K.V. Kremenetski

University of California, Los Angeles | UCLA · Department of Geography

Continental-scale estimates of vegetation cover, including land-surface properties and biogeographic trends, reflect the response of plant species to climate change over the past millennia. These estimates can help assess the effectiveness of simulations of climate change using forward and inverse modelling approaches. With the advent of transient...

California has experienced a dry 21(st) century capped by severe drought from 2012 through 2015 prompting questions about hydroclimatic sensitivity to anthropogenic climate change and implications for the future. We address these questions using a Holocene lake sediment record of hydrologic change from the Sierra Nevada Mountains coupled with marin...

Extinction of the woolly mammoth in Beringia has long been subject to research and speculation. Here we use a new geo-referenced database of radiocarbon-dated evidence to show that mammoths were abundant in the open-habitat of Marine Isotope Stage 3 (∼45-30 ka). During the Last Glacial Maximum (∼25-20 ka), northern populations declined while those...

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Russia's West Siberian Lowland (WSL) contains the most extensive peatlands on Earth with many underlain by permafrost. We present a new database of 12 705 measurements of vertical water content and bulk soil properties from 98 permafrost and non-permafrost cores collected in raised bogs and peat plateaus across the region, together with in-situ mea...

The paper presents results of morphoscopic studies of quartz grains recovered from sands underlying surficial peat over the West Siberian Plain. The field materials were collected in the course of the Russian–American expedition in 1999–2001. The data obtained proved the existence of a vast area in West Siberia similar to cold deserts in appearance...

Pollen analyses and radiocarbon dates from Zhukovskoye peat mire (56°20′N, 84°50′E), situated in the south-eastern part of the boreal forest (taiga) zone of West Siberia, suggest that climatic oscillations of the Lateglacial were well expressed in the region. These events are tentatively correlated with the Alleröd warming and the Younger Dryas coo...

We present a database of late-Quaternary plant macrofossil records for northern Eurasia (from 23° to 180°E and 46° to 76°N) comprising 281 localities, over 2300 samples and over 13,000 individual records. Samples are individually radiocarbon dated or are assigned ages via age models fitted to sequences of calibrated radiocarbon dates within a secti...

We present a database of late-Quaternary plant macrofossil records for northern Eurasia (from 23 to 180 E and 46 to 76 N) comprising 281 localities, over 2300 samples and over 13,000 individual records. Samples are individually radiocarbon dated or are assigned ages via age models fitted to sequences of calibrated radiocarbon dates within a section...

In terrestrial records from Central and Eastern Europe the end of the Last Interglacial seems to be characterized by evident climatic and environmental instabilities recorded by geochemical and vegetation indicators. The transition (MIS 5e/5d) from the Last Interglacial (Eemian, Mikulino) to the Early Last Glacial (Early Weichselian, Early Valdai)...

The 7m thick sediment profile at Plinz in northern Thuringia (central Germany) covering the time span between 10,000 and at least 8000 14C years BP (about 11,600–9000calBP) was studied using radiocarbon, stable isotopes and pollen analysis. The results reflect the very fast climatic transition from the Late Glacial to the Holocene as a change from...

Southern California relies heavily upon imported water from the Sacramento and Colorado river systems to augment local supplies and to mitigate the impacts of drought. In this paper a ‘perfect drought’ is defined as a prolonged drought that affects southern California, the Sacramento River basin and the upper Colorado River basin simultaneously. Ex...

The Russian treeline is a dynamic ecotone typified by steep gradients in summer temperature and regionally variable gradients in albedo and heat flux. The location of the treeline is largely controlled by summer temperatures and growing season length. Temperatures have responded strongly to twentieth-century global warming and will display a magnif...

Geochemical and palynological studies of lacustrine sediments from the standard Eemian-Early Weichselian profiles Gröbern, Neumark-Nord and Klinge (Germany, Central Europe) document at least two warming events during the transition from the Eemian to the Early Weichselian. The first pronounced warming phase takes place towards the very end of the E...

Mapped correlations between annual discharges (AD 1938–1990) of the major Eurasian rivers entering the Arctic Ocean (Severnaya Dvina, Pechora, Ob', Yenisey, Lena, and Kolyma) demonstrate a positive relationship between discharge and the Palmer Drought Severity Index (PDSI) within the individual basins and more distant areas. The relationship betwee...

Kazakhstan is located in central Asia between Caspian Sea and Tiang-Shang Mountains. Few well dated holocene sequences from the forest-steppe and steppe belt of Kazakhstan provided information about the vegetation and climate history. Mokhovoe mire was studied in the watershed of Tobol and Ubagan rivers. That's the most thick peat mire in northern...

Ples is the key-section that represents the Mikulino (Eemian) interglaciation and early part of the Valdai (Weichselian) glacial epoch in the north-central Russia. Pollen profile of this section reflects spread of the broad-leaved forest dominated by Quercus, Ulmus, and Tilia with participation of Acer, Fraxinus and Carpinus in the optimum phase of...

An analysis of 1516 radiocarbon dates demonstrates that the development of the current circumarctic peatlands began ∼16.5 thousand years ago (ka) and expanded explosively between 12 and 8 ka in concert with high summer insolation and increasing temperatures. Their rapid development contributed to the sustained peak in CH4 and modest decline of CO2...

Through the support of the Paleoenvironmental Arctic Sciences (PARCS) program sponsored by the National Science Foundation two working groups of over 50 scientists have been synthesizing data from more than 160 terrestrial, ice-core and marine records from the Arctic. The aim of the synthesis is to provide a unified picture of the magnitude of the...

Paleogeographic reconstructions, particularly those of climatic trends, can most reliably be substantiated by data on paleovegetation, the ecological evolution of which is clearly reflected in variations in the proportions of taxons that constitute spore-pollen spectra. New palynological data obtained enabled us to reconstruct vegetation and climat...

A sediment core from Lake KP3 (unofficial name) located near the coastline on the northern Kola Peninsula, 100km east-south-east from Murmansk, Russia (69°04′19″N, 36°00′40″E) provides palynological evidence for the vegetation and climate history of the last 14,000 years. During the Younger Dryas time the climate was cold and vegetation cover aroun...

The peatlands of the West Siberia Lowland (WSL) are of global significance owing to the massive carbon (C) stocks they hold (70 Pg C) and their location at the focus of both observed and predicted Arctic warming. Greater understanding of the potential warm-climate sensitivity of northern peatlands using paleoecological approaches is limited by past...

Tropical wetlands are thought to have been a major driver of early Holocene fluctuations in atmospheric methane, in part because high-latitude peatlands were not extensively developed in North America by ~11 ka, a period of peak methane concentration. However, the timing of peatland expansion in Russia, which contains nearly half of the world's pea...

The development of extensive peatlands in the circumpolar subarctic and arctic zones produced immense alterations in edaphic conditions, hydrology, vegetation, animal forage and habitat conditions, human land-use potential, carbon storage and land-atmosphere fluxes of CO2 and CH4. There has been much speculation regarding the impact that circumpola...

1] The West Siberian Lowland (WSL) contains the world's most extensive peatlands and a substantial fraction of the global terrestrial carbon pool. Despite its recognition as a carbon reservoir of great significance, the extent, thickness, and carbon content of WSL peatlands have not been analyzed in detail. This paper compiles a wide array of data...

The broad and flat valley of the upper Dnister in western Ukraine is characterized by a complex setting of ecotopes and a relatively natural state of floodplain dynamics. Excellent geo-archives–extended peat bogs and postglacial river terraces–document late Quaternary landscape evolution with special regard to changes in fluvial morphodynamics, veg...

Interpolar methane gradient (IPG) data from ice cores suggest the “switching on” of a major Northern Hemisphere methane source in the early Holocene. Extensive data from Russia's West Siberian Lowland show (i) explosive, widespread peatland establishment between 11.5 and 9 thousand years ago, predating comparable development in North America and sy...

The Western Siberian lowlands (WSL) are the world's largest high-latitude wetland, and possess over 900,000 km2 of peatlands. The peatlands of the WSL are of major importance to high-latitude hydrology, carbon storage and environmental history. Analysis of the existing Russian data suggests that the mean depth of peat accumulation in the WSL is 256...

The main climatic oscillations of the Lateglacial/Early Holocene (Allerød, Younger Dryas, and Preboreal) can be distinguished all over Eastern Europe and Siberia. Distribution of the main climatic indices in the Lateglacial/Early Holocene, from west to east in Northern Eurasia, shows that variations of the mean January temperature (tJano) were larg...

The West Siberian Lowland (WSL) is the world's largest high-latitude wetland, with a 1.8 X 106 km2 forest-palustrine zone covering nearly 2/3 of western Siberia. Over half of this area consists of peatlands, which since the early Holocene have sequestered atmospheric carbon in the form of undecomposed plant matter. The total carbon pool of the WSL...

The extent to which northern peatlands respond to or influence climate change is an unresolved question in Arctic science. Recent studies in Alaska, Canada, and Fennoscandia have raised concerns that northern peatlands, while currently a net sink or minor source of atmospheric CO 2 , may become a significant CO 2 source under a warming climate. Exp...

The Late Glacial and Holocene history of the plant cover in the Moscow Region was reconstructed based on spore-and-pollen data from the bottom deposits of the Myshetskoe-Dolgoe Lake (the Klin-Dmitrov Ridge). In the Late Glacial Period, open landscapes and a mosaic plant cover prevailed. Pine-birch forests grew around the lake 10000-8000 years BP. B...

An integrated analysis was implemented of the multilayered Acheulian cave site Sel-Ungur in Kirghistan. Cave deposits are represented by tuffes, silts loams with rock debris. Sedimentation strata were formed in one climatic cycle. The pollen of coniferous and large-leaved species that are now not found in Soviet Central Asia was identified. Bone fo...

The West Siberian Plain (WSP) of arctic Russia stores a major fraction of the global soil carbon pool in the form of peat, with annual accumulation rates thought to be on the order of 1012 g C. Determining locations of present carbon accumulation in this region is essential for understanding future possible carbon cycle dynamics and globally signif...

The West Siberian Lowland (WSL) stores a major fraction of the global soil carbon pool in peatlands that occupy over 400,000 km2 in the region. Nearly half of the world's peatlands may exist in the WSL alone and are thought to accumulate carbon on the order of 1012 g each year. Water biogeochemistry of rivers is a critical indicator of hydrologic e...