We present new offshore palaeoceanographic reconstructions for the Oligocene (33.7–24.4 Ma) in the Ross Sea, Antarctica. Our study of dinoflagellate cysts and lipid biomarkers indicates warm-temperate sea surface conditions. We posit that warm surface-ocean conditions near the continental shelf during the Oligocene promoted increased precipitation and heat delivery towards Antarctica that led to dynamic terrestrial ice sheet volumes in the warmer climate state of the Oligocene.

In this study, we tested the upper limits of U–Th dating precision by analyzing three stalagmites from the Austrian Alps that have high U concentrations. The composite record spans the penultimate interglacial (MIS 7) with an average 2σ age uncertainty of 400 years. This unprecedented age control allows us to constrain the timing of temperature shifts in the Alps during MIS 7 while offering new insight into millennial-scale changes in the North Atlantic leading up to Terminations III and IIIa.

The 1809 eruption is one of the most recent unidentified volcanic eruptions with a global climate impact. We demonstrate that climate model simulations of the 1809 eruption show generally good agreement with many large-scale temperature reconstructions and early instrumental records for a range of radiative forcing estimates. In terms of explaining the spatially heterogeneous and temporally delayed Northern Hemisphere cooling suggested by tree-ring networks, the investigation remains open.

Deep ocean temperatures are widely used as a proxy for global mean surface temperature in the past, but the underlying assumptions have not been tested. We use two unique sets of 109 climate model simulations for the last 545 million years to show that the relationship is valid for approximately the last 100 million years but breaks down for older time periods when the continents (and hence ocean circulation) are in very different positions.

Planktic and shallow benthic foraminiferal stable carbon isotope (δ¹³C) data show a rapid decline during the last deglaciation. This widespread signal was linked to respired carbon released from the deep ocean and its transport through the upper-ocean circulation. Using numerical simulations in which a stronger flux of respired carbon upwells and outcrops in the Southern Ocean, we find that the depleted δ¹³C signal is transmitted to the rest of the upper ocean through air–sea gas exchange.

During late 20th century a singular Mediterranean circulation episode called the Eastern Mediterranean Transient (EMT) event occurred. It involved changes on the seawater physical and biogeochemical properties, which can impact areas broadly. Here, using paleosimulations for the last 1000 years we found that the East Atlantic/Western Russian atmospheric mode was the main driver of the EMT-type events in the past, and enhancement of this mode was coetaneous with low solar insolation.

Human influence on fire regimes in the past is poorly understood, especially at high latitudes. We present 5 kyr of fire proxies levoglucosan, black carbon, and ammonium in the RECAP ice core in Greenland and reconstruct for the first time the fire regime in the high North Atlantic region, comprising coastal east Greenland and Iceland. Climate is the main driver of the fire regime, but at 1.1 kyr BP a contribution may be made by the deforestation resulting from Viking colonization of Iceland.

Clay minerals are witnesses of alteration conditions in continental environments. Lacking high-resolution data on clay minerals, this work highlights wet and semi-arid cycles at mid-latitude in the upper Sinemurian. The higher proportion of kaolinite in the upper part of the obtusum zone and in the oxynotum zone indicates an increase in hydrolysis conditions in a warmer period confirmed by carbon isotopes.

This study presents a multi-proxy record from Lake Voёlvlei and provides new insights into 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 into changing sources of precipitation at the southern Cape coast, i.e. westerly- and easterly-derived precipitation contribution.

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, and a second one optimally lies more than 500 km away.

This study investigates the coupling of climate and the carbon and hydrologic cycles in Asia ~ 113 million years ago to provide a more complete continental perspective on a dynamic climate interval associated with global ocean anoxic events. We find relatively cool conditions and a close coupling between the amount of CO₂ in the atmosphere, air temperature and rainfall in Asia. To quantify these shifts, chemical measurements from continental soils which formed during this interval are utilized.

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 modes of methane and nitrous oxide variability that are also found during the last deglaciation and glacial cycle.

Regional climate simulations were constructed to more accurately capture regional features of the South and Southeast Asian monsoon during the mid-Holocene. Comparison with proxies shows that our high-resolution simulations outperform those with the coarser global model in reproducing the monsoon rainfall anomalies. Incorporating the Green Sahara climate conditions over northern Africa into our simulations further strengthens the monsoon precipitation and leads to better agreement with proxies.

We investigate the impact of explicitly resolving convection on the mid-Holocene West African Monsoon rain belt by employing the ICON climate model in high resolution. While the spatial distribution and intensity of the precipitation are improved by this technique, the monsoon extents further north and the mean summer rainfall is higher in the simulation with parameterized convection.

For the first time an isotope-enabled regional climate simulation for Greenland is performed for the mid-Holocene. Simulation results are compared with observed isotope ratios in ice cores. Compared to global climate simulations, a regional downscaling improves the agreement with measured isotope concentrations. Thus, an isotope-enabled regional climate simulation constitutes a useful supplement to reconstruct regional paleo-climate conditions during the mid-Holocene in Greenland.

We assess the ¹⁴C plateau tuning technique used to date marine sediments and determine ¹⁴C marine reservoir ages. We identify problems linked to assumptions of the technique, the assumed shapes of the ¹⁴C / ¹²C records, and the sparsity and uncertainties in both atmospheric and marine data. Our concerns are supported with carbon cycle box model experiments and statistical simulations, allowing us to question the ability to tune ¹⁴C age plateaus in the context of noisy and sparse data.

This paper stresses the original contributions of Milankovitch related to his caloric seasons and his climate model giving the caloric seasons a climatological meaning.

To study the interaction of the westerlies and Indian summer monsoon (ISM) during the Holocene, we used paleoenvironmental reconstructions using a sediment core from the northeast Arabian Sea. We found a climatic transition period between 4.6 and 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 Bond event impact after this transition period.

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 multi-proxy records reveals no systematic lead or lag between the transitions of proxies that represent different climatic subsystems, and hence no evidence for a potential trigger of these so-called Dansgaard–Oeschger events can be found.

The mid-Pliocene Warm Period (~ 3.2 Ma) is often considered an analogue for near-future climate projections, and model results from the PlioMIP2 ensemble show an increase of rainfall over West Africa and the Sahara region compared to pre-industrial conditions. Though previous studies of future projections show a west–east drying–wetting contrast over the Sahel, these results indicate a uniform rainfall increase over the Sahel in warm climates characterized by increased greenhouse gas forcing.