Showing papers on "Climate change published in 1980"

On the Distribution of Climate Change Resulting from an Increase in CO2 Content of the Atmosphere

Abstract: A study of the climatic effect of doubling or quadrupling of CO2 in the atmosphere has been continued by the use of a simple general circulation model with a limited computational domain, highly idealized geography, no seasonal variation of insolation, and a simplified interaction between cloud and radiative transfer. The results from the numerical experiments reveal that the response of the model climate to an increase of CO2 content in air is far from uniform geographically. For example, one can identify the high-latitude region of the continent where the runoff rate increases markedly, a zonal belt of decreasing soil moisture around 42° latitude, and a zone of enhanced wetness along the east coast of the subtropical portion of the model continent. The general warming and the increase of moisture content of air, which results from a CO2 increase, contributes to the large reduction of the meridional temperature gradient in the lower model troposphere because of 1) poleward retreat of highly refl...

Solar variability and climatic change during the current millennium

Abstract: Claims of a Sun–weather relationship1 can only be evaluated properly when the history of solar change is known in detail. The most obvious feature of solar variability is the change over time in the number of sunspots on the visible half of the Sun. A less visible indicator of solar change is the 14C content of tree rings. The atmospheric 14C levels derived from tree ring measurements can be tied to the Sun's modulation of the cosmic ray flux in the vicinity of the Earth, and thus provide a history of solar change2. We report here a comparison of climate records with the record of solar change obtained from atmospheric 14C variations. This yielded ‘negative’ results, that is, a relationship between the climatic time series and the 14C derived record of solar change could not be confirmed.

Detecting Climate Change due to Increasing Carbon Dioxide

Abstract: The observed interannual variability of temperature at 60°N has been investigated. The results indicate that the surface warming due to increased carbon dioxide which is predicted by three-dimensional climate models should be detectable now. It is not, possibly because the predicted warming is being delayed more than a decade by ocean thermal inertia, or because there is a compensating cooling due to other factors. Further consideration of the uncertainties in model predictions and of the likely delays introduced by ocean thermal inertia extends the range of time for the detection of warming, if it occurs, to the year 2000. The effects of increasing carbon dioxide should be looked for in several variables simultaneously in order to minimize the ambiguities that could result from unrecognized compensating cooling.

Stable isotope and sea-level data from New Guinea supports Antarctic ice-surge theory of ice ages

Abstract: Two theories of glaciation have received considerable attention, the Milankovitch orbital theory1,2 in which climatic change is ascribed to latitude-dependent variations in solar radiation that accompany changes in the Earth's orbital parameters, and the Antarctic surge hypothesis3–6, in which a large Antarctic ice sheet ‘surges’ into the Southern Ocean thereby increasing the Earth's albedo, and the resultant cooling triggers the growth of ice in the Northern Hemisphere. The interval which encompasses the peaks of the last interglacial maximum at ∼125 kyr (ref. 7) and its subsequent decline, with cooling of the North Atlantic8 and rapid fall of sea level9,10, presumably also includes the event that triggered the succeeding ice age. The raised coral reefs of Huon Peninsula, Papua New Guinea, contain a particularly good record of the interval 140–105 kyr (ref. 11), from which we present oxygen isotope and sea-level data which seem to require an Antarctic surge at 120 kyr, and which also have a bearing on the role of the Milankovitch factor.

Past Climate Reconstructed from Tree Rings

Abstract: Past Climate Reconstructed from Tree Rings Three severely cold winters over the greater part of the United States accompanied by droughts in the first year, and high precipitation in the following two years, suggest to the layman that either our ideas of "normal" climatic conditions are wrong or that climate is changing. Although the evidence for an actual climatic change continues to be-vigorously debated, past climate was at least more variable than our present climate. Consequently, there is a renewed interest in assessing to what extent the climate of the past has differed from that of today and what influence it has had upon man. Modern man has expanded his activities up to and beyond the limitations imposed by his environment. In the Third World, the pressures of increasing populations have forced people still dependent on primitive agricultural practices to occupy regions which have only a marginal capacity for food production. Industrialized societies continue to rely heavily upon technology to compensate for the harsh environment. Hybrid crops and livestock which are developed for high productivity in specific climatic conditions are more highly susceptible to unanticipated climatic conditions than the less productive native species. Global technology and economic strategies have spread through all parts of the world, forming an interdependent network which is increasing in its sensitivity to climatic variations. This sensitivity, coupled with the fact that extreme climatic fluctuations in one region may be linked by atmospheric circulation patterns to extreme climatic fluctuations in other regions, increases the likelihood of disruptions in trade, economics, and politics on a global scale.

Some Local Climate Trends in Four Cities of New York State

Abstract: From historical weather records, a preliminary assessment was made of local climate changes in four major urban areas of New York State. Particular emphasis was placed on cold season precipitation and possible relationships to man's activities. Total snowfall was found to have increased significantly from about 1940, the start of a period of sharp increases in urbanization and industrialization. The relationship was merely coincidental, with the underlying cause of snowfall increases due to natural causes, apparently in part to a corresponding decline in ambient temperature. A few climate trends appeared linked to anthropogenic causes, particularly in New York City.

On the Simulation of Climate and Climate Change with General Circulation Models.

Abstract: Increasing concern over possible anthropogenic impact on climate has led to an awareness that straightforward diagnostic procedures are necessary to measure climate and climate change in computer model experiments. Since the best documented (and most predictable) climate change is the extreme seasonal change from January to July, an obvious first application of any such set of procedures would be to determine if an atmospheric general circulation model (GCM) is capable of producing measurably different climates from a prescribed seasonal change in external forcing. Toward this end, objective statistical tests are applied to various measures of the climate to determine the extent to which sampled climate ensembles produced by January and July versions of a 5° horizontal resolution GCM developed several years ago at the National Center for Atmospheric Research differ. It is shown that while ensemble averages and standard deviations of globally averaged, time-averaged precipitation are not significa...

Local climates and growth climates of the sognefjord region

Abstract: In an agricultural appraisal of a particular region a climatic survey is of great importance. This especially applies to countries like Norway, where climate is marginal for several of the more valuable crops, and where rugged topography induces great contrasts in local climate over short distances. Sognefjord runs nearly due west to east from the Norwegian Sea to the central parts of southern Norway. The regional climate changes from a strongly oceanic type in the western parts to a marked continental type in the innermost parts, some 100 km from the open sea. Over this distance the average length of the growing season, td≥6°C, decreases from about 205 to about 165 days. A three-year survey of the region by means of a network of some 120 climatic stations revealed considerable changes over short distances in irridiation, temperature, precipitation and other climatic elements. The characteristics of the local growth climates are mainly determined by topography (aspect, exposure and height above sea level) and distance from the open sea and fjord. Local variations in warmth-growth climate, here expressed by the length of the growing season and the respiration equivalent, and variations in the water supply, expressed by potential precipitation deficit, are discussed. Practical applications in agricultural planning are considered.

The Impact of Climate on Political, Social, and Economic Change: A Comment

Abstract: The Impact of Climate on Political, Social, and Economic Change: A Comment That climate changes is well established. At issue is whether climate change has had any significant influence on the fluctuation of demographic variables or the level of economic activity, beyond its impact on those lands located at the margins of the temperate zone. According to Lamb and others, the preindustrial centuries of Europe, the period discussed in the papers of Andrew B. Appleby and Jan de Vries, were marked by low values of the long-term mean temperature in comparison with recent normals. This little ice age, stretching roughly from the last half of the sixteenth to the first half of the nineteenth century (with several warm interludes), was also characterized by enhanced variability of temperature from year to year and from decade to decade, particularly between 1550 and 1700. In some decades (the I570s, 1590s, and I620s), wet, cool summers constituted the most notable anomaly; in others (the i56os and i6oos), it was the severity of the winters; whereas in the i58os, 68os, and I69os, both summers and winters proved cold.1 Presumably, the relatively high number of anomalous decades reflects the enhanced climatic variability of the little ice age. At the same time the long-term negative temperature departures from recent normals seem modest, some i?C in global means. Although a change of this magnitude would produce significant ecological consequences on a secular time-scale, when we deal with human ecology attention must be given not only to population and the natural environment but also to technology, which has enabled human societies to buffer the influence of weather with notable success.

Climate Change Due to Anthropogenic Surface Albedo Modification

Abstract: Numerical experiments that dealt with the possible climatic impact of man-induced surface albedo change have primarily focused on individual regions (e.g. increased desert albedo, tropical deforestation, urbanization). Sagan et al. (1) suggest that the combination of anthropogenic albedo changes may have contributed to global climate changes in the past and may be continuing today. Using a statistical dynamic climate model with more realistic surface albedo changes than used in previous experiments, we have conducted a numerical experiment combining desertification of the Sahara and deforestation of the tropical rain forest. Over an area of 9 × 106 km2 at 20°N the desert albedo was increased from 0.16 to 0.35 and over 7 × 106 km2 at the equator and 10°S the rain forest albedo was increased from 0.07 to 0.16. While the most significant direct climatic responses were observed in the modified zones, high northern latitudes exhibited the greatest cooling through activation of the ice-albedo feedback process. In contrast to Sagan et al. (1), this experiment suggests that anthropogenic modification of surface albedo over the past few thousand years has had an impact on global climate which is likely quite small and probably undetectable.

Climatic Change and the Carbon Wealth of Nations

Abstract: A great deal of research is currently going into simulating the effects of increased atmospheric carbon dioxide on climate. This research considers the direct climatic effects of steadily rising atmospheric concentrations of carbon dioxide and usually assumes a rate of carbon dioxide increase from burning of fossil fuels which will lead to a doubling of airborne concentrations by some time in the first half of the twenty-first century. Such a rate is consistent with observations of carbon dioxide increases in the recent past, but it also depends crucially on implicit assumptions about the future functioning of the world economy. But, rather than make assumptions about the world economy, one can try to work backward from the carbon dioxide demanded for a mid-twenty-first century climatic change toward the physical carbon resources. Where in the earth will the carbon come from? How is it distributed with respect to present national and regional boundaries? Can this tell us something about the likelihood of realization of a CO2 problem? About the possibilities for its control? And, when combined with estimates of past contribution by geopolitical entities, does it tell us anything about responsibility for a CO2-induced climatic change?

Ein Hochdruckphasenübergang in Cordierit

Abstract: environment probably reflect small-scale oscillations in the rainfall and soil-moisture budget and/or changes in soil type [21]. Thus either during or just after the Arundian stage a climatic change occurred bringing in an essentially humid climatic regime, which continued into the Upper Carboniferous. A problem in recognizing such changes is to separate changes in palaeosol type caused by true climatic from those caused by local geomorphic changes. The absence of petrocalcic horizon bearing palaeosols above the Arundian as well as the occurrence of coal-bearing palaeosols and large-scale palaeokarstic surfaces indicates a significant change in climate. Also during the Arundian there was a fluctuation to a humid climate, lasting several thousand years followed by a lengthy period of aridity. A better idea of the complexity of Lower Carboniferous climates will only be achieved by further studies of palaeosol and palaeokarst distribution, but the Arundian seems to have been a period of significant climatic change, the implications of this for other aspects of geology, particularly palaeobotany are far reaching.

Impending climatic change and the fate of glaciers

Abstract: According to the data of glaciologists, a global warming of the climate may occur in the next 40–50 years. A change in the glaciation of mountains at temperate latitudes in Eurasia, on Arctic islands, in Greenland, and in East and West Antarctica is forecast on this basis. The article is published as a scientific discussion and the conclusions derived are not indisputable. [The paper may be read in conjunction with one by M. I. Budyko et al., “Impending climatic change,”; Soviet Geography September 1979, pp. 395–411.]

Future credible precipitation occurrences in Los Alamos, New Mexico

Abstract: I have studied many factors thought to have influenced past climatic change. Because they might recur, they are possible suspects for future climatic alterations. Most of these factors are totally unpredictable; therefore, they cast a shadow on the validity of derived climatic predictions. Changes in atmospheric conditions and in continental surfaces, variations in solar radiation, and in the earth's orbit around the sun are among the influential mechanisms investigated. Even when models are set up that include the above parameters, their reliability will depend on unpredictable variables totally alien to the model (like volcanic eruptions). Based on climatic records, however, maximum precipitation amounts have been calculated for different probability levels. These seem to correspond well to past precipitation occurrences, derived from tree ring indices. The link between tree ring indices and local climate has been established through regression analysis.

Botanical and Chemical Evidence of Climatic Change: A Comment

Abstract: strophic climatic events do play important and recognized roles, yet even in certain climatic catastrophes the effect is not the result of climate alone, but is in part a function of man's action as well. Two such events of recent memory are the droughts in the Sahel region of Africa and the Great Plains' "Dust Bowl" of the I930s. In both events man's activities intensified and worsened the climatic effects. In most cases, however, the climatic effects are modified or diffused to the point where they become difficult to identify with certainty. There are three reasons why the biological systems upon which climate is acting may not show direct and obvious responses, thus making the historical record difficult to interpret. One reason rests with the biological systems themselves, one is external to them, and one is a matter of scale. The resiliency that a biological system may exhibit toward a change in the climate can be remarkable. This ability to rebound following an imposed external stress is due to both physical and physiological characteristics of the system. A simple example is the rolling of maize leaves during periods of moisture stress, which serves to reduce leaf transpiration. External to the biological system are economic, political, and social structures that man has created. They often decrease our ability to detect the effects of climatic events. Commerce provides an excellent example of how the effect of even a climatic disaster in a region or country can be dissipated. Another example is the shifting by farmers from one crop to another in response to either climate or economics-which may be different faces of the same coin.

Meteorological consequences of natural or deliberate changes in the surface environment (with particular reference to the James Bay region)

Abstract: The Arctic and sub‐Arctic regions are suitable for model experimentation because surfaces covered by snow and ice change markedly from season to season. These regions lend themselves to studies of climatic change because changes in surface parameters significantly affect exchange processes for sensible and latent heat. A numerical model is used for the calculation of energy balance terms under a variety of surface conditions and for the change likely to be caused by the flooding of coniferous forest by a reservoir associated with the hydroelectric project in the James Bay region. The research was performed under contract for Atmospheric Environment Service Canada. From: Cahiers de Geographie de Quebec December 1974, pp. 445–461.

Modeling the prospects for climatic change: current state-of-the-art and implications

Abstract: It has been increasingly suggested that the world's climate is going to change in the next several decades, primarily as a result of anthropogenic perturbations to the global carbon cycle brought about by fossil fuel burning and large-scale deforestation. In order to cope with these future climatic changes, it is necessary that tools be developed to predict how complex systems respond to a given change of conditions. This report summarizes the status of our ability to model the planetary system that determines the climate. (ACR)