The recent completion of drilling at Vostok station in East Antarctica has allowed the extension of the ice record of atmospheric composition and climate to the past four glacial–interglacial cycles. The succession of changes through each climate cycle and termination was similar, and atmospheric and climate properties oscillated between stable bounds. Interglacial periods differed in temporal evolution and duration. Atmospheric concentrations of carbon dioxide and methane correlate well with Antarctic air-temperature throughout the record. Present-day atmospheric burdens of these two important greenhouse gases seem to have been unprecedented during the past 420,000 years.

Climate and atmospheric history of the past 420,000 years from the Vostok ice core, Antarctica

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Studies of ecosystem processes on the Jornada Experimental Range in southern New Mexico suggest that longterm grazing of semiarid grasslands leads to an increase in the spatial and temporal heterogeneity of water, nitrogen, and other soil resources. Heterogeneity of soil resources promotes invasion by desert shrubs, which leads to a further localization of soil resources under shrub canopies. In the barren area between shrubs, soil fertility is lost by erosion and gaseous emissions. This positive feedback leads to the desertification of formerly productive land in southern New Mexico and in other regions, such as the Sahel. Future desertification is likely to be exacerbated by global climate warming and to cause significant changes in global biogeochemical cycles.

https://science.sciencemag.org/content/sci/247/4946/1043.full.pdf

Biological Feedbacks in Global Desertification

The International Atomic Energy Agency (IAEA), in cooperation with the World Meteorological Organization (WMO), has been conducting a world-wide survey of hydrogen (H/'H) and oxygen (O/O) isotope composition of monthly precipitation since 1961 At present, 72 IAEA/WMO network stations are in operation Another 82 stations belonging to national organizations continue to send their results to the IAEA for publication The paper focuses on basic features of spatial and temporal distribution of deuterium and O in global precipitation, as derived from the IAEA/WMO isotope database The internal structure and basic characteristics of this database are discussed in some detail The existing phenomenological relationships between observed stable isotope composition of precipitation and various climate-related parameters such as local surface air temperature and amount of precipitation are reviewed and critically assessed Attempts are presented towards revealing interannual fluctuations in the accumulated isotope records and relating them to changes of precipitation amount and the surface air temperature over the past 30 years

Isotopic Patterns in Modern Global Precipitation

[1] The analysis of univariate or multivariate time series provides crucial information to describe, understand, and predict climatic variability. The discovery and implementation of a number of novel methods for extracting useful information from time series has recently revitalized this classical field of study. Considerable progress has also been made in interpreting the information so obtained in terms of dynamical systems theory. In this review we describe the connections between time series analysis and nonlinear dynamics, discuss signal-to-noise enhancement, and present some of the novel methods for spectral analysis. The various steps, as well as the advantages and disadvantages of these methods, are illustrated by their application to an important climatic time series, the Southern Oscillation Index. This index captures major features of interannual climate variability and is used extensively in its prediction. Regional and global sea surface temperature data sets are used to illustrate multivariate spectral methods. Open questions and further prospects conclude the review.

/pdf/advanced-spectral-methods-for-climatic-time-series-4hxv68i0r0.pdf

Advanced spectral methods for climatic time series

During much of the Quaternary, the Earth's climate has undergone drastic changes most notably successive glacial and interglacial episodes. The past 150 kyr includes such a climatic cycle: the last interglacial, the last glacial and the present holocene interglacial. A new climatic–time series for this period has been obtained using δ18 O data from an Antarctic ice core.

A 150,000-year climatic record from Antarctic ice

Methane measurements along the Vostok ice core reveal substantial changes over the past 160,000 years which are associated with climate fluctuations. These results point to changes in sources of methane and also show that methane has probably contributed, like carbon dioxide, to glacial-interglacial temperature changes.

Ice-core record of atmospheric methane over the past 160,000 years

THE2,083-m Vostok ice core recovered by the Soviet Antarctic expeditions has provided much information of climatic and environmental interest, for a period covering a full glacial–inter-glacial cycle1–6. Here we present and discuss the dust record obtained down to 2,202 m, the final depth to which this core was extended in 1986. First, we document the fact that major changes in aeolian deposits, as recorded in the Vostok core, appear to be of global significance and confirm the existence of a link between high-latitude aeolian deposits and the Earth's orbital parameters7,8. Second, we propose atmospheric dust as a strati-graphic marker to compare timing with other records of palaeocli-mate, and use the magnetic-susceptibility profile measured along the RC11-120 Indian Ocean core9 for this purpose, assuming that major dust events correspond to common aeolian inputs. This approach indicates that the Vostok and marine records were roughly in phase at the previous glacial–interglacial transition.

Palaeoclimatological and chronological implications of the Vostok core dust record

Interpretation of the past CO 2 variations recorded in polar ice during the large climatic transitions requires an accurate determination of the air-ice age difference. For the Vostok core, the age differences resulting from different assumptions on the firn densification process are compared and a new procedure is proposed to date the air trapped in this core. The penultimate deglaciation is studied on the basis of this new air dating and new CO 2 measurements. These measurements and results obtained on other ice cores indicate that at the beginning of the deglaciations, the CO 2 increase is either in phase or lags by less than about 1000 years with respect to the Antarctic temperature, while it clearly lags the temperature at the onset of the last glaciation. DOI: 10.1034/j.1600-0889.1991.t01-1-00002.x

https://onlinelibrary.wiley.com/doi/pdf/10.1034/j.1600-0889.1991.t01-1-00002.x

CO2-climate relationship as deduced from the Vostok ice core: a re-examination based on new measurements and on a re-evaluation of the air dating

Vostok climate and CO2 records suggest that CO2 changes have had an important climatic role during the late Pleistocene in amplifying the relatively weak orbital forcing. The existence of the 100-kyr cycle and the synchronism between Northern and Southern Hemisphere climates may have their origin in the large glacial–interglacial CO2 changes.

Y. S. Korotkevich

Papers

A 150,000-year climatic record from Antarctic ice

Ice-core record of atmospheric methane over the past 160,000 years

Palaeoclimatological and chronological implications of the Vostok core dust record

CO2-climate relationship as deduced from the Vostok ice core: a re-examination based on new measurements and on a re-evaluation of the air dating

Vostok ice core: climatic response to CO2 and orbital forcing changes over the last climatic cycle