Past Global Changes Research Articles

Pleistocene climate change, natural environments and palaeolithic occupation of the Angara–Baikal area, east Central Siberia

Palaeogeographical and palaeoenvironmental evolution throughout the Baikal territory during the Quaternary Period is characterized by the interaction of past global climatic changes and the regional topographic alteration by the neotectonic activity of the Mongolian–Siberian mountain zone. The specific geomorphological character of the Baikal topography governed by sub-rifting orogenic regimes gave rise to a variety of natural settings and landscapes throughout the Pleistocene. An increased accumulation rare of sub-aerial sediments, a broader genetic variety of palaeosol horizons and periglacial surface deformations attest to a progressing climatic continentality during the Late Quaternary. Marked climatic shifts characterize the last glacial–interglacial cycle, with the major glaciations in the East Siberian mountains during the cold (OIS 4 and 2) stages. The mid-last glacial (OIS 3) climatic optimum (dated to 31 ka BP) was thermally approaching the last interglacial (OIS 5e) conditions. Palynological and palaeontological, as well as early cultural data, provide evidence of strongly fluctuating Late Pleistocene climatic variations. Diversity of the palaeolithic records attest to several stages of early human occupation, with the earliest (late Middle Pleistocene) represented by pebble tool industries. Contextual association of the Middle Pleistocene artefacts of the Levallois tradition with the early Last Glacial aeolian sands implies cultural adaptation to cold periglacial environments. Systematic multidisciplinary investigations at chronologically and contextually well-fixed palaeolithic sites provide additional multi-proxy information on the Pleistocene climate change and the dominant geomorphic processes over the particular geographic area. Reconstruction of the evolutionary pathways and processes in the natural environments, the specific material-technological conditions and the production level of the early human communities, as well as documentation of climatic events stored in the geological record are the principal study objectives of the current geoarchaeological studies in the Baikal sector of Siberia.

Past Global Changes and Their Significance for the Future

Past Global Changes and Their Significance for the Future

The Magnitude and Rate of Past Global Climate Changes

The earth's climate is constantly changing and currently warming. This paper is an evaluation of previous climate changes intended to test the validity of assigning causality to human activity. Records of glacial advances and retreats indicate changes in relative summer temperature. Lacustrine and subaerial sediments afford a record of glacier advances and retreats from the end of the Pleistocene. Palynology offers a record of species succession in response to climate changes. Dendrochronology indicates summer temperature. Isotope paleontology provides a measurement of temperature at the time of marine sediment deposition. Isotopic evaluation of continental ice is an indicator of temperature at the time of precipitation. Anthropologic sources provide significant climate data, such as information about villages overrun by glaciers, open-ocean iceberg density, or harbors filled with ice. Available sources record continual changes in climate. The temperature lowered 15 to 20°C from the Paleocene to the Neogene. Another 10°C change occurred in the Pleistocene. Correlative data from North America, Greenland, and Scandinavia indicate many climate changes were global in scope. It is difficult to develop precise paleothermometry, but qualitative evaluations indicate sudden and dramatic changes in climate. Some changes are perhaps as great as a change from conditions warmer than today, to a full glacial climate in as little as 100 years. The converse can be true. Current data indicate a trend of change that is severe but no greater in rate or magnitude, and probably less in both, than many changes that have occurred in the recent geologic past.

Past global changes and their significance for the future K. D. ALVERSON, F. OLDFIELD and R. S. BRADLEY (eds) Publisher Pergamon, Oxford 2000; Quaternary Science Reviews (vol. 19, no. 1–5) (479pp) Journal version US$57/DFL 124 Hardcover US$64/DFL,139

Journal of Quaternary ScienceVolume 15, Issue 6 p. 657-658 Book Review Past global changes and their significance for the future K. D. ALVERSON, F. OLDFIELD and R. S. BRADLEY (eds) Publisher Pergamon, Oxford 2000; Quaternary Science Reviews (vol. 19, no. 1–5) (479pp) Journal version US$57/DFL 124 Hardcover US$64/DFL,139 Chris Turney, Chris Turney Department of Geography, Royal Holloway, Egham, Surrey TW20 0EY, EnglandSearch for more papers by this author Chris Turney, Chris Turney Department of Geography, Royal Holloway, Egham, Surrey TW20 0EY, EnglandSearch for more papers by this author First published: 05 September 2000 https://doi.org/10.1002/1099-1417(200009)15:6<657::AID-JQS553>3.0.CO;2-0AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume15, Issue6September 2000Pages 657-658 RelatedInformation

Book Review: Past global changes and their significance for the future

Book Review: Past global changes and their significance for the future

Past Global Changes and their Significance for the Future

Past Global Changes and their Significance for the Future

PAGES — Past Global Changes and their Significance for the future: an Introduction

PAGES — Past Global Changes and their Significance for the future: an Introduction

Past global changes and their significance for the future K. D. ALVERSON, F. OLDFIELD and R. S. BRADLEY (eds) Publisher Pergamon, Oxford 2000; Quaternary Science Reviews (vol. 19, no. 1-5) (479pp) Journal version US$57/DFL 124 Hardcover US$64/DFL,139

Journal of Quaternary ScienceVolume 15, Issue 6 p. 657-658 Book Review Past global changes and their significance for the future K. D. ALVERSON, F. OLDFIELD and R. S. BRADLEY (eds) Publisher Pergamon, Oxford 2000; Quaternary Science Reviews (vol. 19, no. 1–5) (479pp) Journal version US$57/DFL 124 Hardcover US$64/DFL,139 Chris Turney, Chris Turney Department of Geography, Royal Holloway, Egham, Surrey TW20 0EY, EnglandSearch for more papers by this author Chris Turney, Chris Turney Department of Geography, Royal Holloway, Egham, Surrey TW20 0EY, EnglandSearch for more papers by this author First published: 05 September 2000 https://doi.org/10.1002/1099-1417(200009)15:6<657::AID-JQS553>3.0.CO;2-0AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinked InRedditWechat No abstract is available for this article. Volume15, Issue6September 2000Pages 657-658 RelatedInformation

Long Term Climate Records from Polar Ice

One of the great challenges in climate research is to investigate the principal mechanisms that control global climatic changes and an effective way to learn more about it, is the reconstruction of past climate changes. The most important sources of information about such changes and the associated composition of the atmosphere are the two large ice caps of Greenland and Antarctica. Analysis of ice cores is the most powerful means we have to determine how climate has changed over the last few climatic cycles, and to relate this to changes in atmospheric composition, in particular to concentrations of the principal greenhouse gases – CO2, CH4 and N2O (carbon dioxide, methane, and nitrous oxide). Transitions from cold ice age climates to warmer interstadials have always been accompanied by an increase of the atmospheric concentration of the three principal greenhouse gases. This increase has been, at least for CO2, vital for the ending of glacial epochs. A highly simplified course of events for the past four transitions would then be as follows: first, changing orbital parameters initiated the end of the glacial epoch; second, an increase in greenhouse gases then amplified the weak orbital signal; third, in the second half of the transition, warming was further amplified by decreasing albedo, caused by melting of the large ice sheets in the Northern Hemisphere going parallel with a change of the ocean circulation. The isotopic records of Greenland ice cores show evidence for fast and drastic climatic changes during the last glacial epoch. Possible causes and mechanisms of such changes and their significance as global climatic events are discussed here. Ice core results also enable the reaction of the environment to past global changes to be investigated. It will also be discussed how reliable stable isotope records are as a local temperature proxy and how representative paleoclimatic results from Greenland and Antarctica are in relation to global climate.

Past global changes and their significance for the future

Placing the short instrumental record of climate into a longer-term perspective provides valuable insights into the envelope of climate variability on timescales of significance to society today. Numerous paleotemperature records reveal that the 20th century has been exceptionally warm in the context of the last millennium, and perhaps many millennia. Furthermore, the coldest decades of the last century (the nadir of the “Little Ice Age”) were among the coldest times in the late Holocene. Thus, the world has experienced both the warmest and the coldest extremes of the late Holocene within a brief interval of less than 200 years. Extending the climate record back in time enables the underlying forcing factors (prior to global-scale anthropogenic effects on the climate system) to be identified. Paleoclimatic data are essential to obtain a comprehensive understanding of the climate system, without which reliable forecasting of future conditions will not be possible.

Abstract: The magnitude and rate of past global climate changes

Abstract: The magnitude and rate of past global climate changes

New progress of lake sediments and environmental changes research in China

Environmental change recorded by lake sediments is one of the important branches of the past global changes study. The new progress of lake sediments and environmental changes in China since the late 1980s has been comprehensively discussed. The highlights emphasized are Asian paleomonsoon migration reflected by lake level fluctuation, uplift of the Qinghai-Xizang Plateau recorded by lacustrine sediments, saltlake sediments and environmental evolution, lake response to the natural-human interaction and modern lake biogeochemical process. Meanwhile important suggestions for the lake sediments and environmental research in the future are proposed, which include studies on the quantitative relationship between lake environment proxies and climate factors, high-resolution evolutionary sequence and spatial differentiation of environments, modern lake dynamic process and environment, Quaternary Chinese lake database and global changes.

Rate and Magnitude of Past Global Climate Changes

Abstract Existing data indicate that the Earth’s climate is probably warming. Politicians and the media typically assume this warming is the result of human activity. This article summarizes previous climate changes to test the validity of assigning causality to human activity. Records of glacial advances and retreats indicate relative summer temperature. Lacustrine and subaerial sediments afford a record of glacier advances and retreats from the Pleistocene to the present time. Palynology offers a record of species succession in response to climate changes. Dendrochronology is another indicator of summer temperature. Isotope paleontology offers a measurement of temperature at the time of marine sediment deposition, and isotopic evaluation of continental ice is an indicator of temperature at the time of precipitation. Anthropologic sources contain significant climate data such as information about villages overrun by glaciers, open-ocean iceberg density, or harbors filled with ice. Today, scientists are capable of direct measurement of climatic conditions. These sources record continual changes in climate. Broadly, the temperature changed 15 to 20°C from the Paleocene to the Neogene. Perhaps, there was as much as another 10°C change in the Pleistocene. Correlative data from North America, Greenland, and Scandinavia indicate many climate changes were truly global in scope. Although it is difficult to develop precise paleothermometry, qualitative evaluations indicate sudden and dramatic changes in climate. Some are perhaps as great as a change from conditions warmer than today to a full glacial climate in as little as 100 years. The converse can be true. Current data indicate a trend of change that is substantially severe but no greater in rate or magnitude, and probably less in both, than many changes that have occurred in the past.

Abstract: The Rate and Magnitude of Past Global Climate Changes&amp;nbsp;

Abstract: The Rate and Magnitude of Past Global Climate Changes&amp;nbsp;

Researchers investigate inter‐hemispheric climate linkages in the Americas and their societal effects

Records from the past document natural climate variability on all timescales, from seasons to decades to centuries. Documenting and understanding the nature and cause of past climate variability is the key to predicting future climate change, especially since climate will continue to change in response to humankind's impact on the environment.The International Geosphere‐Biosphere Program on Past Global Change (IGBP‐PAGES) is providing global evidence of natural climate variability and its forcing to establish a framework that will help society and decision‐makers prepare for future change. Because no single record can adequately represent past global climate change, regional paleoclimate evidence from both the ocean and land must be assembled and integrated. Within IGBP‐PAGES, the Pole‐Equator‐Pole Paleoclimate of the Americas (PEP 1) initiative attempts to provide an interhemispheric view by focusing on the integration of paleoclimate data along a longitudinal transect in the western hemisphere [PAGES, 1995].

Proposed drilling program backed in China

Chinese paleoenvironmental experts and their international colleagues enthusiastically supported a proposed East Asian Continental Drilling Program (EACDP) for environmental sciences at a recent gathering. The proposed program, discussed at the 77th Xiangshan Scientific Conference, originated in the Chinese Academy of Sciences. It is a national‐scale effort that addresses recent recommendations of international scientific organizations such as the Intergovernmental Panel on Climate Change, the Past global Changes project of the International Geosphere‐Biosphere Program, and the International Continental Scientific Drilling Program. In scale and paleoenvironmental focus, the program would be unique, helping to resolve some basic evolutionary environmental questions and providing an example that might be emulated in other parts of the world.

Response of the Ocean/Atmosphere System to Past Global Changes: An Introduction to IGCP Project 386

Response of the Ocean/Atmosphere System to Past Global Changes: An Introduction to IGCP Project 386

Making our contributions to past global change

IN recent years, a series of environmental problems have attracted wide attention in the world.As environmental changes can result from both the operations of natural factors and human ac-tivities, the international science community has the common opinion that environmental prob-lems should be studied in a broader perspect. In other words, the earth environment should beregarded as an entity that consists of many interactive and interrelated parts. Highlighted by

Climatic instability record during the Penultimate Glaciation: Evidence from Huining loess

THE investigations of past global changes reveal strong climatic instability during the lastglaciation. Most terrestrial palaeoclimate records have not given climatic conditionclues in the Penultimate Glaciation. It is very necessary for us to know whether the climaticinstability picture is a particular phenomenon occurring only in the last glacial period. In this

Evolution of Quaternary groundwater system in North China Plain

The Quaternary groundwater system in the North China Plain is formed mainly through the terrestrial water flow action on the united geological and tectonic backgrounds. The analysis of groundwater dynamic field, simulation of groundwater geochemistry, and the14C dating and extraction of isotope information have provided more evidence for recognizing and assessing the evolution of groundwater circulation system and studying the past global changes. The exploitation and utilization of groundwater on a large scale and overexploitation have given rise to the decline of regional groundwater level, change of flow field, decrease of water resources and downward movement of saline water body. The water environment has entered a new evolution stage in which it is intensely disturbed by the mankind’s activities.