The Pliocene was a period during which atmospheric CO₂ was similar to today (i.e. ~ 400 ppm). We present the results of model simulations carried out within the Pliocene Model Intercomparison Project Phase 2 (PlioMIP2) using the CESM 1.0.5. We find a climate that is much warmer than today, with augmented polar warming, increased precipitation, and strongly reduced sea ice cover. In addition, several leading modes of variability in temperature show an altered behaviour.

New stable isotope records from pedogenic carbonates through the ETM2, H2, and possibly I1 hyperthermals from the Bighorn Basin highlight significant spatial variability in the preservation and magnitude of these global climate events in paleosol records. These data also provide important climate context for the extensive early Eocene mammal fossil record from the southern Bighorn Basin and support previous hypotheses that pulses in mammal turnover corresponded to the ETM2 and H2 hyperthermals.

The timing of the initiation and evolution of the South Asian monsoon in the geological past is a subject of debate. Here, we present a new age model spanning the late Miocene (9 to 5 million years ago) and high-resolution records of past open-ocean biological productivity from the equatorial Indian Ocean that we interpret to reflect monsoon wind strength. Our data show no long-term intensification; however, strong orbital periodicities suggest insolation forcing of monsoon wind strength.

This study examines whether the 1600 Huaynaputina volcano eruption triggered persistent cooling in the North Atlantic. It compares previous paleoclimate simulations with new climate reconstructions from natural proxies and historical documents and finds that the reconstructions are consistent with, but do not support, an eruption trigger for persistent cooling. The study also analyzes societal impacts of climatic change in ca. 1600 and the use of historical observations in model–data comparison.

After the Marinoan snowball Earth, the climate warmed rapidly due to enhanced greenhouse conditions, and the freshwater inflow of melting glaciers caused a strong stratification of the ocean. Our climate simulations reveal a potentially only moderate global temperature increase and a break-up of the stratification within just a few thousand years. The findings give insights into the environmental conditions relevant for the geological and biological evolution during that time.

To better understand the climate conditions which lead to extensive melting of the Greenland ice sheet, we used climate models to reconstruct the climate conditions of the warmest period of the last 800 000 years, which was centered around 410 000 years ago. Surprisingly, we found that atmospheric circulation changes may have acted to reduce the melt of the ice sheet rather than enhance it, despite the extensive warmth of the time.

We unearth and analyse 2 decades of highly valuable measurements made on Mauritius at the Royal Alfred Observatory, where several distinct thermometer combinations were in use and compared, at the turn of the 20th century. This series provides unique insights into biases in early instrumental temperature records. Differences are substantial and for some instruments exhibit strong seasonality. This reinforces the critical importance of understanding early instrumental series biases.

This paper introduces a new R package to perform quantitative climate reconstructions from palaeoecological datasets. The package includes calibration data for several commonly used terrestrial (e.g. pollen) and marine (e.g. foraminifers) climate proxies to enable its use in various environments globally. In addition, the built-in graphical diagnostic tools simplify the evaluation and interpretations of the results. No coding skills are required to use crestr.

Climate models are used to predict future climate changes and as such, it is important to assess their performance in simulating past climate changes. We analyze seasonal sea-ice cover over the Southern Ocean simulated from numerical PMIP3, PMIP4 and LOVECLIM simulations during the Last Glacial Maximum (LGM). Comparing these simulations to proxy data, we provide improved estimates of LGM seasonal sea-ice cover. Our estimate of summer sea-ice extent is 20 %–30 % larger than previous estimates.

Building upon Milancovic's theory of orbital forcing, this paper reviews the interplay between intrinsic variability and external forcing in the emergence of glacial interglacial cycles. It provides the reader with historical background information and with basic theoretical concepts used in recent paleoclimate research. Moreover, it presents new results which confirm the reduced stability of glacial-cycle dynamics after the mid-Pleistocene transition.

In this study a set of simulations are performed with the regional climate model COSMO-CLM for Europe, for the mid-Holocene and pre-industrial periods. The main aim is to better understand the drivers of differences between models and pollen-based summer temperatures. Results show that a fundamental role is played by spring soil moisture availability. Additionally, results suggest that model bias is not stationary, and an optimal configuration could not be the best under different forcing.

Global mean surface temperatures are rising to levels unprecedented in over 100 000 years. This conclusion takes into account both recent global warming and likely future warming, which thereby enables a direct comparison with paleotemperature reconstructions on multi-century timescales.

Floods in Europe vary on time scales of several decades. Flood-rich and flood-poor periods alternate. Recently floods have again become more frequent. Long time series of peak stream flow, precipitation, and atmospheric variables reveal that until around 1980, these changes were mostly due to changes in atmospheric circulation. However, in recent decades the role of increasing atmospheric moisture due to climate warming has become more important and is now the main driver of flood changes.

The paper deals with 520-year series (1501–2020 CE) of temperature, precipitation, and four drought indices reconstructed from documentary evidence and instrumental observations for the Czech Lands. Basic features of their fluctuations, long-term trends, and periodicities as well as attribution to changes in external forcings and climate variability modes are analysed. Representativeness of Czech reconstructions at European scale is evaluated. The paper shows extreme character of past decades.

A hypothesized link between Pliocene (5.3–2.5 million years ago) global climate and tropical thermocline depth is currently only backed up by data from the Pacific Ocean. In our paper, we present temperature, salinity, and thermocline records from the tropical Atlantic Ocean. Surprisingly, the Pliocene thermocline evolution was remarkably different in the Atlantic and Pacific. We need to reevaluate the mechanisms that drive thermocline depth, and how these are tied to global climate change.