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Ice volume during the last ten 100 ka glacial cycles was driven by solar radiation flux in the Northern Hemisphere. Early minima in solar radiation combined with critical levels of atmospheric CO2 drove initial glacier expansion. Glacial cycles between Marine Isotope Stage (MIS) 24 and MIS 13, whilst at 100 ka periodicity, were irregular in amplitude, and the shift to the largest amplitude 100 ka glacial cycles occurred after MIS 16. Mountain glaciers in the mid-latitudes and Asia reached their maximum extents early in glacial cycles, then retreated as global climate became increasingly arid. In contrast, larger ice masses close to maritime moisture sources continued to build up and dominated global glacial maxima reflected in marine isotope and sea-level records. The effect of this pattern of glaciation on the state of the global atmosphere is evident in dust records from Antarctic ice cores, where pronounced double peaks in dust flux occur in all of the last eight glacial cycles. Glacier growth is strongly modulated by variations in solar radiation, especially in glacial inceptions. This external control accounts for ~50–60% of ice volume change through glacial cycles. Internal global glacier–climate dynamics account for the rest of the change, which is controlled by the geographic distributions of glaciers.

Our understanding of how global climatic changes are translated into ice-sheet fluctuations and sea-level change is currently limited by a lack of knowledge of the configuration of ice sheets prior to the Last Glacial Maximum (LGM). Here, we compile a synthesis of empirical data and numerical modelling results related to pre-LGM ice sheets to produce new hypotheses regarding their extent in the Northern Hemisphere (NH) at 17 time-slices that span the Quaternary. Our reconstructions illustrate pronounced ice-sheet asymmetry within the last glacial cycle and significant variations in ice-marginal positions between older glacial cycles. We find support for a significant reduction in the extent of the Laurentide Ice Sheet (LIS) during MIS 3, implying that global sea levels may have been 30–40 m higher than most previous estimates. Our ice-sheet reconstructions illustrate the current state-of-the-art knowledge of pre-LGM ice sheets and provide a conceptual framework to interpret NH landscape evolution. How global climatic changes are translated into ice-sheet fluctuations and sea-level change is not well understood. Here the authors present a compilation of empirical data and numerical modelling results of pre-LGM Northern Hemisphere ice sheet changes and show pronounced ice-sheet asymmetry within the last glacial cycle and significant variations in ice-marginal positions between older glacial cycles.

Global glaciations have varied in size and magnitude since the Early–Middle Pleistocene transition (~773 ka), despite the apparent regular and high-amplitude 100 ka pacing of glacial–interglacial cycles recorded in marine isotope records. The evidence on land indicates that patterns of glaciation varied dramatically between different glacial–interglacial cycles. For example, Marine Isotope Stages (MIS) 8, 10, and 14 are all noticeably absent from many terrestrial glacial records in North America and Europe. However, globally, the patterns are more complicated, with major glaciations recorded in MIS 8 in Asia and in parts of the Southern Hemisphere, such as Patagonia, for example. This spatial variability in glaciation between glacial–interglacial cycles is likely to be driven by ice volume changes in the West Antarctic Ice Sheet and associated interhemispheric connections through ocean–atmosphere circulatory changes. The weak global glacial imprint in some glacial–interglacial cycles is related to the pattern of global ice buildup. This is caused by feedback mechanisms within glacial systems themselves that partly result from long-term orbital changes driven by eccentricity.

Letter to the Editor

The Dniester valley is a spectacular example of a degrading bedrock fluvial system at the contact between the East European platform and the Carpathian orogen. This study is based upon a combined lithofacies–architecture–morphological study. The complex approach replaces an erstwhile conventional pure geomorphological one, eliminating the shortcomings and inaccuracies, providing a more justified stratigraphy and extended version of the valley evolution. The history of the valley and associated fluvial systems (alluvial fans, delta, coastal alluvial plains) occurred at the end of the Miocene and continued through the Pliocene-Quaternary (11–12 Myr). It unfolded against the background of the retreat of the Eastern Paratethys sea, including the ‘foreland’ and ‘cratonic’ periods and their seven stages. The spatial organization of the river’s drainage networks, sedimentary environments, fluvial styles and landforms changed gradually during these intervals and experienced rapid reorganization when they were replaced. All this left characteristic features within the valley’s four established plain reaches. The tectonic control on these changes through flexural deformation and accelerated uplift/tilt within the platform was decisive while the impact of climatic changes remained problematic. The issues of the river terraces correlation, base-level oscillations, influence of the rock’s erodibility and non-fluvial processes are also considered.

This book provides a new look at the climatic history of the last 2.6 million years during the ice age, a time of extreme climatic fluctuations that have not yet ended. This period also coincides with important phases of human development from Neanderthals to modern humans, both of whom existed side by side during the last cold stage of the ice age. The ice age has seen dramatic expansions of glaciers and ice sheets, although this has been interspersed with relatively short warmer intervals like the one we live in today. The book focuses on the changing state of these glaciers and the effects of associated climate changes on a wide variety of environments (including mountains, rivers, deserts, oceans and seas) and also plants and animals. For example, at times the Sahara was green and colonized by humans, and Lake Chad covered 350,000 km2 – larger than the United Kingdom. What happened during the ice age can only be reconstructed from the traces that are left in the ground. The work of the geoscientist is similar to that of a detective who has to reconstruct the sequence of events from circumstantial evidence. The book draws on the specialisms and experience of the authors who are experts on the glacial history of the Earth. Readership: Undergraduate and postgraduate students studying the Quaternary,  researchers, and anyone interested in climate change, environmental change and geology. The book provides a rich collection of illustrations and photographs to help the readers at all levels visualise the dramatic consequences of glacier expansions during the Ice Age.  

Following the recent rejection of a formal Anthropocene series/epoch by the Subcommission on Quaternary Stratigraphy (SQS) of the International Commission on Stratigraphy (ICS), and its subsequent confirmation by the International Union of Geological Sciences (IUGS), the opportunity arises to reset the definition of the Anthropocene. The case for informally recognizing the Anthropocene to be a major planetary event of Earth system transformation offers a promising way forward, but this has been criticized by proponents of an Anthropocene series/epoch. In order to move on from the assumption that it must be a time interval, and to foster a more transdisciplinary and inclusive approach, the main points of the critique must be directly addressed. Plain Language Summary The Anthropocene is best understood as an unfolding and intensifying event of human‐influenced Earth system change. Here we respond to criticisms of the case for the Anthropocene Event and explain why attention should be shifted away from the narrow question of date of start which has dominated debate up to now. The Anthropocene, we argue, is more than just a time interval. It is first and foremost a material happening or physical transformation which unfolds through time. Interdisciplinary research on the Anthropocene is more important than ever and must continue apace. Key Points The Anthropocene is best studied as an ongoing event of human‐influenced planetary transformation rather than a time interval The Great Acceleration is an intensification of a larger unfolding Anthropocene Event that is spatially and temporally heterogeneous Interdisciplinary research on the Anthropocene is now more important than ever

The penultimate deglaciation (PDG, ∼138–128 thousand years before present, hereafter ka) is the transition from the penultimate glacial maximum (PGM) to the Last Interglacial (LIG, ∼129–116 ka). The LIG stands out as one of the warmest interglacials of the last 800 000 years (hereafter kyr), with high-latitude temperature warmer than today and global sea level likely higher by at least 6 m. Considering the transient nature of the Earth system, the LIG climate and ice-sheet evolution were certainly influenced by the changes occurring during the penultimate deglaciation. It is thus important to investigate, with coupled atmosphere–ocean general circulation models (AOGCMs), the climate and environmental response to the large changes in boundary conditions (i.e. orbital configuration, atmospheric greenhouse gas concentrations, ice-sheet geometry and associated meltwater fluxes) occurring during the penultimate deglaciation.A deglaciation working group has recently been set up as part of the Paleoclimate Modelling Intercomparison Project (PMIP) phase 4, with a protocol to perform transient simulations of the last deglaciation (19–11 ka; although the protocol covers 26–0 ka). Similar to the last deglaciation, the disintegration of continental ice sheets during the penultimate deglaciation led to significant changes in the oceanic circulation during Heinrich Stadial 11 (∼136–129 ka). However, the two deglaciations bear significant differences in magnitude and temporal evolution of climate and environmental changes.Here, as part of the Past Global Changes (PAGES)-PMIP working group on Quaternary interglacials (QUIGS), we propose a protocol to perform transient simulations of the penultimate deglaciation under the auspices of PMIP4. This design includes time-varying changes in orbital forcing, greenhouse gas concentrations, continental ice sheets as well as freshwater input from the disintegration of continental ice sheets. This experiment is designed for AOGCMs to assess the coupled response of the climate system to all forcings. Additional sensitivity experiments are proposed to evaluate the response to each forcing. Finally, a selection of paleo-records representing different parts of the climate system is presented, providing an appropriate benchmark for upcoming model–data comparisons across the penultimate deglaciation.