land cover.

Climate models struggle to simulate a LGM ocean circulation in agreement with paleotracer data. Using a set of simulations, we test the impact of boundary conditions and other modelling choices. Model-data comparisons of sea-surface temperatures and sea-ice cover support an overall cold Southern Ocean, with implications on the AMOC strength. Changes in implemented boundary conditions are not sufficient to simulate a shallower AMOC, other mechanisms to better represent convection are required.

Far afield changes in vegetation such as those occurred over the Sahara during the middle Holocene and the consequent changes in dust emissions can affect the intensity of the South Asian Monsoon (SAM) rainfall the lengthening of the monsoon season. This remote influence is mediated by anomalies in Indian Ocean sea-surface temperatures and may have shaped the evolution of the SAM during the termination of the African Humid Period.

We investigate how the mid Holocene dust reduction affects Earth's energetics from a suite of climate simulations. Our analyses confirm the peculiar role of dust radiative effect over bright surfaces such as African deserts. We highlight a strong dependence on the dust pattern. The relative dust forcing between West Africa and the middle east impacts the relative response of Indian and African monsoons and between the western tropical Atlantic and the Atlantic meridional circulation.

The timing of North Atlantic climate changes during the penultimate interglacial (MIS 7) and terminations III-IIIa are debated. In this study we present a multi-stalagmite climate record from the Austrian Alps, whose winter temperatures are sensitive to the North Atlantic realm. The record spans 247000 to 191000 years ago with an average age uncertainty of 370 years (2 sigma). This unprecedented age control provides important time constraints on rapid climate shifts in the Alps throughout MIS 7.

To understand the interaction of the Westerlies and Indian Summer Monsoon (ISM) during the Holocene, we used paleoenvironmental reconstructions by using a sediment core from the NE Arabian Sea. We found a climatic transition period between 4.6–3 ka BP during which the ISM shifted southwards and the influence of Westerlies became prominent. Our data indicate a stronger influence of agriculture activities and enhanced soil erosion adding to the impact of Bond events after this transition period.

This paper focuses on the recovery of instrumental weather records available for Singapore and Malaysia (Straits Settlements) from the late 1780s to 1917. Taking an historical approach, the paper explore the types of records available, the circumstances of their production and their value to the scientific community.

Preliminary analyses of the annual sea salt concentrations and snowfall accumulation in a new East Antarctic ice core, Mount Brown South. We compare this record with an updated Law Dome (Dome Summit South site) ice core record over the period 1975–2016. The Mount Brown South record preserves a stronger and inverse signal for the El Niño Southern Oscillation (in austral winter and spring) compared to the Law Dome record (in summer).

Greenland ice core data show that the last glacial cycle was punctuated by a series of abrupt climate shifts comprising significant warming over Greenland, retreat of North Atlantic sea ice and atmospheric reorganization. Statistical analysis of a sample of time lags between sea ice and atmospheric changes from 16 events reveals no systematic phase relation, indicating that neither of the two was the exclusive trigger of the other. Special attention was paid to the propagation of uncertainties.

The end of the Harappan civilization in the Indus Valley around 4,200 years ago has been attributed to monsoon failure associated with a global megadrought. Using a suite of high resolution paleoclimate records from around the Indian Ocean basin we find that two consecutive droughts contributed to the end of the Harappa. A winter drought starting 4,200 years ago was followed by monsoon failure at 3,900 years ago. The double hit caused civilization decline first, and abandonment later.

The 4.2 kyr climatic event caused drought in the Mediterranean and Middle East and the collapse of the Akkadian Civilization. Outside of this region the global footprint of this event, be it drought or flood conditions, is poorly understood. This study uses a stalagmite from Madagascar to determine how the 4.2 kyr event influenced the South-East African Monsoon. We find drought in Madagascar and around Lake Malawi but wet conditions elsewhere, a pattern that resembles modern climate variability.

This study presents a multi-proxy record from lake Voёlvlei and provides new insights in the sea level and paleoclimate history of the past 8.5 ka at South Africa’s southern Cape coast. Our results show that sea level changes at the southern coast are in good agreement with the western coast of South Africa. In terms of climate, our record provides valuable insights in changing sources of precipitation at the Southern Cape coast, i.e. Westerly- and Easterly-derived precipitation contribution.

Presently, central Europe is under the influence of two types of climate, transitional and continental. The 60 ka long multiproxy speleothem data from Slovakia records the climate of the Last Interglacial cycle and its transition to Last Glacial. The interpretation of stable isotopic composition and trace element content proxies helps to distinguish which factor had the strongest influence on δ¹⁸O record shape: the local temperature, humidity, or source effect.

The stability of the Atlantic Meridional Overturning Circulation (AMOC) critically depends on its mean-state. We simulate the response of the AMOC to North Atlantic freshwater perturbations under different glacial boundary conditions. We find that a closed Bering Strait greatly increases the AMOCs sensitivity to freshwater hosing. Further, the shift from mono- to bistability strongly depends on the chosen boundary conditions, with weaker circulation states exhibiting more abrupt transitions.

This study investigates the reliability of paleo-reconstructions of the Southern Annular Mode (SAM) using climate model data. We find that reconstructions are able to, at best, capture ~ 60 % of SAM variability, with poorer reconstructions managing only 35 %. Reconstructions perform best when they use a larger number of proxies, sourced from the entire Southern Hemisphere land mass. Future reconstructions should endeavour to address both sampling and proxy-SAM correlation stability uncertainties.

Using ancient gas trapped in polar glaciers, we reconstructed the atmospheric concentrations of methane and nitrous oxide over the penultimate deglaciation to study their response to major climate changes. We show this deglaciation to be characterized by fluctuations in concentration correlated to varying strength of the meridional circulation in the Atlantic Ocean, which is believed to have modulated methane and nitrous oxide emissions during the penultimate deglaciation.

Glaciers are important freshwater sources in the Tropical Andes. Their retreat has been accelerating since the 1980s. This exposes fresh glacial sediments and facilitates the transport of coarse dust particles to the Nevado Illimani summit. Both the glacial area of Illimani and its ice core record of coarse dust particles respond to warmer conditions across the southern tropical Andes, and drier conditions over the Amazon basin.

South West Western Australia has experienced a prolonged drought in recent decades. The causes of this drought are unclear. We use an ice core from East Antarctica to reconstruct changes in rainfall over the past 2,000 years. We find that the current drought is unusual, with only two other droughts of similar severity having occurred during this period. Climate modelling shows that greenhouse gas emissions during the industrial era are likely to have contributed to the recent drying trend.

Qualitative evidence contained within historical sources provides an important record of climate variability for periods prior to the onset of systematic meteorological data collection. Before such evidence can be used for climate reconstructions, it needs to be converted to quantitative data. A common approach used is the generation of ordinal-scale climate indices. This review, written by members of the PAGES CRIAS Working Group, provides a global synthesis of the use of the index approach.

Using the temperature dependent solubility of noble gases in ocean water, we reconstruct global mean ocean temperature (MOT) over the last 700 kyr using noble gas ratios in air enclosed in polar ice cores. Our record shows that glacial MOT was about 3 °C cooler compared to the Holocene. Interglacials before 450 kyr ago were characterized by about 1.5 °C lower MOT than the Holocene. In addition, some interglacials show transient maxima in ocean temperature related to changes in ocean circulation.

We analyze Holocene temperatures reconstructed from gas-stable-isotope species measured on ancient air extracted from a Greenland ice core. Also, we compare two state of the art firn-models which are needed for the inversion of the gas-isotope data to paleo-temperature and provide detailed uncertainty estimations for the reconstructed temperature estimates. Finally, we compare our reconstructed temperatures to two recent reconstructions based on the same gas-isotope data as used here.

We analyse Holocene climate model simulation data to find the locations of Antarctic ice cores which are best suited to reconstruct local-to-regional scale temperatures. We find that the spatial decorrelation scales of the temperature variations and of the noise from precipitation intermittency set an effective sampling length scale. Following this, a single core should be located at the target site for the temperature reconstruction, a second one optimally lies more than 500 km away.