The biodiversity of temperate deciduous trees in eastern Asia is greater than in Europe. During the peak of the last ice age, their distribution was obtained based on pollen data literature. A climate model, after validation on the present, was used to calculate the potential distribution of such trees in the past. It shows that the shift of the tree belt was only 2° latitude to the south. Moreover, greater population connectivity was shown for the Yellow Sea and southern Himalayas.

This work presents the observation of the Early Jurassic terrestrial climate from the Sichuan paleobasin, southeastern China. Results manifest a (semi)arid climate in the study area, where the climate pattern is similar to the Colorado Plateau. The estimated atmospheric carbon dioxide concentration is 980–2610 ppmV with a mean of 1660 ppmV. The change of carbon dioxide concentration is compatible with the excursions of stable isotopes and seawater temperature from the coeval marine sediments.

A new approach to reconstruct the temporal variation of rock surface temperature using the thermoluminescence (TL) of feldspar is introduced. Multiple TL signals or thermometers in the range of 210 to 250 °C are sensitive to typical surface temperature fluctuations and can be used to constrain thermal histories of rocks over ~50 kyr. We show that it is possible to recover thermal histories of rocks using inverse modeling and with δ18O anomalies as a priori information.

The large-scale features of middle Pliocene climate from the 16 models of PlioMIP Phase 2 are presented. The PlioMIP2 ensemble average was ~ 3.2 °C warmer and experienced ~ 7 % more precipitation than the pre-industrial era, although there are large regional variations. PlioMIP2 broadly agrees with a new proxy dataset of Pliocene sea surface temperatures. Combining PlioMIP2 and proxy data suggests that a doubling of atmospheric CO₂ would increase globally averaged temperature by 2.6–4.8 °C.

Previous studies related to historical droughts in the Czech Lands showed that the summers of 1531–1540 could represent the driest summer decade of the past 500 years. To confirm this hypothesis, documentary data from central Europe were collected and presented for individual summers and complemented by maps of precipitation and drought distribution to document corresponding weather patterns and their various impacts. The main droughts occurred in 1532, 1534–1536, 1538, and particularly in 1540.

In general, it is not easy to reconstruct past climate variations over a wide band of frequencies using a single proxy. Here, we propose a new method to reconstruct past summer climate seamlessly from annual to millennial timescales by integrating tree-ring cellulose oxygen and hydrogen isotope ratios. The result can be utilized to investigate various scales of climatological phenomena in the past and climate–society relationships in long human history.

Droughts derive from a precipitation deficit and belong to the most dangerous natural hazards for human societies. Documentary data of the pre-modern and early modern times contain direct and indirect information on precipitation that allows for the production of reconstructions using historical climatology methods. For this study, two drought indices were created on the basis of documentary data produced in Bern, Switzerland, and Rouen, France, for the period from 1315 to 1715.

Our study is the first study to conduct transient simulations over MIS 7, using a 3-D coupled climate–ice sheet model with interactive ice sheets in both hemispheres. We find glacial inceptions to be more sensitive to orbital variations, whereas glacial terminations need the concerted action of both orbital and CO₂ forcings. We highlight the issue of multiple equilibria and an instability due to stationary-wave–topography feedback that can trigger unrealistic North American ice sheet growth.

We reconstruct atmospheric CO₂ from the EPICA Dome C ice core during Marine Isotope Stage 6 (185–135 ka) to understand carbon mechanisms under the different boundary conditions of the climate system. The amplitude of CO₂ is highly determined by the Northern Hemisphere stadial duration. Carbon dioxide maxima show different lags with respect to the corresponding abrupt CH₄ jumps, the latter reflecting rapid warming in the Northern Hemisphere.

Proxy data of sediment cores, speleothem, pollen and isotope data were used to reconstruct past aridity of eight regions of the world over the last 60 000 years. These regions show humid conditions during the early MIS3 (60 to 45 ka). Also the early Holocene (14 to 6 ka) was humid throughout the regions. In contrast, MIS2 and the LGM were arid in Northern Nemisphere records. On- and offsets of aridity/humidity differ between the regions. All this is in good agreement with recent model results.

Monsoons and westerly winds interact with each other in the middle to low latitudes. We track millennial-scale evolution characteristics of monsoons and westerly winds over the past 21 000 years. In the monsoon-dominated regions of Asia, a humid climate prevails in the past 6000–10 000 years, while in the westerly-wind-dominated regions of Asia, the climate is relatively humid around 21 000 years and 6000 years ago.

Fossil pollen and spores reveal that a strongly seasonal steppe–desert ecosystem existed in the Nangqian Basin, east-central Tibet during the late Eocene (41.2–37.8 Ma). Vegetation was characterized by drought-tolerant shrubs, diverse ferns, and broad-leaved forests. The climate warmed temporarily, then rapidly aridified thereafter due to westward regression of the proto-Paratethys Sea from Eurasia. Sea retreat was a main driver of widespread long-term Asian aridification during the late Eocene.

Future climate is expected to be warmer than today. We study climate based on simulations of the mid-Pliocene (about 3 million years ago), which was a time of elevated temperatures, and discuss implications for the future. Our results are provided towards a comparison to both proxy evidence and output of other climate models. We simulate a mid-Pliocene climate that is both warmer and wetter than today. Some climate characteristics can be more directly transferred to the near future than others.

The simulations for the past climate can inform us about the performance of climate models in different climate scenarios. Here, we analyse Arctic warming in an ensemble of 16 simulations of the mid-Pliocene Warm Period (mPWP), when the CO₂ level was comparable to today. The results highlight the importance of slow feedbacks in the model simulations and imply that we must be careful when using simulations of the mPWP as an analogue for future climate change.

The onset of Little Ice Age cooling around 1310 CE was preceded in Europe by a series of droughts in the first decade of the 14th century that were uniquely severe in the period 1200–1400. Based mainly on information from chronicles and other historical texts, we reconstructed the socioeconomic and cultural impact of these events but also a seesaw pattern of multiannual droughts in the Mediterranean and Europe north of the Alps that has remarkable resemblances to the 2018–2019 dry period.

We present a first chronology for the East Greenland Ice-core Project (EGRIP) over the Holocene and last glacial termination. After field measurements and processing of the ice-core data, the GICC05 timescale is transferred from the NGRIP core to the EGRIP core by means of matching volcanic events and common patterns (381 match points) in the ECM and DEP records. The new timescale is named GICC05-EGRIP-1 and extends back to around 15 kyr b2k.

We revisit 15-year-old reconstructions of sea surface temperatures in the Arctic Ocean for the late Paleocene and early Eocene epochs (∼ 57–53 million years ago) based on the distribution of fossil membrane lipids of archaea preserved in Arctic Ocean sediments. We find that improvements in the methods over the past 15 years do not lead to different results. However, data quality is now higher and potential biases better characterized. Results confirm remarkable Arctic warmth during this time.

The compositions of foraminifera shells often vary with environmental parameters such as temperature or salinity; thus, they can be used as proxies for these environmental variables. Often a single proxy is influenced by more than one parameter. Here, we show that while salinity impacts shell Na / Ca, temperature has no effect. We also show that the combination of different proxies (Mg / Ca and δ¹⁸O) to reconstruct salinity does not seem to work as previously thought.

Radiolarians are marine micro-organisms that produce a siliceous shell that is preserved in the fossil record and can be used to reconstruct past climate variability. However, their study is only possible after a time-consuming manual selection of their shells from the sediment followed by their individual identification. Thus, we develop a new fully automated workflow consisting of microscopic radiolarian image acquisition, image processing and identification using artificial intelligence.

A new ice core drilled at the South Pole provides a 54 000-year paleo-environmental record including the composition of the past atmosphere. This paper describes the gas chronology for the South Pole ice core, based on a high-resolution methane record. The new gas chronology, in combination with the existing ice age scale from Winski et al. (2019), allows a model-independent reconstruction of the delta age record.

We present a reconstruction of summer temperature for the last millennium in east-central Europe that shows little summer temperature differences between the Medieval Warm Period and the Little Ice Age on centennial scales as well as the fact that well-expressed minima and maxima occurred synchronously with periods of low and high solar activity, respectively. Furthermore, summer temperatures fluctuated with a periodicity similar to that of the Atlantic Multidecadal Oscillation.

We tested the applicability of the organic biomarker IPSO₂₅ for sea ice reconstructions in the industrial era at the western Antarctic Peninsula. We successfully evaluated our data with satellite sea ice observations. The comparison with marine and ice core records revealed that sea ice interpretations must consider climatic and sea ice dynamics. Sea ice biomarker production is mainly influenced by the Southern Annular Mode, while the El Niño–Southern Oscillation seems to have a minor impact.

In this study, we present pollen and grain size data obtained from the Bohai Sea. The results reveal that soil development and salinity gradients are the main factors determining the vegetation dynamics of coastal wetland. Moreover, our pollen-based temperature index revealed a warm Early Holocene, a cool Middle Holocene and then a relatively warm Late Holocene. The main driving factors of temperature variation in this region are insolation, greenhouse gases and ENSO.

Over the past 20 Myr, there has been a dramatic global increase in plants using C₄ photosynthetic pathways. We analyze C and H isotopes in fatty acids of leaf waxes preserved in marine sediment from the Bay of Bengal to examine changes in photosynthesis in the Core Monsoon Zone of the Indian Peninsula over the past 6 Myr. The observed increase in C₄ vegetation from 3.5 to 1.5 Ma is synchronous with C₄ expansions in northwest Australia and East Africa, suggesting regional hydroclimate controls

The dating technique of ¹⁴C plateau tuning uses U/Th-based model ages, refinements of the Lake Suigetsu age scale, and the link of surface ocean carbon to the globally mixed atmosphere as basis of age correlation. Our synthesis employs data of 20 sediment cores from the global ocean and offers a coherent picture of global ocean circulation evolving over glacial-to-deglacial times on semi-millennial scales to be compared with climate records stored in marine sediments, ice cores, and speleothems.

Warm climates of the deep past have proven to be challenging to reconstruct with the same numerical models used for future predictions. We present results of CESM simulations for the middle to late Eocene (∼ 38 Ma), in which we managed to match the available indications of temperature well. With these results we can now look into regional features and the response to external changes to ultimately better understand the climate when it is in such a warm state.

We explore the utiliity of the composition of fossil lipid biomarkers, which are commonly preserved in ancient marine sediments, in providing estimates of past ocean temperatures. The group of lipids concerned show compositional changes across the modern oceans that are correlated, to some extent, with local surface ocean temperatures. Here we present new machine learning approaches to improve our understanding of this temperature sensitivity and its application to reconstructing past climates.