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A new global synthesis and biomization of long (> 40 kyr) pollen-data records is presented and used with simulations from the HadCM3 and FAMOUS climate models and the BIOME4 vegetation model to analyse the dynamics of the global terrestrial biosphere and carbon storage over the last glacial–interglacial cycle. Simulated biome distributions using BIOME4 driven by HadCM3 and FAMOUS at the global scale over time generally agree well with those inferred from pollen data. Global average areas of grassland and dry shrubland, desert, and tundra biomes show large-scale increases during the Last Glacial Maximum, between ca. 64 and 74 ka BP and cool substages of Marine Isotope Stage 5, at the expense of the tropical forest, warm-temperate forest, and temperate forest biomes. These changes are reflected in BIOME4 simulations of global net primary productivity, showing good agreement between the two models. Such changes are likely to affect terrestrial carbon storage, which in turn influences the stable carbon isotopic composition of seawater as terrestrial carbon is depleted in 13C.

Giant vertebrates dominated many Pleistocene ecosystems. Many were herbivores, and their sudden extinction in prehistory could have had large ecological impacts. We used a high-resolution 130,000-year environmental record to help resolve the cause and reconstruct the ecological consequences of extinction of Australia's megafauna. Our results suggest that human arrival rather than climate caused megafaunal extinction, which then triggered replacement of mixed rainforest by sclerophyll vegetation through a combination of direct effects on vegetation of relaxed herbivore pressure and increased fire in the landscape. This ecosystem shift was as large as any effect of climate change over the last glacial cycle, and indicates the magnitude of changes that may have followed megafaunal extinction elsewhere in the world.

Today, southeastern Australia experiences a winter-dominated rainfall regime, governed by the seasonal migration of the highly zonal Southern Hemisphere subtropical anticyclone. The late Cenozoic history of this rainfall regime is poorly understood, but it has been widely accepted that its onset was a product of the intensification and northward migration of the subtropical anticyclone, driven by steepening of hemispheric temperature gradients associated with the initiation of extensive Northern Hemisphere glaciation, ∼2.6 million years ago (Ma). Here, we use fossil beetle remains from Stony Creek Basin, a small palaeolake record in upland southeastern Australia deposited over ∼280,000 years between ∼1.84 and 1.56 Ma, to quantitatively reconstruct regional climate during the Early Pleistocene. Climate reconstructions based on coexistence of extant beetle taxa indicate that temperatures were consistently 1-3 °C warmer than present, and rainfall as high as or substantially higher than today, throughout the record. In particular, beetle data indicate that rainfall was similar to today during winter, but 2-2.4 times higher than today during summer. This is consistent with the presence of diverse rainforest pollen also present in the record, and indicates that the modern, winter-dominated rainfall regime was not yet in place by ∼1.5 Ma, at least one million years later than previously thought. We suggest that the Southern Hemisphere anticyclonic circulation must have been much less intense during the Early Pleistocene than today, rather than shifted meridionally as previously argued.

Terrestrial climate responses to orbital forcing during the late Pliocene-early Pleistocene are poorly understood, particularly in the Southern Hemisphere, but are important for determination of the timing of regional climate evolution early in the history of the glaciated Quaternary world. We present a pollen record from southeastern Australia that shows marked cyclic change over some 280,000 yr straddling the Pliocene-Pleistocene boundary. Rainforest communities responded to climate forcing primarily within the precession and eccentricity bands, suggesting that major vegetation changes were driven directly by summer insolation, rather than by obliquity-dominated glacial cycles.

The degree to which Southern Hemisphere climatic changes during the end of the last glacial period and early Holocene (30-8 ka) were influenced or initiated by events occurring in the high latitudes of the Northern Hemisphere is a complex issue. There is

The degree to which palaeoclimatic changes in the Southern Hemisphere co-varied with events in the high latitude Northern Hemisphere during the Last Termination is a contentious issue, with conflicting evidence for the degree of 'teleconnection' between different regions of the Southern Hemisphere. The available hypotheses are difficult to test robustly, however, because there are few detailed palaeoclimatic records in the Southern Hemisphere. Here we present climatic reconstructions from the southwestern Pacific, a key region in the Southern Hemisphere because of the potentially important role it plays in global climate change. The reconstructions for the period 20-10 kyr BP were obtained from five sites along a transect from southern New Zealand, through Australia to Indonesia, supported by 125 calibrated 14C ages. Two periods of significant climatic change can be identified across the region at around 17 and 14.2 cal kyr BP, most probably associated with the onset of warming in the West Pacific Warm Pool and the collapse of Antarctic ice during Meltwater Pulse-1A, respectively. The severe geochronological constraints that inherently afflict age models based on radiocarbon dating and the lack of quantified climatic parameters make more detailed interpretations problematic, however. There is an urgent need to address the geochronological limitations, and to develop more precise and quantified estimates of the pronounced climate variations that clearly affected this region during the Last Termination.

There are many geochemical reconstructions of environmental change in the mid and high latitudes but relatively few in the tropical latitudes, despite their considerable potential for reconstructing environmental processes that cannot be identified using

The El Niño/Southern Oscillation (ENSO) phenomenon is believed to have operated continuously over the last glacial-interglacial cycle. ENSO variability has been suggested to be linked to millennial-scale oscillations in North Atlantic climate during that

Aim: This paper documents reconstructions of the vegetation patterns in Australia, Southeast Asia and the Pacific (SEAPAC region) in the mid- Holocene and at the last glacial maximum (LGM). Methods: Vegetation patterns were reconstructed from pollen data

Over 1000 marine and terrestrial pollen diagrams and some hundreds of vertebrate faunal sequences have been studied in the Austral-Asian region bisected by the PEPII transect, from the Russian arctic extending south through east Asia, Indochina, southern

Lynch's Crater in northeastern Australia provides a long, continuous record of environmental change within the Late Quaternary. Here, we present newly determined radiocarbon ages, using acid-base-acid stepped combustion (ABA-SC) and acid-base-wet oxidation stepped combustion (ABOX-SC) pretreatment strategies. The new results largely confirm the original untreated radiocarbon results for the uppermost 9 m of sediments, (ca. 35 ka BP). Below this depth, results from both pretreatment methods are in stratigraphic agreement and extend the dating of the record from 38 ka BP to about 48 ka BP, although an apparent increased sedimentation rate below 12 m is questionable. The scarcity of "charcoal" in several of the samples raises questions regarding the application of ABOX-SC to lake or swamp sediments, with evidence for contributions from younger, chemically resistant bacterial carbon along with fine "charcoal" in some samples. However, the extent to which this phenomenon is significant to the final age estimate appears to be sample specific, and is probably dependent upon the length of the wet oxidation step in the pretreatment.

Lynch's Crater preserves a continuous, high-resolution record of environmental changes in north Queensland. This record suggests a marked increase in burning that appears to be independent of any known major climatic boundaries. This increase is accompanied, or closely followed, by the virtually complete replacement of rainforest by sclerophyll vegetation. The absence of any major climatic shift associated with this increase in fire frequency therefore has been interpreted as a result of early human impact in the area. The age for this increase in burning, on the basis of conventional radiocarbon dating, was previously thought to be approximately 38 000 14C yr BP, supporting the traditional model for human arrival in Australia at 40 000 14C yr BP Here we have applied a more rigorous pre-treatment and graphitisation procedure for radiocarbon dating samples from the Lynch's Crater sequence. These new dates suggest that the increase in fire frequency occurred at 45 000 14C yr BP, supporting the alternative view that human occupation of Australia occurred by at least 45 000-55 000 cal. yr BP.