Rather than reverting to a dedicated paleoclimate chapter, knowledge about pre-industrial climate should be further integrated with other lines of evidence throughout the next assessment reports by the Intergovernmental Panel on Climate Change.

Desert dust plays a crucial role in the climate system; while it is relatively well studied for the present day, we still lack knowledge on how it was in the past and on its underlying mechanism in the multi-million-year timescale of Earth’s history. For the first time, we simulate dust emissions using the newly developed DUSTY1.0 model over the past 540 million years with a temporal resolution of ~5 million years. We find that palaeogeography is the primary control of these variations.

Antarctic ice cores provide information about past temperatures. Here, we run new climate model simulations, including stable water isotopes for the historical period. Across one-third of Antarctica, there is no strong connection between isotopes and temperature and a weak connection for most of the rest of Antarctica. This disconnect between isotopes and temperature is largely driven by changes in Antarctic sea ice. Our results are helpful for temperature reconstructions from ice core records.

We use existing palaeoclimate data and a statistical model to predict atmospheric CO₂ concentrations across the Mid-Pleistocene Transition. Our prediction assumes that the relationship between CO₂ and benthic ẟ¹⁸O_calcite over the past 800 000 years can be extended over the last 1.8 million years. We find no clear evidence from existing blue ice or proxy-based CO₂ data to reject the predicted record. A definitive test awaits analysis of continuous oldest ice core records from Antarctica.

The chemical records contained in a 12 m firn (ice) core from Peter I Island, a remote sub-Antarctic island situated in the Pacific sector of the Southern Ocean (the Bellingshausen Sea), capture changes in snowfall and temperature (2002–2017 CE). This data-sparse region has experienced dramatic climate change in recent decades, including sea ice decline and ice loss from adjacent West Antarctic glaciers. 

The ice-rafted debris signature of Heinrich events in marine sedimentary cores is usually attributed to massive ice discharge from the Laurentide Ice Sheet. However, the driving mechanism of this pulsed discharge remains  unclear. We compare three previously proposed hypotheses and examine the role of relevant system processes. We find ice stream surge cycling is the most likely mechanism, but its character is sensitive to both the geothermal heat flux and the form of the basal drag law.

The Indo-Pacific Pollen Database is a large collection of pollen samples from across the Indo-Pacific region, with most samples coming from Australia. This is a valuable collection that can be used to analyse vegetation dynamics going back thousands of years. It is now being fully shared via Neotoma for the first time, opening up many exciting new avenues of research. This paper presents key aspects of this database, including geographical distribution, age control and deposition times.

Our study collected 63 historical documents on the extreme heat of 1743 from three kinds of historical materials. Using text analysis methods, such as keyword extraction, grading, and classification, we reconstructed the 1743 extreme heat event. This heat event developed cumulatively, and the key areas affected are consistent with those impacted in modern times. Timely cooling and reducing exposure have been limited but necessary means of addressing extreme heat in both ancient and modern times.

Dansgaard–Oeschger events are a series of abrupt past climate change events during which the atmosphere, sea ice, and ocean in the North Atlantic underwent rapid changes. One current topic of interest is the order in which these different changes occurred, which remains unknown. In this work, we find that the current best method used to investigate this topic is subject to substantial bias. This implies that it is not possible to reliably determine the order of the different changes.

The simultaneity of rain and heat is an important hypothesis containing the summer and winter precipitation regimes. In this paper, eastern and part of central Asia (EA and CA) with a summer precipitation regime are selected to study the dry/wet status on multiple timescales since the Last Glacial Maximum. We found that although climate difference in EA and CA universally exists, climate linkages in EA and part of CA with a summer precipitation regime can be uncovered.

Clarifying the paleoelevation changes of Diancang Shan (DCS) is important for comprehending both tectonics and the climatic effects in the transition zone between the high Tibetan Plateau and the lower relief of eastern and southern Asia. Our results show low elevations of DCS between ~ 7.6 and ~ 5.0 Ma, followed by significant uplift of 1000–2000 m between ~ 5.0 and ~ 3.5 Ma. They provide a novel method for reconstructing the paleoelevation of mountains like DCS in orogenic belts.

We develop the Multi Ensemble Machine Learning Model (MEMLM) for reconstructing palaeoenvironments from microfossil assemblages. The machine-learning approaches, which include random tree and natural language processing techniques, substantially outperform classical approaches under cross-validation, but they can fail when applied to reconstruct past environments. Statistical significance testing is found sufficient to identify these unreliable reconstructions.

Studying climate conditions near the Antarctic ice sheet (AIS) during Earth’s past warm periods informs us about how global warming may influence AIS ice loss. Using a global climate model, we investigate climate conditions near the AIS during the Last Interglacial (129 to 116 kyr ago), a period with warmer global temperatures and higher sea level than today. We identify the orbital and freshwater forcings that could cause ice loss and probe the mechanisms that lead to warmer climate conditions.

In our work, we reconstruct the weather of the extremely cold and wet summer in 1816 using a weather forecasting model to obtain high-resolution, three-dimensional weather simulations. We refine our simulations with surface pressure and temperature observations, representing a novel approach for this period. Our results show that this approach yields detailed and accurate weather reconstructions, opening the door to analyzing past weather events and their impacts in detail.

We present simulations of the mid-Holocene and pre-industrial climate of Australia using coarse- (2°) and finer-resolution (0.44°) climate models. These simulations are compared to bioclimatic representations of the palaeoclimate of the mid-Holocene. The finer-resolution simulations reduce the bias between the model and the bioclimatic results and highlight the improved value of using finer-resolution models to simulate the palaeoclimate.

This study used 1802 drought and 1977 famine records from historical documents to reconstruct the spatial–temporal progression of the Chongzhen drought (1627–1644) in China and its impacts. We advance this research by reconstructing the annual spatial patterns and regional series of drought; demonstrating drought as the primary factor triggering famine; and identifying the transmission pathway of the drought's impacts and how social factors, especially human responses, regulated these impacts.

Old observations are necessary to understand the atmosphere. When direct observations are not available, one can use indirect observations, such as tide gauges, which measure the sea level in port cities. The sea level rises when local air pressure decreases and when wind pushes water towards the coast. Several centuries-long tide gauge records are available. We show that these can be complementary to direct pressure observations for studying storms and anticyclones in the 19th century.

The Benguela Upwelling System is a region in the SE Atlantic Ocean of high biological productivity. It comprises several water masses such as the Benguela Current, South Atlantic Central Water, and Indian Ocean Agulhas waters. We analyzed planktonic foraminifera from IODP Sites U1575 and U1576 to characterize water masses and their interplay in the Pleistocene. This defined changes in the local thermocline, which were linked to long-term Benguela Niño- and Niña-like and deglaciation events.

The year 1740 was the coldest in central Europe since at least 1421. New monthly global climate reconstructions, together with daily weather reconstructions, allow a detailed view of this climatic event. Following several severe cold spells in January and February, a persistent circulation pattern with blocking over the British Isles caused northerly flow towards western Europe during a large part of the year. It was one of the strongest, arguably unforced excursions in European temperature.

Simulations of the last two glacial periods are run using a computer model in which the atmosphere and ice sheets interact. The results show that the initial conditions used in the simulations are the primary reason for the difference in simulated North American ice sheet volume between each period. Thus, the climate leading up to the glacial maxima and other factors, such as vegetation, are important contributors to the differences in the ice sheets at the Last and Penultimate glacial maxima.

We reconstruct environmental changes derived from sediments of Schweriner See, a large lake in NE Germany, for the past 3000 years. We infer variations in North Atlantic large-scale atmospheric circulation systems, namely the North Atlantic Oscillation (NAO), by combining sedimentological, geochemical, and biological parameters. Our results suggest distinct shifts between positive and negative NAO phases affecting winter temperatures, precipitation, and westerly wind strength at our study site.

We date sedimentary deposits showing that the southeastern Laurentide Ice Sheet was at or near its southernmost extent from ~ 26 000 to 21 000 years ago, when sea levels were at their lowest, with climate records indicating glacial conditions. Slow deglaciation began ~ 22 000 years ago, shown by a rise in modeled local summer temperatures, but significant deglaciation in the region did not begin until ~ 18 000 years ago, when atmospheric CO₂ began to rise, marking the end of the last ice age.

Past climate reconstructions are essential for understanding climate mechanisms and drivers. Our focus is on the South American continent over the past 2000 years. We offer a new reconstruction that particularly utilizes data from speleothems, previously absent from continent-wide reconstructions. We use paleoclimate data assimilation, a reconstruction method that combines information from climate archives and climate simulations.

Our research discovered significant seasonal temperature variations in the North Atlantic's mid-latitudes during the early Late Pliocene. This highlights the necessity of using multiple methods to get a full picture of past climates, thus avoiding a biased understanding of the climate system. Moreover, our study reveals that the precession signal, which previously dominated surface temperature records, disappeared with the increased influence of the ice sheets in the Northern Hemisphere.