Showing papers on "Climate change published in 1983"

Global Vegetation and Land Use: New High-Resolution Data Bases for Climate Studies

Abstract: Global vegetation and land-use data bases (1° latitude by 1° longitude resolution), designed for use in studies of climate and climate change, were compiled in digital form drawing upon approximately 100 published sources complemented by a large collection of satellite imagery. The vegetation data were encoded using the UNESCO classification system; land-use data were encoded using a classification system developed by the author. The vegetation and land-use data were then integrated into a land-cover data base. Areal estimates for most ecosystems from the land-cover data base were found to be significantly different from areal estimates derived from two other global land-cover sources. Possible explanations for discrepancies among these data bases include differences in ecosystem definitions and source material used in compilation. From areal estimates of major ecosystems, derived from the new vegetation and land-cover data bases it is estimated that the total ecosystem reduction caused by agricu...

Climate History and the Modern World

Abstract: H. H. Lamb's latest book on the earth's changing climate is a carefully crafted work covering four areas: the physical basis of climate and climate change, the methods of climate reconstruction, the history of climate since the height of the last glaciation, and the impact of climate on human affairs. The book will be of particular interest to three groups. Atmospheric scientists interested in the long history of climate behavior (but perhaps overwhelmed by Lamb's all-encompassing work on the topic, Climate: Past, Present and Future, vol. II, Methuen, New York), will find Climate History and the Modern World to be a good titration of the fuller work. Scientists in other fields, including social scientists grappling with issues of climate-society interaction, will find the book a good entree into the field. Finally, Lamb himself suggests that the book will be useful to resource managers and other decision makers trying to avoid negative climate impacts. With this last audience in mind, no doubt, Lamb has chosen a style that eschews extensive footnoting and references (though sufficient citations are included to lead to further information). This works quite well and seems reasonable in view of his carefully documented previous writings.

Evidence from north-west Canada for an early Holocene Milankovitch thermal maximum

Abstract: According to the Milankovitch theory of global climatic change, maximum summer solar radiation at high latitudes of the Northern Hemisphere occurred at 10,000 yr BP (refs 1, 2). In particular, it predicts summer solstice radiation greater by 9–10%. Preliminary climate simulation experiments with these increased values of radiation confirm that high-latitude land surfaces received maximal insolation at ∼10,000 yr (refs 3, 4). Paradoxically, however, the large volume of fossil pollen and other evidence from North America indicates a maximum of Holocene warmth at 7,000–6,000 yr (ref. 5), and a recent review of the evidence from New England suggests that the warming began at 9,000 and ended at 5,000 yr, but also stresses the difficulties of interpretation in terms of climate change6. We summarize here data from sites in the north-west corner of mainland Canada (Fig. 1) that directly support the Milankovitch hypothesis.

The spatial and temporal characteristics of northern Hemisphere surface air temperature variations

Abstract: Variations in temperature over landmasses during the present century are determined. The spatial patterns of change accompanying major warming and cooling episodes are mapped. The spatial representativeness of the Northern Hemisphere average is assessed and implications for proxy climate studies are considered. Finally, the seasonal breakdown of trends and correlations between monthly and annual data for the Arctic and Northern Hemisphere is considered.

Projecting future sea level rise : methodology, estimates to the year 2100, and research needs

Abstract: Concentrations of atmospheric CO/sub 2/ and other greenhouse gases will continue to increase in coming decades. Two National Academy of Sciences panels have concluded that higher levels of these gases will almost certainly produce a large global warming. That warming, by thermally expanding the oceans and by causing the transfer of ice and snow resting on land to the oceans, should raise sea level substantially faster than the rise that has taken place during the past century. Although current knowledge is inadequate to make a precise prediction of future sea level rise, it is sufficient to predict the likely range. Many factors were considered in generating the estimates of sea level rise contained in this report: population and productivity growth, atmospheric and climatic change, and oceanic and glacial response. High and low assumptions for these principal determinants of sea level rise were derived from the literature. When linked together the various assumptions allowed the estimation of high and low paths of future sea level rise. 88 references.

Ice and Snow Feedbacks and the Latitudinal and Seasonal Distribution of Climate Sensitivity

Abstract: A new parameterization of snow and ice area and albedo as functions of surface temperature is presented based on recent satellite observations of snow and ice extent. This parameterization is incorporated into a seasonal energy-balance climate model. Experiments are conducted with the model to determine the effects of this parameterization change on the latitudinal and seasonal distribution of model sensitivity to external forcings of climate change, such as solar constant variations and changes in the atmospheric carbon dioxide amount. The sea ice-thermal inertia feedback is found to be the determining factor in this sensitivity pattern, producing enhanced sensitivity in the polar regions in the winter and decreased sensitivity in the polar regions in the summer. The albedo feedbacks (snow-area and snow/ice-meltwater) are weak and produce a small amount of additional sensitivity, but do not change the pattern. The response pattern is the same as that found by Manabe and Stouffer (1980) with a ge...

The role of sea ice in climatic variability: Theories and evidence 1

Abstract: The climatic role of sea ice is assessed in a survey of the recent literature. Theoretical or model‐based results are compared with existing evidence of ice‐atmosphere interactions over scales ranging from the local and regional to the hemispheric and global. The evidence shows that sea‐ice fluctuations are meteorologically important locally, primarily through associations with air temperature. On the regional and hemispheric scales, atmospheric and sea‐ice fluctuations are correlated according to both observational evidence and model experiments. While the causal links have not been evaluated quantitatively, there is evidence that the stronger signal occurs in the response of the ice to the atmosphere. On the longer time‐scales, model experiments and qualitative arguments suggest that sea ice may play a major role in the climatic change. However, the results of large‐scale coupled model simulations contain deficiencies and must be viewed with caution pending more realistic treatments of sea‐ice ...

Isotopic evidence for the past climates and vegetation of southern Africa

Abstract: The stable isotopes of hydrogen, oxygen and carbon can potentially provide evidence of past climates. The most detailed information has been obtained from variations in the oxygen-18 content of foraminifera from ocean floor cores, the analysis of which has produced a record of ocean temperature changes through the Quaternary and beyond. The use of isotope analysis of continental materials to reveal climatic change is more limited, but some advances have been made in recent years. One approach has been to utilize the variations in the isotopic composition of precipitation as recorded in ancient groundwater. Thus groundwater samples from a confined aquifer on the southern Cape coast show a marked rise in temperature since the Last Glacial maximum. The temperature changes during the Upper Pleistocene and Holocene are also reflected in the oxygen-18 content of stalagmites from the Cango caves in the same region. The widespread occurrence of C4 grasses in the warmer summer rainfall areas of southern Africa provides a novel possibility of observing temporal shifts of climatic boundaries. The distinctly high carbon-13 content of C4 plants is clearly reflected in the skeletons of grazers so that faunal material from suitably situated archaeological sites can be used to observe changes in the composition of the local grass-cover. The evidence thus far accumulated suggests only minor changes since the Upper Pleistocene. The combined evidence to date indicates that temperatures and also precipitation in southern Africa have changed since the Last Glacial maximum, about 18 000 years ago, but that shifts in the boundaries of the various veld-types were probably not very extensive.

Radiocarbon-dated evidence of worldwide early Holocene climate change

Abstract: Radiocarbon-dated glacial deposits from several different areas of the world indicate that alpine glaciers and ice caps in parts of both the Northern and Southern Hemispheres expanded in response to climate change in early Holocene time. These data suggest that a worldwide episode of cooler climate similar in scope to the more recent Neoglaciation occurred ca. 8,500−7,500 yr B.P.

Carbon Dioxide and Climatic Change

Abstract: Publisher Summary This chapter reviews some of the carbon dioxide–climate sensitivity studies to analyze effect of carbon dioxide on climate. The carbon dioxide-induced change of the atmospheric temperature is analyzed based upon the results from radiative, convective models of the atmospheric-surface system. A general circulation model of climate is elaborated as a prognostic system of equations representing the physical and dynamical processes, which control climate. A brief description of climate as simulated by the Manabe–Stouffer model is presented. The climatic effect of the increase in carbon dioxide concentration is discussed based upon analysis of the differences between the two statistically stationary states which emerge from the 1×CO 2 and 4×CO 2 experiments. The distribution of the carbon dioxide-induced change in a global model climate is discussed. The latitudinal and seasonal variation of the signal-to-noise ratio for the carbon dioxide-induced change of zonal mean surface air temperature over continents is also illustrated.

Recent climatic change in Australia: Implications for a CO2-warmed earth

Abstract: A significant change in mean precipitation occurred over much of Australia between 1913–45 and 1946–78. This is described on a seasonal basis and related to possible changes in the atmospheric circulation. It now appears that during this time mean surface temperatures in the mid southern latitude zone increased by up to 1 °C. This temperature change could be at least partly due to an increase in atmospheric CO2 concentrations from about 260 ppmv in the early nineteenth century. In any case the observed temperature increase is similar to the predicted future effects of a 50% increase in atmospheric CO2 concentrations. Thus the climatic change which occurred earlier this century is at least a good analogy for the effects of a CO2-induced global warming which is expected to occur over a similar time interval in the future. This allows the construction of more detailed and quantitative climate scenarios. The most noteworthy conclusion is that marked changes in the seasonally of precipitation should be anticipated, with seasonal changes in some areas being of the order of 50% or more for a doubling of CO2 content. The results are in general consistent with earlier more qualitative scenarios for Australia.

Social science research and climate change : an interdisciplinary appraisal

Abstract: I. Research in Climate Change and Society: Two Perspectives.- to Part I.- Setting New Research Agendas: A Social Scientist's View.- CO2, Climate and Society: A Brief Overview.- II. Research in Climate Change and Society: Individual Contributions.- to Part II.- Societal Response to CO2-induced Climate Change: Opportunities for Research.- Climate Society in History: A Research Agenda.- Research on Political Institutions and Their Response to the Problem of Increasing CO2 in the Atmosphere.- International Legal and Institutional Implications of an Increase in Carbon Dioxide: A Proposed Research Strategy.- Psychological Dimensions of Climatic Change.- Anthropological Perspectives on Climate Change.- Interdisciplinary Research and Integration: The Case of CO2 and Climate.

Postglacial climatic change: vegetation dynamics and the pollen record

Abstract: In this report I review some recent developments in Holocene terrestrial palaeoclimate mapping from pollen data, and related work concerning the underlying processes of vegetational response to climatic change. Topics discussed include synoptic pollen mapping, pollen-climate transfer functions, migrational lags, mosaic phenomena, forest-succession simulations, and the response of vegetation systems to the frequency spectrum of climatic variability. Most of the work cited is from temperate regions, where the pollen record is most prolific; and specifically from Europe and eastern North America where by far the most data exist. Given the current controversy over the determination of Holocene vegetational changes, I have focused the discussion on principles, hypotheses and new directions.

Abrupt Climate Changes

Abstract: Abrupt climatic changes have been revealed by many continental and marine palaeoclimatic records. However, coring disturbances, dating uncertainties, sedimentary hiatuses and particular problems related to the indicators of past climates impede estimation of the time span of such abrupt climatic transitions.

Monsoon Rains of the Late Pleistocene and Early Holocene: Patterns, Intensity and Possible Causes of Changes

Abstract: Field evidence for marked environmental changes in the regions subject to monsoon climate has long been available: ancient lake shorelines, fossil dunes, evaporites and Alpine moraines (Brooks 1926, Zeuner 1946). However, a clear picture of the spatial patterns of these features and an accurate radiocarbon-dated chronology of events has been lacking. Without information on the pattern and timing of events, it has been difficult to characterize and interpret these environmental changes in terms of circulation patterns and climate. Moreover, it has been difficult to test hypotheses that attempt to explain the changing monsoon climates. This paper summarizes recent studies that have provided sufficient information about the nature, location and timing of climatic events to facilitate reconstruction of the changes in monsoonal circulations and estimation of the magnitude of precipitation changes. The possible role of changes in the Earth’s orbital elements (obliquity, precession and eccentricity) in causing the observed climatic changes is examined. Some early ideas on the astronomical theory of climatic change, as it relates to tropical climates, are traced.

Response of the North American corn belt to climatic warming

Abstract: The climate of the North American corn belt was characterized as part of an effort to estimate the effects of climatic change on that agricultural region. Heat and moisture characteristics of the current corn belt were first identified. Locations of those characteristics were then mapped, based on a climate simulated to result from doubling the amount of atmospheric CO/sub 2/. Such projections of corn-belt location were made both with and without allowance for earlier planting dates under a warmer climate. Because the direct effects of CO/sub 2/ on plants, improvements in farm technology, and plant breeding are not considered, the resulting projections represent an extreme or worst case. Results indicate that even for such a worst case, climatic conditions favoring corn production would not extend very far into Canada. Greatest translocations are projected for the western, or driest, part of the corn belt where other crops such as winter wheat could replace corn. However, this kind of exercise clearly shows that the use of climate-model output requires several highly questionable assumptions about changes in the timing and regional distribution of precipitation accompanying a climatic warming. Increased use of climatic data and improved specification of CO/sub 2/-induced increases in water-use efficiencymore » of corn are suggested for more credible projections of corn-belt responses to increasing CO/sub 2/.« less

Climatic effects of atmospheric carbon dioxide

Abstract: This response to a letter re-emphasizes the purpose of the Workshop on the First Detection of Carbon Dioxide Effects which, was to outline a research and analysis program that would provide the information needed to address more completely the issue of CO/sub 2/ warming of the environment and to determine ... whether or not (the climate models) may be grossly in error. The approach proposed by the Workshop participants indicated that definitive conclusions about climatic change should be based on correlated changes in an array of variables, rather than on selected changes in any single variable. A three-pronged effort was outlined to accomplish this objective.

The relationships between tree rings of qilianshan juniper and climatic-change and glacial activity during the past 1000 years in china

Abstract: The climatic history of China during recent centuries are not known in detail, though there exist many indirect evidences of the significant climatic change. Dendroclimatic analysis presents a very promising method to acquire information on the chronology and

A review of climate models and their simulation of CO2‐induced warming

Abstract: The characteristics of the different types of climate models are reviewed and are tabulated for the model simulations of CO2‐induced climatic change. These simulations are discussed in terms of the surface temperature change and the response times of the atmosphere, oceanic mixed layer and deep ocean. A calculation of the time‐dependent warming resulting from a time‐dependent increase in atmospheric CO2 is performed with a simple climate model, and is used to estimate the time of first detectability of the warming signal. Considering the decrease in the climatic noise level with increasing averaging period during the past century and the increase in signal with time in the future, it is found that the time of first detectability is relatively insensitive to the averaging period from 10 to 40 years. However, the time of first detectability is found to be uncertain by about ±10 years due to the uncertainty in the rate at which heat is exchanged between the oceanic mixed layer and deeper ocean. It is recomme...

Identification and characterization of watershed models for evaluation of impacts of climate change on hydrology

Abstract: There is growing concern that increases in the ambient concentration of atmospheric CO/sub 2/ will effectuate a significant change in the distribution of global precipitation as global temperatures rise. The identification and characterization of rainfall/snowmelt-runoff modeling capability is conducted to research the effects of a carbon dioxide-induced climate change on hydrology. To understand the effects of climate change on the supply and use of freshwater resources, it is necessary to understand the effects of climate change on hydrology, particularly runoff. The three general categories of watershed models reviewed are transfer functions, lumped parameter models, and distributed parameter models. Within each general classification specific watershed models that are publicly available and implementable on digital computers are reviewed in detail. Key factors in the model characterization are the component hydrologic processes, if any, each model addresses along with its climatology/meteorology-related input data requirements. Assumptions are made regarding the probable circumstances surrounding the application of watershed models to the analysis of climate change on hydrology. Based on these assumptions, in relation to the characteristics of the models, a subset of watershed models that appears suited for the evaluation of the impacts of climate change on hydrology was determined. 17 references, 2 figures, 6more » tables.« less

The Physical Basis of Climate Modelling

Abstract: Over the past decade, three-dimensional models of the general circulation have been used extensively to study climate and climate change. The use of such models is limited to a few research groups. This paper is intended to clarify the physical principles which are used to formulate numerical models of climate, to indicate the confidence which can be placed in the parametrizations, and to provide guidance on the use of models in climate studies. A climate model should represent the interaction of the atmosphere, ocean, sea-ice and land-ice and the land surface. Until recently, most three-dimensional models used for climate studies consisted of general circulation models of the atmosphere, with an interactive land surface, and prescribed sea surface temperatures and sea ice extents. Hence, this paper is mainly concerned with general circulation models of the atmosphere.