Freshwater, in the form of glacial runoff, is hypothesized to play a critical role in centennial- to millennial-scale climate variability and climate transitions. We track the routing of glaciologically constrained freshwater volumes in glacial ocean simulations. Our simulations capture important generally not well-represented small-scale features (boundary currents, eddies). We show that the dilution of freshwater as it is transported to key climate regions reduces the freshening to 20 %–60 %.

The Eocene–Oligocene climate transition (EOT) is one of the most drastic climate changes of the Cenozoic era and the final stage of the shift from ice-free to icehouse Earth. Here we present high-resolution records (geophysical, geochemical and sedimentological proxy data) of the EOT from lake deposits to detect the atmospheric expression of the EOT via the hydrological cycle. Such records provide strong constraints on climate modeling and on our comprehension of the forcing mechanisms of EOT.

This paper presents temperature and pressure measurements from the 37 stations of the late 18th century network of the Societas Meteorologica Palatina, in addition to providing an inventory of the available observations, most of which have been digitised. The quality of the recovered series is relatively good, as demonstrated by two case studies. Early instrumental data such as these will help to explore past climate and weather extremes in Europe in greater detail.

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.

Here, we use the latest insights for GDGT and dinocyst-based paleotemperature and paleoenvironmental reconstructions in late Cretaceous–early Oligocene sediments from ODP Site 1172 (East Tasman Plateau, Australia). We reconstruct strong river runoff during the Paleocene–early Eocene, a progressive decline thereafter with increased wet/dry seasonality in the northward-drifting hinterland. Our critical review leaves the anomalous warmth of the Eocene SW Pacific Ocean unexplained.

In this work, we have studied the behaviour of El Niño events in the mid-Pliocene, a period of around 3 million years ago, using a collection of 17 climate models. It is an interesting period to study, as it saw similar atmospheric carbon dioxide levels to the present day. We find that the El Niño events were less strong in the mid-Pliocene simulations, when compared to pre-industrial climate. Our results could help to interpret El Niño behaviour in future climate projections.

Glacier reconstructions provide insights into past climatic conditions and elucidate processes and feedbacks that modulate the climate system both in the past and present. We investigate the transition from the last glacial to the current interglacial and generate beryllium-10 moraine chronologies in glaciated catchments of the eastern European Alps. We find that rapid warming was superimposed by centennial-scale cold phases that appear to have influenced large parts of the Northern Hemisphere.

Using the comprehensive Earth system model, MPI-ESM1.2, we explore the global Holocene vegetation changes and interpret them in terms of the Holocene climate change. The model results reveal that most of the Holocene vegetation transitions seen outside the high northern latitudes can be attributed to modifications in the intensity of the global summer monsoons.

Modern climate change drives us to look to the past to understand how well prior life adapted to warm periods. In the early Eocene, a warm period approximately 50 million years ago, southwestern Wyoming was covered by a giant lake. This lake and surrounding environments made for excellent preservation of ancient soils, plant fossils, and more. Using geochemical tools and plant fossils, we determine the region was a warm, wet forest and that elevated temperatures were maintained by volcanoes.

Understanding the potential processes responsible for large-scale hydrological cycle changes in a warmer climate is of great importance. Our study implies that an imbalance in interhemispheric atmospheric energy during the mid-Pliocene could have led to changes in the dynamic effect, offsetting the thermodynamic effect and, hence, altering mid-Pliocene hydroclimate cycling. Moreover, a robust westward shift in the Pacific Walker circulation can moisten the northern Indian Ocean.

We use regional climate simulations for the Last Glacial Maximum to reconstruct permafrost and to identify areas of thermal contraction cracking of the ground in western Europe. We find ground cracking, a precondition for the development of permafrost proxies, south of the probable permafrost border, implying that permafrost was not the limiting factor for proxy development. A good agreement with permafrost and climate proxy data is achieved when easterly winds are modelled more frequently.

Climate field reconstructions (CFRs) estimate spatiotemporal climate conditions hundreds to thousands of years into the past. Assessing CFR skills is critical for improving their interpretation and ultimately for deriving better CFR estimates. We apply new methods for assessing spatiotemporal skill using formalized null hypotheses to derive a detailed assessment of why CFR skill varies across multiple methods, with implications for improving future CFR estimates.

An unidentified eruption in 1831 was one of the largest volcanic climate forcing events of the nineteenth century. We use reported observations of a blue sun to reconstruct the transport of an aerosol plume from that eruption and, hence, identify it as the 1831 eruption of Ferdinandea, near Sicily. We propose that, although it was only a modest eruption, its volcanic plume was enriched with sulfur from sedimentary deposits and that meteorological conditions helped it reach the stratosphere.

Peatlands are some of the best environments for storing carbon; thus, comprehending how much carbon can be stored and how amounts have changed through time is important to understand carbon cycling. We analysed nine peatlands from central–eastern Europe to look at how carbon storage in mountain bogs has changed over the last 10 000 years. We conclude that human activity is the main driver of changes in storage levels over the past 4000 years; prior to this, climate was the primary driver.

Laminated sediments from the deepest part of the Dead Sea unravel the hydrological response of the eastern Mediterranean to past climate changes. This study demonstrates the importance of geological archives in complementing modern hydrological measurements that do not fully capture natural hydroclimatic variability, which is crucial to configure for understanding the impact of climate change on the hydrological cycle in subtropical regions.