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In response to our definition of the Anthropocene as a geological event analogous to the Great Oxidation Event and other complex, transformative events in the geological record (Gibbard et al., 2022a, 2022b), Waters et al. (2022) offers a suite of detailed and novel terminology for the Anthropocene with little or no previous support in the geological literature. The term “event” is already widely used as a general term in geology. We maintain that the Anthropocene is best understood through this general definition as a complex, heterogenous and ongoing event composed of manifold identifiable events occurring within it.

Constraining the greenhouse gas forcing, climatic warming and estimates of climate sensitivity across ancient large transient warming events is a major challenge to the palaeoclimate research community. Here we provide a new compilation and synthesis of the available marine proxy temperature data across the largest of these hyperthermals, the Paleocene-Eocene Thermal Maximum (PETM). This includes the application of consistent temperature calibrations to all data, including the most recent set of calibrations for archaeal lipid-derived palaeothermometry. This compilation provides the basis for an informed discussion of the likely range of PETM warming, the biases present in the existing record and an initial assessment of the geographical pattern of PETM ocean warming. To aid interpretation of the geographic variability of the proxy-derived estimates of PETM warming, we present a comparison of this data with the patterns of warming produced by high pCO(2) simulations of Eocene climates using the Hadley Centre atmosphere-ocean general circulation model (AOGCM) HadCM3L On the basis of this comparison and taking into account the patterns of intermediate-water warming we estimate that the global mean surface temperature anomaly for the PETM is within the range of 4 to 5 degrees C. (C) 2013 Elsevier B.V. All rights reserved.

The Amazon basin is a major component of the global carbon and hydrological cycles, a significant natural source of methane, and home to remarkable biodiversity and endemism. Reconstructing past climate changes in the Amazon basin is important for a better understanding of the effect of such changes on these critical functions of the basin. Using a novel biomarker proxy, based on the membrane lipids of soil bacteria with a new regional calibration, we present a reconstruction of changes in mean annual air temperatures for the Amazon catchment during the last 37 kyr B. P. Biomarkers were extracted from Ocean Drilling Program sediment core ODP942 recovered from the Amazon fan. The Amazon fan is a major depository for terrestrial sediments, with the advantage that the terrestrial material captured reflects a regional integration of the whole river catchment. The reconstructed tropical Amazonian temperatures were similar to 5 degrees C cooler at the Last Glacial Maximum (similar to 21 degrees C) compared to modern values (similar to 26 degrees C). This is in agreement with previous estimates of tropical continental temperatures in the tropical Amazon basin and tropical Africa during the Last Glacial Maximum. Moreover, we also illustrate how the soil bacterial membrane lipid record reveals major changes in basin dynamics and sediment provenance during the glacial-Holocene transition, impacting the biomarker reconstructions from similar to 11 kyr onward.

Establishing a time frame for the development of the modern halocline and stratified water column in the subarctic North Pacific has significant paleoclimatic implications. Here we present a δ18O(diatom) record consisting of only two species that represents autumn/winter conditions in the region across the onset of major Northern Hemisphere glaciation boundary. At circa 2.73 Ma a decrease in δ18O(diatom) of 4.6‰ occurs, whereas previously published δ18O(foram) results show a 2.6‰ increase. The δ18O(diatom) and U37 k sea surface reconstructions indicate both a significant freshening of 2–4 practical salinity units and an increase in surface temperatures in the summer to early winter period from circa 2.73 Ma onward. In contrast, the concomitant increase in δ18O(foram) is likely to be reflective of conditions beneath the mesothermal structure and/or spring conditions when warmer sea surface temperatures are not present in the region. These results are consistent with the development of the modern halocline system at 2.73 Ma with year-round stratification of the water column and a strengthened seasonal thermocline during the summer to early winter period, resulting in one of the largest summer to winter temperature gradients in the open ocean. The onset of stratification would also have led to a warm pool of surface water from circa 2.73 Ma, which may have provided a potential source of extra moisture needed to supply the growing North American ice sheets at this time.

This is the River Dart Fisheries Survey 1974 report produced by the South West Water Authority. The survey was carried out between July and October 1974 to assess the extent of the 0+ and 1+ Salmo salar L. population in the Dart catchment and thereby assess directly the success of the 1973/74 and 1972/73 spawning season. The survey showed that there were large numbers of salmon parr distributed throughout the upper reaches of the Dart, reflecting the successful spawning of the 1973/74 and 1972/73 season. It contains tables with survey sections locations, presence/absence for each section and location maps with spawning grounds and sampling stations. Environment Agency Archives South West

This is the River Dart, Spawning 1992 report produced by the National Rivers Authority. It contains details on the hydrological conditions and redd sighting locations on the River Dart, as well as kelts presence data. It also contains two basic diagrams showing the location of the sightings. Environment Agency Archives South West

This is the River Dart, Weir and Fish Pass Survey 1992 report produced by the National Rivers Authority.It goes through the general condition of Weirs and fish passes to determine the extent of problems associated with the upstream and downstream migration of salmonids. It considers solutions where problems exist and investigates the exact use of the resource. It looks at the following Weirs: Totnes, Staverton, Hood, Kilbury, Buckfast, Holne, Mardle (River Mardle), Holybrook (Holybrook), Jordan (West Webburn), Swincombe Intake (River Swincombe), Blackbrook, West Dart, Cowsic (Devonport Leat), Kingfisher Press (Bidwell Brook) and Bagpark (East Webburn). It also contains location maps of the weirs and individual fact sheets along detailed pictures and diagrams. Environment Agency Archives South West

We examine the effect on atmospheric CO2 of the occurrence of increased shallow water carbonate deposition and regrowth of the terrestrial biosphere following the last glacial. We find that contrary to recent speculations that changes in terrestrial carbon storage were primarily responsible for the observed similar to20 ppmv late Holocene CO2 rise, a more likely explanation is coral reef buildup and other forms of shallow water carbonate deposition during this time. The importance of a responsive terrestrial carbon reservoir may instead be as a negative feedback restricting the rate of CO2 rise possible in the early stages of the deglacial transition. This separation in time of the primary impacts of regrowth of the terrestrial biosphere and increased shallow water carbonate deposition explains the occurrence of an early Holocene carbonate preservation event observed in deep-sea sediments. We demonstrate that their combined influence is also consistent with available proxy estimates of deep ocean carbonate ion concentration changes over the last 21 kyr. Accounting for the processes that act on the carbonate chemistry of the ocean as a whole then allows us to place strong constraints on the nature of the remaining processes that must be operating at the deglacial transition. By subtracting the net CO2 effect of coral reef buildup and terrestrial biosphere regrowth from recent high-resolution ice core data, we highlight two periods, from 17.0 to 13.8 kyr and 12.3 to 11.2 kyr BP characterized by sustained rapid rates of CO2 increase (> 12 ppmv kyr(-1)). Because these periods are coincident with Southern Hemisphere "deglaciation,'' we argue that changes in the biogeochemical properties of the Southern Ocean surface are the most likely cause.

We present new high‐resolution pollen records combined with palaeoceanographic proxies from the same samples in deep‐sea cores SHAK06‐5K and MD01‐2444 on the southwestern Iberian Margin, documenting regional vegetation responses to orbital and millennial‐scale climate changes over the last 28 ka. The chronology of these records is based on high‐resolution radiocarbon dates of monospecific samples of the planktonic foraminifera Globigerina bulloides, measured from SHAK06‐5K and MD01‐2444 and aligned using an automated stratigraphical alignment method. Changes in temperate and steppe vegetation during Marine Isotope Stage 2 are closely coupled with sea surface temperature (SST) and global ice‐volume changes. The peak expansion of thermophilous woodland between ~10.1 and 8.4 cal ka bp lags behind the boreal summer insolation maximum by ~2 ka, possibly arising from residual high‐latitude ice‐sheets into the Holocene. Rapid changes in pollen percentages are coeval with abrupt transitions in SSTs, precipitation and winter temperature at the onset and end of Heinrich Stadial 2, the ice‐rafted debris event and end of Heinrich Stadial 1, and the onset of the Younger Dryas, suggesting extrinsically forced southwestern Iberian ecosystem changes by abrupt North Atlantic climate events. In contrast, the abrupt decline in thermophilous elements at ~7.8 cal ka bp indicates an intrinsically mediated abrupt vegetation response to the gradually declining boreal insolation, potentially resulting from the crossing of a seasonality of precipitation threshold.

The response of the tropical ocean to global climate change and the extent of sea ice in the glacial nordic seas belong to the great controversies in paleoclimatology. Our new reconstruction of peak glacial sea surface temperatures (SSTs) in the Atlantic is based on census counts of planktic foraminifera, using the Maximum Similarity Technique Version 28 (SIMMAX-28) modern analog technique with 947 modern analog samples and 119 well-dated sediment cores. Our study compares two slightly different scenarios of the Last Glacial Maximum (LGM), the Environmental Processes of the Ice Age: Land, Oceans, Glaciers (EPILOG), and Glacial Atlantic Ocean Mapping (GLAMAP 2000) time slices. The comparison shows that the maximum LGM cooling in the Southern Hemisphere slightly preceeded that in the north. In both time slices sea ice was restricted to the north western margin of the nordic seas during glacial northern summer, while the central and eastern parts were ice-free. During northern glacial winter, sea ice advanced to the south of Iceland and Faeroe. In the central northern North Atlantic an anticyclonic gyre formed between 45degrees and 60degreesN, with a cool water mass centered west of Ireland, where glacial cooling reached a maximum of >12degreesC. In the subtropical ocean gyres the new reconstruction supports the glacial-to-interglacial stability of SST as shown by CLIMAP Project Members (CLIMAP) [1981]. The zonal belt of minimum SST seasonality between 2degrees and 6degreesN suggests that the LGM caloric equator occupied the same latitude as today. In contrast to the CLIMAP reconstruction, the glacial cooling of the tropical east Atlantic upwelling belt reached up to 6degrees-8degreesC during Northern Hemisphere summer. Differences between these SIMMAX-based and published U37(k)- and Mg/Ca-based equatorial SST records are ascribed to strong SST seasonalities and SST signals that were produced by different planktic species groups during different seasons.

Ice retreat on volcanoes reduces pressure at the surface of the Earth and induces stress changes in magmatic systems. The consequences can include increased generation of magma at depth, increased magma capture in the crust, and modification of failure conditions of magma chambers. We review the methodology to evaluate each of these effects, and consider the influence of ongoing ice retreat on volcanoes at the Mid-Atlantic divergent plate boundary in Iceland. Evaluation of each of these effects requires a series of assumptions regarding the rheology of the crust and mantle, and the nature of magmatic systems, contributing to relatively large uncertainty in response of a magmatic system to climate warming and associated ice retreat. Pressure release melting due to ice cap retreat in Iceland may at present times generate a similar amount of magma as plate tectonic processes; larger than realized previously. However, new modelling shows that part of this magma may be captured in the crust, rather than being erupted. Gradual retreat of ice caps do steadily modify failure conditions at magma chambers, which is highly dependent on their geometry and depth, as well as the details of ice load variations. A model is presented where long-term ice retreat at Katla volcano decreases the likelihood of eruption, as more magma is needed in the magma chamber to cause failure than in the absence of the ice retreat.