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The Peach Slide is the largest known submarine mass movement on the British continental margin and is situated on the northern flank of the glacigenic Barra Fan. The Barra Fan is located on the northwest British continental margin and is subject to cyclonic ocean circulation, with distinct differences between the circulation during stadial and inter-stadial periods. The fan has experienced growth since continental uplift during the mid-Pliocene, with the majority of sediments deposited during the Pleistocene when the fan was a major depocentre for the British-Irish Ice Sheet (BIIS). Surface and shallow sub-surface morphology of the fan has been mapped using newly digitised archival paper pinger and deep towed boomer sub-bottom profile records, side scan sonar and multibeam echosounder data. This process has allowed the interpretation and mapping of a number of different seismic facies, including: contourites, hemipelagites and debrites. Development of a radiocarbon based age model for the seismic stratigraphy constrains the occurrence of two periods of slope failure: the first at circa 21 ka cal BP, shortly after the BIIS's maximum advance during the deglaciation of the Hebrides Ice Stream; and the second between 12 and 11 ka cal BP at the termination of the Younger Dryas stadial. Comparison with other mass movement events, which have similar geological and oceanographic settings, suggests that important roles are played by contouritic and glacigenic sedimentation, deposited in inter-stadial and stadial periods respectively when different thermohaline regimes and sediment sources dominate. The effect of this switch in sedimentation is to rapidly deposit thick, low permeability, glacigenic layers above contourite and hemipelagite units. This process potentially produced excess pore pressure in the fan sediments and would have increased the likelihood of sediment failure via reduced shear strength and potential liquefaction. [ABSTRACT FROM AUTHOR]

The Early Middle Pleistocene Transition (EMPT) is the term used to describe the prolongation and intensification of glacial–interglacial climate cycles that initiated after 900,000 years ago. During the transition glacial–interglacial cycles shift from lasting 41,000 years to an average of 100,000 years. The structure of these glacial–interglacial cycles shifts from smooth to more abrupt ‘saw-toothed’ like transitions. Despite eccentricity having by far the weakest influence on insolation received at the Earth's surface of any of the orbital parameters; it is often assumed to be the primary driver of the post-EMPT 100,000 years climate cycles because of the similarity in duration. The traditional solution to this is to call for a highly nonlinear response by the global climate system to eccentricity. This ‘eccentricity myth’ is due to an artefact of spectral analysis which means that the last 8 glacial–interglacial average out at about 100,000 years in length despite ranging from 80,000 to 120,000 years. With the realisation that eccentricity is not the major driving force a debate has emerged as to whether precession or obliquity controlled the timing of the most recent glacial–interglacial cycles. Some argue that post-EMPT deglaciations occurred every four or five precessional cycle while others argue it is every second or third obliquity cycle. We review these current theories and suggest that though phase-locking between orbital forcing and global ice volume may occur the chaotic nature of the climate system response means the relationship is not consistent through the last 900,000 years. [ABSTRACT FROM AUTHOR]

Marine seismic reflection data have been collected for decades and since the mid-to late- 1980s much of this data is positioned relatively accurately. This older data provides a valuable archive, however, it is mainly stored on paper records that do not allow easy integration with other datasets. A method for converting these records to digital SEGY format has been reported previously, although the accuracy and reliability has not been documented. Using 3.5 kHz pinger, bathymetric and side scan sonar data we test the accuracy and data resolution of converted paper seismic records on the surface and shallow-subsurface of the Barra Fan, NE Atlantic Ocean. Frequencies of navigational updates and printed fix marks are vital in determining positional accuracy as interpolation between fixes, which may be 30 minutes apart, is a significant source of potential error. Vertical data resolution of the converted records is primarily governed by the dimensions of the printed record, with order of magnitude differences noted between the scanned BGS and NOC pinger records. Positional accuracy of pinger data is observed to be within the resolution of the bathymetric grid. BGS 1985 pinger data is located within 40 m of bathymetric constrained locations at 635 m below mean sea level and NOC 1998 pinger data within 25 m of bathymetric locations at 1180 m below mean sea level. This paper-to-digital conversion is not a replacement for modern data acquisition, but it does provide a valuable complement to such data. Where appropriate archival paper data is available for conversion it could be used to assist efficiency of forthcoming surveys and may be used to provide time series evidence of seabed processes. [ABSTRACT FROM AUTHOR]

Current evidence suggests that all of the major events in hominin evolution have occurred in East Africa. Over the last two decades, there has been intensive work undertaken to understand African palaeoclimate and tectonics in order to put together a coherent picture of how the environment of East Africa has varied in the past. The landscape of East Africa has altered dramatically over the last 10 million years. It has changed from a relatively flat, homogenous region covered with mixed tropical forest, to a varied and heterogeneous environment, with mountains over 4 km high and vegetation ranging from desert to cloud forest. The progressive rifting of East Africa has also generated numerous lake basins, which are highly sensitive to changes in the local precipitation-evaporation regime. There is now evidence that the presence of precession-driven, ephemeral deep-water lakes in East Africa were concurrent with major events in hominin evolution. It seems the unusual geology and climate of East Africa created periods of highly variable local climate, which, it has been suggested could have driven hominin speciation, encephalisation and dispersal out of Africa. One example is the significant hominin speciation and brain expansion event at ∼1.8 Ma that seems to have been coeval with the occurrence of highly variable, extensive, deep-water lakes. This complex, climatically very variable setting inspired first the variability selection hypothesis , which was then the basis for the pulsed climate variability hypothesis . The newer of the two suggests that the long-term drying trend in East Africa was punctuated by episodes of short, alternating periods of extreme humidity and aridity. Both hypotheses, together with other key theories of climate-evolution linkages, are discussed in this paper. Though useful the actual evolution mechanisms, which led to early hominins are still unclear and continue to be debated. However, it is clear that an understanding of East African lakes and their palaeoclimate history is required to understand the context within which humans evolved and eventually left East Africa. [ABSTRACT FROM AUTHOR]

Abstract: The importance of the role played by the tropics in driving and propagating climate change between hemispheres has long been the focus of attention in a bid to evaluate ocean–atmosphere interactions on glacial–interglacial timescales. The Amazon Fan and Ceara Rise in the western equatorial Atlantic Ocean lie directly in the flowpath of the North Brazil Current (NBC) which, as a conduit for the cross-equatorial transport of heat and salinity, is a key component for the heat budget of the North Atlantic. Mg/Ca palaeothermometry and stable oxygen isotope analysis of planktonic foraminifera sampled from 15 sites across the Amazon Fan and Ceara Rise reveal variations in oceanic surface currents and of the dispersal of freshwater from the River Amazon over five timeslices (modern; early Holocene; Younger Dryas; Late Glacial and Marine Isotope Stage 3). Sea surface temperature reconstructions reveal progressive climatic amelioration over the last ~30ka, indicating a temperature increase of ~3.2±1.1°C since the Late Glacial. In conjunction with this warming, values of Δδ18O, a proxy for water column stratification indicates increased vertical mixing of the glacial ocean. The spatial distribution of values of δ18w (the isotopic composition of ambient seawater) is used to infer surface current variations and demonstrates an oceanward shift in the river outflow plume in cold climates representing a prolongation or possibly permanent continuation in the duration of the seasonal retroflection of the NBC causing the curtailment of cross-equatorial transport. A prolongation of this retroflection could have resulted from a mean southward migration of the southern boundary of the ITCZ. [Copyright &y& Elsevier]

Abstract: The development of the Cenozoic East African Rift System (EARS) profoundly re-shaped the landscape and significantly increased the amplitude of short-term environmental response to climate variation. In particular, the development of amplifier lakes in rift basins after three million years ago significantly contributed to the exceptional sensitivity of East Africa to climate change compared to elsewhere on the African continent. Amplifier lakes are characterized by tectonically-formed graben morphologies in combination with an extreme contrast between high precipitation in the elevated parts of the catchment and high evaporation in the lake area. Such amplifier lakes respond rapidly to moderate, precessional-forced climate shifts, and as they do so apply dramatic environmental pressure to the biosphere. Rift basins, when either extremely dry or lake-filled, form important barriers for migration, mixing and competition of different populations of animals and hominins. Amplifier lakes link long-term, high-amplitude tectonic processes and short-term environmental fluctuations. East Africa may have become the place where early humans evolved as a consequence of this strong link between different time scales. [ABSTRACT FROM AUTHOR]

Abstract: The Late Quaternary Amazon deep-sea fan provides a modern analogue to ancient fan systems containing coarse-grained hydrocarbon reservoirs. Sand lenses deposited within the Amazon Fan, due to abrupt shifts in channel pathways called avulsion events, were drilled as part of ODP Leg 155. The hemipelagic sediment directly on top of the avulsion sands was dated using primarily AMS radio carbon dating. This dating shows that these large sand lobes (∼1km3) are triggered by relatively small, millennial scale changes in marine transgression and regression (±5–10m). Relative sea level also controls the architecture of the Channel–levee distributive systems within the Amazon Fan. For example prior to 22k calendar years BP there is a tripartite channel system. After 22ka there is only one active Channel–levee system. Transitions between the multi-channel and single channel configurations are related to variations in the volume of sediment supply resulting in aggradation or erosion of channel floor and levee growth in the canyon-channel transition area. The sensitivity of the Amazon deep-sea Fan sedimentation to relatively small changes in sea level supports one of the central assumptions of the theory of Sequence Stratigraphy. In addition this study demonstrates how traps for hydrocarbons may have been formed in ancient fan systems. [Copyright &y& Elsevier]

Abstract: The general Pleistocene architecture of the Amazon Fan has been reconstructed using sediment recovered by Ocean Drilling Program Leg 155. Huge regional mass-transport deposits (MTDs) make up a significant component of the Amazon Fan. These deposits each cover an area over 15,000km2 (approximately the size of Jamaica), reach a maximum thickness of 200m, and consist of ∼5000Gt of sediment. Benthic foraminiferal fauna analysis and sedimentology indicate that the MTDs originated on the continental slope, which is at least 200km laterally and 1500m above their present position. Each mass-failure event was formed by the catastrophic failure of the continental slope and has been dated and correlated with climate-induced changes in sea level. Studies of the benthic foraminiferal assemblages in the Amazon Fan has been essential to our reconstruction of the origin and cause of these failures. The MTDs contain rare shelf (Quinqueloculina cf. stalkeri, Brizalina aenariensis, Q. lamarckiana, and Pseudononion atlanticum) and dominant upper-middle bathyal species (cassidulinids and buliminids). We conclude that the MTD originated between 200 and 600m water depth, approximately the same zone in which gas hydrates occur. We suggest that the glacial MTDs referred to as Deep Eastern MTD (35–37ka) and Unit R MTD (41–45ka) correlate with rapid drops in sea level which destabilized continental slope gas-hydrate reservoirs causing catastrophic slope failure. An alternative explanation is required for the deglacial MTDs referred to as Western and Eastern Debris Flows (13–14ka) which occurred as sea level rose rapidly during the Bølling-Allerød period. We suggest that the deglaciation of the Andes and the consequent enhanced sediment supply coupled with a shift of the depo-centre to the continental shelf, caused over-burdening and thus slope failure. Evidence for a 2‰ negative shift in both planktonic foraminifera and organic matter coeval with these failures suggest that whatever the cause, there was a large release of methane hydrate associated with each failure. [Copyright &y& Elsevier]

The discovery that methane from dissociation of gas-hydrates could be an important factor in the global carbon cycle resolves the major discrepancy in estimates of the increase of terrestrial biomass from the Last Glacial period to the present. Carbon isotope budgeting using the marine carbon isotopic record results in an estimate centered around 500 GtC, whereas palaeovegetation reconstruction (with biosphere models) gives averages around 1000 GtC. The discrepancy may be resolved by considering release of isotopically light methane through destabilization of gas hydrates. This provides a unique means of estimating the contribution of gas hydrates to the deglacial rise in atmospheric methane. A release of ∼120 GtC methane, makes a biospheric carbon transfer of ∼1000 GtC compatible with the marine carbon isotope data. This, however, represents less than 30% of the enhanced atmospheric methane production between 18 and 8 ka observed in ice cores, supporting the theory that glacial–interglacial variations in atmospheric methane were driven primarily by changes in the extent of tropical and temperate wetlands and not by methane release from clathrates. By balancing the deglacial carbon budget we demonstrate that global carbon models will have to incorporate glacial–interglacial vegetation shifts of at least 1000 GtC, which many currently find difficult. [Copyright &y& Elsevier]

Anthropogenic climate change is affecting people's health, including those with neurological and psychiatric diseases. Currently, making inferences about the effect of climate change on neurological and psychiatric diseases is challenging because of an overall sparsity of data, differing study methods, paucity of detail regarding disease subtypes, little consideration of the effect of individual and population genetics, and widely differing geographical locations with the potential for regional influences. However, evidence suggests that the incidence, prevalence, and severity of many nervous system conditions (eg, stroke, neurological infections, and some mental health disorders) can be affected by climate change. The data show broad and complex adverse effects, especially of temperature extremes to which people are unaccustomed and wide diurnal temperature fluctuations. Protective measures might be possible through local forecasting. Few studies project the future effects of climate change on brain health, hindering policy developments. Robust studies on the threats from changing climate for people who have, or are at risk of developing, disorders of the nervous system are urgently needed. [ABSTRACT FROM AUTHOR]

Abstract Human impacts prior to the Industrial Revolution are not well constrained. We investigate whether the decline in global atmospheric CO 2 concentration by 7–10 ppm in the late 1500s and early 1600s which globally lowered surface air temperatures by 0.15∘C, were generated by natural forcing or were a result of the large-scale depopulation of the Americas after European arrival, subsequent land use change and secondary succession. We quantitatively review the evidence for (i) the pre-Columbian population size, (ii) their per capita land use, (iii) the post-1492 population loss, (iv) the resulting carbon uptake of the abandoned anthropogenic landscapes, and then compare these to potential natural drivers of global carbon declines of 7–10 ppm. From 119 published regional population estimates we calculate a pre-1492 CE population of 60.5 million (interquartile range, IQR 44.8–78.2 million), utilizing 1.04 ha land per capita (IQR 0.98–1.11). European epidemics removed 90% (IQR 87–92%) of the indigenous population over the next century. This resulted in secondary succession of 55.8 Mha (IQR 39.0–78.4 Mha) of abandoned land, sequestering 7.4 Pg C (IQR 4.9–10.8 Pg C), equivalent to a decline in atmospheric CO 2 of 3.5 ppm (IQR 2.3–5.1 ppm CO 2). Accounting for carbon cycle feedbacks plus LUC outside the Americas gives a total 5 ppm CO 2 additional uptake into the land surface in the 1500s compared to the 1400s, 47–67% of the atmospheric CO 2 decline. Furthermore, we show that the global carbon budget of the 1500s cannot be balanced until large-scale vegetation regeneration in the Americas is included. The Great Dying of the Indigenous Peoples of the Americas resulted in a human-driven global impact on the Earth System in the two centuries prior to the Industrial Revolution. Highlights • Combines multiple methods estimating pre-Columbian population numbers. • Estimates European arrival in 1492 lead to 56 million deaths by 1600. • Large population reduction led to reforestation of 55.8 Mha and 7.4 Pg C uptake. • 1610 atmospheric CO2 drop partly caused by indigenous depopulation of the Americas. • Humans contributed to Earth System changes before the Industrial Revolution. [ABSTRACT FROM AUTHOR]

Abstract: Variations in the strength of coastal upwelling in the South East Atlantic Ocean and summer monsoonal rains over South Africa are controlled by the regional atmospheric circulation regime. Although information about these parameters exists for the last glacial period, little detailed information exists for older time periods. New information from ODP Site 1085 for Marine Isotope Stages (MIS) 12–10 shows that glacial–interglacial productivity trends linked to upwelling variability followed a pattern similar to the last glacial cycle, with maximums shortly before glacial maxima, and minimums shortly before glacial terminations. During the MIS-11/10 transition, several periodic oscillations in productivity and monsoonal proxies are best explained by southwards shifts in the southern sub-tropical high-pressure cells followed by abrupt northwards shifts. Comparison to coeval sea-surface temperature measurements suggests that these monsoonal cycles were tightly coupled to anti-phased hemispheric climate change, with an intensified summer monsoon during periods of Northern (Southern) Hemisphere cooling (warming). The timing of these events suggests a pacing by insolation over precession periods. A lack of similar regional circulation shifts during the MIS-13/12 transition is likely due to the large equatorwards shift in the tropical convection zone that occurred during this extreme glaciation. [ABSTRACT FROM AUTHOR]

Abstract: An extensive study of Late Pleistocene continental slope submarine mass movements was undertaken. Twenty-six well-dated mass movements occurred during the last 45kaBP in the North Atlantic sector. A latitudinal trend is observed: between 45 and 12kaBP most events occur in the mid- to low-latitudes, post-12kaBP high-latitude occurring events dominate. A cluster of events is associated with the Last Glacial sea level lowstand and Termination 1B. Further events are associated with Termination 1A and the Holocene. Prior to 23kaBP no clear relationship with the ice core atmospheric methane record is observed, in contrast during and following the deglaciation there is a possible relationship with atmospheric methane. High-latitude mass movements are primarily controlled by cyrospheric-induced variations in sedimentation and local sea level. In high latitudes, the glaciation subdues mass movement activity through reduced seisimicity, sediment supply and ocean temperatures. Deglaciation increases the sediment supply, seisimicity and ocean temperatures, thus increasing the likelihood of continental slope failures. For example the Storegga event coincides with high isostatic uplift and postglacial seisimicity, while the Andøya and Trænadjupet events occur before and after the peak rates respectively. In contrast low latitudes experience greater risk of slope failures during glacial periods from falling sea levels, although during the deglacial and interglacial period there is a potential for failure from changes in deposition centres and rates, as well as warming ocean temperatures potentially leading to dissociation of gas hydrates. The ongoing rapid deglaciation of coastal Greenland and Antarctica and consequent rapid input of sediment, isostatic uplift, crustal stress release and warming bottom water temperature at the shelf break will increase the risk of continental slope failure in these regions. [Copyright &y& Elsevier]

The southeast Atlantic Ocean is dominated by two major oceanic systems: the Benguela Upwelling System, one of the world's most productive coastal upwelling cells and the Agulhas Leakage, which is important for transferring warm salty water from the Indian Ocean to the Atlantic Ocean. Here, we present a multi-proxy record of marine sediments from ODP Site 1087. We reconstruct sea surface temperatures ( U 37 K ′ and TEX 86 indices), marine primary productivity (total chlorin and alkenone mass accumulation rates), and terrestrial inputs derived from southern Africa (Ti/Al and Ca/Ti via XRF scanning) to understand the evolution of the Southeast Atlantic Ocean since the late Pliocene. In the late Pliocene and early Pleistocene, ODP Site 1087 was situated within the Benguela Upwelling System, which was displaced southwards relative to present. We recognize a series of events in the proxy records at 3.3, 3.0, 2.2, 1.5, 0.9 and 0.6 Ma, which are interpreted to reflect a combination of changes in the location of major global wind and oceanic systems and local variations in the strength and/or position of the winds, which influence nutrient availability. Although there is a temporary SST cooling observed around the initiation of Northern Hemisphere glaciation (iNHG), proxy records from ODP Site 1087 show no clear climatic transition around 2.7 Ma but instead most of the changes occur before this time. This observation is significant because it has been previously suggested that there should be a change in the location and/or strength of upwelling associated with this climate transition. Rather, the main shifts at ODP Site 1087 occur at ca. 0.9 Ma and 0.6 Ma, associated with the early mid-Pleistocene transition (EMPT), with a clear loss of the previous upwelling-dominated regime. This observation raises the possibility that reorganisation of southeast Atlantic Ocean circulation towards modern conditions was tightly linked to the EMPT, but not to earlier climate transitions. [ABSTRACT FROM AUTHOR]

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. [ABSTRACT FROM AUTHOR]

The Pliocene–Pleistocene Transition (PPT), from around 3.2 to 2.5 million years ago (Ma), represented a major shift in the climate system and was characterized by a gradual cooling trend and the appearance of large continental ice sheets over northern Eurasia and North America. Paleo evidence indicates that the PPT was accompanied and possibly caused by a decrease in atmospheric CO 2 , but the temporal resolution of CO 2 reconstructions is low for this period of time and uncertainties remain large. Therefore, instead of applying existent CO 2 reconstructions we solved an ‘inverse’ problem by finding a schematic CO 2 concentration scenario that allows us to simulate the temporal evolution of key climate characteristics in agreement with paleoclimate records. To this end, we performed an ensemble of transient simulations with an Earth system model of intermediate complexity from which we derived a best guess transient CO 2 scenario for the interval from 3.2 to 2.4 Ma that gives the best fit between the simulated and reconstructed benthic δ 18 O and global sea surface temperature evolution. Our data-constrained CO 2 scenarios are consistent with recent CO 2 reconstructions and suggest a gradual CO 2 decline from 375–425 to 275–300 ppm, between 3.2 and 2.4 Ma. In addition to a gradual decline, the best fit to paleoclimate data requires the existence of pronounced CO 2 variability coherent with the 41-kyr (1 kyr = 1000 years) obliquity cycle. In our simulations the long-term CO 2 decline is accompanied by a relatively abrupt intensification of Northern Hemisphere glaciation at around 2.7 Ma. This is the result of a threshold behaviour of the ice sheets response to gradual CO 2 decrease and orbital forcing. The simulated Northern Hemisphere ice sheets during the early Pleistocene glacial cycles reach a maximum volume equivalent to a sea level drop of about 40 m. Both ice volume and benthic δ 18 O are dominated by 41-kyr cyclicity. Our simulations suggest that before 2.7 Ma Greenland was ice free during summer insolation maxima and only partly ice covered during periods of minimum summer insolation. A fully glaciated Greenland comparable to its present-day ice volume is modelled only during glacial maxima after 2.7 Ma and more continuously after 2.5 Ma. [ABSTRACT FROM AUTHOR]

The hypothesis of a connection between the onset (or intensification) of Northern Hemisphere Glaciation, the stepwise increase in African aridity (and climate variability), and an important mammalian (including hominin) species turnover is a textbook example of the initiation of a scientific idea and its propagation in science. It is, however, also an example of the persistent popularity of a hypothesis despite mounting evidence against it. A critical review of key publications on the topic and statistical re-analysis of key records of global ice volume and African climate leads to three conclusions: (1) The Northern Hemisphere Glaciation was a gradual process occurring between ∼3.5 and 2.5 Ma, not a single event at ∼2.8 Ma or at any other time. (2) A consistent stepwise (+/−0.2 Ma) transition toward greater aridity in Africa at ∼2.8 Ma does not exist; instead, there are regionally different, gradual transitions partly in connection with the intensification of the Northern Hemisphere Glaciation, but above all with the establishment of the tropical Walker Circulation after ∼2 Ma. (3) Mammalian (including hominin) species turnovers at this time also appear to have been gradual, rather than stepwise. • We falsified the hypothesis of a connection between Northern Hemisphere Glaciation, African climate and human evolution. [ABSTRACT FROM AUTHOR]

The Chew Bahir Drilling Project (CBDP) aims to test possible linkages between climate and hominin evolution in Africa through the analysis of sediment cores that have recorded environmental changes in the Chew Bahir basin (CHB). In this statistical project we used recurrence plots (RPs) together with a recurrence quantification analysis (RQA) to distinguish two types of variability and transitions in the Chew Bahir aridity record and compare them with the ODP Site 967 wetness index from the eastern Mediterranean. The first type of variability is one of slow variations with cycles of ∼20 kyr, reminiscent of the Earth's precession cycle, and subharmonics of this orbital cycle. In addition to these cyclical wet-dry fluctuations in the area, extreme events often occur, i.e. short wet or dry episodes, lasting for several centuries or even millennia, and rapid transitions between these wet and dry episodes. The second type of variability is characterized by relatively low variation on orbital time scales, but significant century-millennium-scale variations with progressively increasing frequencies. Within this type of variability there are extremely fast transitions between dry and wet within a few decades or years, in contrast to those within Type 1 with transitions over several hundreds of years. Type 1 variability probably reflects the influence of precessional forcing in the lower latitudes at times with maximum values of the long (400 kyr) eccentricity cycle of the Earth's orbit around the sun, with the tendency towards extreme events. Type 2 variability seems to be linked with minimum values of this cycle. There does not seem to be a systematic correlation between Type 1 or Type 2 variability with atmospheric CO 2 concentration. The different types of variability and the transitions between those types had important effects on the availability of water, and could have transformed eastern Africa's environment considerably, which would have had important implications for the shaping of the habitat of H. sapiens and the direct ancestors of this species. [ABSTRACT FROM AUTHOR]