New dating confirms that people occupied the Australian continent before the earliest time inferred from conventional radiocarbon analysis. Many of the new ages were obtained by accelerator mass spectrometry 14C dating after an acid–base–acid pretreatment with bulk combustion (ABA-BC) or after a newly developed acid–base–wet oxidation pretreatment with stepped combustion (ABOX-SC). The samples (charcoal) came from the earliest occupation levels of the Devil's Lair site in southwestern Western Australia. Initial occupation of this site was previously dated 35,000 14C yr B.P. Whereas the ABA-BC ages are indistinguishable from background beyond 42,000 14C yr B.P., the ABOX-SC ages are in stratigraphic order to ∼55,000 14C yr B.P. The ABOX-SC chronology suggests that people were in the area by 48,000 cal yr B.P. Optically stimulated luminescence (OSL), electron spin resonance (ESR) ages, U-series dating of flowstones, and 14C dating of emu eggshell carbonate are in agreement with the ABOX-SC 14C chronology. These results, based on four independent techniques, reinforce arguments for early colonization of the Australian continent.

Chemical analyses of the clay-sized fractions of 564 continuous sediment samples (200-yr resolution) from composite core OL90/92 allow quantification of an abundance of glacial rock flour. Rock flour produced during glacier advances is represented by clay-sized plagioclase, K-feldspar, and biotite in homogeneous internal composition. The abundance of rock flour is deemed proportional to the intensity of glacies advances. Age control for the composite section is provided by combining previously published radiocarbon dates on organics, U/Th dates on ostracode shells, and U/Th dates on saline minerals from nearby Searles Lake correlated to OL92 by pollen. The rock flour record displays three levels of variability: (1) a dominant one of about 20,000 yr related to summer insolation and precipitation; (2) an intermediate one of 3000–5000 yr, perhaps related to North Atlantic Heinrich events; and (3) a minor one of 1000–2000 yr, perhaps related to North Atlantic thermohaline-driven air-temperature variation.

Orbital forcing is known to play a primary role in regulating the strength of the south Asian monsoon circulation. In this study, a comparison is made between orbital forcing and Pacific sea surface temperature (SST) forcing of the monsoon through a sequence of atmospheric general circulation model experiments configured for 6,000 and 9,000 yr B.P. Early–mid Holocene orbital parameters are shown to increase continental seasonality as well as the meridional mean, the zonal mean, and the summer monsoon circulations. Winds in the southeast Asian monsoon are weakened by warm Pacific SST to such an extent that the increase in strength caused by early Holocene orbital parameters is offset. These results imply that SSTs are potentially as important as orbital parameters in governing the monsoon and that more data—particularly from the equatorial Pacific—are crucial to deciphering Holocene climate.

Paleoprecipitation reconstructions on the basis of pollen are well known, but they do not provide high temporal resolution for glacial periods. High-resolution paleoprecipitation reconstructions for the last glaciation based on the isotopic record organic matter in loess from Nussloch (Rhine Valley, Germany) are consistent with paleoprecipitation inferred from peat in the same area using an independant method. Thus, δ13C of loess organic matter can be used as a proxy for paleoprecipitation.

Carbon isotopes of soil organic matter (SOM) were used to evaluate and establish the chronology of the vegetation dynamics of an ecosystem presently composed of savannas surrounded by forests. The study was carried out on a 200-km transect along highway BR 319, on the border of Amazonas and Rondônia states, in southern Amazon, Brazil. Large ranges in δ13C values were observed in SOM collected from profiles in the savanna (−27 to −14‰) and forest regions (−26 to −19‰), reflecting changing distribution of 13C-depleted C3 forest and 13C-enriched C4 savanna vegetation in response to climate change. These results indicate that from about 17,000 to 9000 14C yr B.P., the study area was covered by forest vegetation. Between approximately 9000 and 3000 14C yr B.P., savanna vegetation expanded at the expense of the forest. Although the expansion of savanna did not occur with the same intensity along the study transect, this process was very clearly registered by 13C-enrichment in the SOM. Since 3000 14C yr B.P., the carbon isotope data suggest that forested regions have expanded. This study adds to the mounting evidence that extensive forested areas existed in the Amazon during the last glaciation and that savanna vegetation expanded in response to warm and dry conditions during the early to middle Holocene.

New pollen data from a core at Lagoa do Caçó, Maranhão state, Brazil (2°58′S 43°25′W; 120 m elevation), show higher frequencies of Podocarpus at the end of the Pleistocene than today. The increase in Podocarpus, which follows the successive increase of various pioneer species such as Didymopanax, Melastomataceae/Combretaceae, and Cecropia, implies a progressive late-glacial increase of moist and cool climatic conditions. A comparable increase in Podocarpus is found in other lowland records in Amazonia. A review of published pollen data from Amazonia suggests that the moisture source was from the southeast. By contrast, present-day moisture comes from the tropical Atlantic and from the Amazon basin, with its convective precipitation. The likely cause for the southeastern moisture source between ca. 15,000 and 14,500 cal yr B.P. was enhanced polar (Antarctic) advection that reached low latitudes and maintained year-round the meteorological equator in its austral-winter position at northern latitudes or reduced drastically its southward summer displacement. This hypothesis is consistent with marine and ice core records.

Pollen and algae from Owens Lake in eastern California provide evidence for a series of climatic oscillations late in the last glaciation. Juniper woodland, which dominated the Owens Valley from 16,200 to 15,500 cal yr B.P., suggests much wetter conditions than today. Although still wetter and cooler than today, the area then became fairly warm and dry, with woodland being replaced by shrubs (mainly sagebrush) from 15,500 to 13,100 cal yr B.P. Next, Chenopodiaceae (shadscale) increased, woody species declined, and lake levels fell—all evidence for a brief (ca. 100–200 yr) drought about 13,000 cal yr B.P. The climate continued to oscillate between wet and dry from 13,000 to 11,000 cal yr B.P. After 11,000 cal yr B.P., low lake levels and the increased dominance of desert shrubs indicate the beginning of warm, dry Holocene conditions. The region's climate was unstable during the Younger Dryas but uncertainities in dating prevent identification of the Younger Dryas interval in the Owens Lake record. Comparison of the Owens Lake record with studies in the Sierra Nevada and Great Basin suggest that the climate was generally wetter between 13,000 and 11,000 cal yr B.P., with warmer summers, although no consistent pattern of climate change emerges.

Analysis of diatoms, pollen, and the carbon-isotopic composition of a sediment core from a brackish marsh in the northern part of the San Francisco Estuary has provided a paleosalinity record that covers the past 3000 yr. Changes in marsh composition and diatom frequencies are assumed to represent variations in freshwater inflow to the estuary. Three periods of relatively high salinity (low freshwater inflow) are indicated, 3000 to 2500 cal yr B.P., 1700 to 730 cal yr B.P., and ca. A.D. 1930 to the present. The most recent period of high salinity is primarily due to upstream storage and water diversion within the Sacramento–San Joaquin watershed, although drought may also have been a factor. The two earlier high-salinity periods are likely the result of reduced precipitation. Low salinity (high freshwater flow) is indicated for the period 750 cal yr B.P. to A.D. 1930.

Studies of some 70 bore holes around ancient Pompeii, on the southwestern slope of the Somma-Vesuvius volcano, allow the reconstruction of Holocene environments earlier than the A.D. 79 eruption. This eruption produced about 10 km3 of pyroclastic material that buried the Roman cities of Pompeii, Herculaneum, and Stabiae and promoted a shoreline progradation of 1 km. The Sarno coastal plain, in a post-Miocene sedimentary basin, has been affected by Somma-Vesuvius volcanic activity since the late Pleistocene. At the Holocene transgressive maximum, the sea reached an area east of ancient Pompeii and formed a beach ridge (Messigno, 5600 and 4500 14C yr B.P.) more than 2 km inland from the present shore. Progradation of the plain due to high volcanic supply during the following highstand resulted in a new beach ridge (Bottaro-Pioppaino, 3600 14C yr B.P.) 0.5 km seaward of the Messigno ridge. Ancient Pompeii was built as the shoreline continued to prograde toward its present position. Deposits of the A.D. 79 eruption blanketed the natural levees of the Sarno River, marshes near the city and on the Sarno's floodplain, the morphological highs of Messigno and Bottaro-Pioppaino beach ridges, and the seashore. That shore was probably 1 km landward of the present one.

Knowledge of sea-level change in the southern Baltic Sea region is important for understanding the variations in late Pleistocene and Holocene sea-level change across northern Europe. These variations are a consequence of the response of the Earth's crust to the deglaciation of Fennoscandia and of the water added to the oceans from the melting of all Pleistocene ice sheets. The sedimentological and geochemical composition of five sediment cores from the lagoonal Oder Estuary offers new observational evidence for sea-level change and coastal development in the southern Baltic Sea region. The combined use of several geochemical proxies (organic carbon, nitrogen, calcium carbonate and biogenic opal contents, Corg/S and Corg/N ratios, δ13C values of organic matter, and δ15N values) is a new approach for the study area. The chemical evidence of this multiproxy approach allows clear identification of several stages in the development of the lagoonal environment: postglacial lake stages with sandy sedimentation during the Older Dryas and the Allerød stades, lacustrine phases with high autochthonous productivity during the Atlantic stade, terrestrial stages with peat formation at the beginning of the Subboreal stade, sedimentation as a result of marine transgression, and brackish sedimentation after the formation of sand spits and barrier islands during the Subatlantic stade. The stages are the result of regional sea-level change owing to complex shoreline development. They support the tentative sea-level curve proposed nearly 20 years ago for the region. In addition, changes in Oder River input in response to climate conditions is monitored. Whereas high terrigenous input of organic matter from the Oder River occurred during periods of humid climate during the Allerød, Atlantic, and Subatlantic stades, Oder River discharge decreased with drier and cooler climate conditions during the Subboreal stade. Furthermore, the geochemical evidence points to local anomalies such as the significance of river input and additional sulfate supply into the Oder lagoon for the composition of the sediments. Overall, the results provide a framework for future studies, which would allow for a more detailed comparison with other, similar environments.

Microscopic charcoal preserved in lake and swamp sediments from 10 sites in Indonesia and Papua New Guinea and from 5 sites in Central and South America have been used to reconstruct long-term fire histories for these two regions. Comparison of these records demonstrates that fire is promoted during periods of rapid climate change and high climate variability, regardless of the presence or absence of humans. Broad synchrony of changes in corrected charcoal values in each region supports an atmospheric transmission of the climate signal via the dominant large-scale atmospheric circulation systems (Walker Circulation) that appears to have persisted since 16,000 cal yr B.P. Altered climate boundary conditions under the influence of changing El Niño-related variability, insolation, sea level, and sea surface temperature all influenced the strength of this connection. Correlation of biomass burning records between the regions tends to increase in the Holocene. The main period of inverse correlation occurs during the Younger Dryas Stade, when extratropical climate most affected the tropics. The strongest correlation between the two regions postdates 5000 cal yr B.P., when El Niño-related variability intensified. Fluctuations in tropical biomass burning are at least partly controlled by orbital forcing (precession), although extratropical climate influences and human activity are also important.