Showing papers on "Climate change published in 1971"

Climate Change in the North Pacific Using Ice-Rafted Detritus as a Climatic Indicator

Abstract: The variations in weight percent of the grain size fraction greater than 250 μ in nine cores from the North Pacific were determined using sampling intervals of 5 to 20 cm. Material in this size fraction is interpreted as transported by icebergs, and fluctuations are attributed to the waxing and waning of glaciers on the surrounding continents. At least eleven periods of increased ice rafting are detected in the cores during the time from 1.2 m.y. ago to the present, whereas only about four are identified from 1.2 m.y. to 2.5 m.y. B.P. The dating and time correlations are based on the magnetic stratigraphy, ash falls, and faunal extinctions. The ice-rafted detritus indicates a cooling beginning about 1.2 m.y. ago and becoming very intense between the Jaramillo event and the Brunhes-Matuyama boundary. This time may correspond to the initiation of mid-latitude glaciations of Europe and North America. At least six zones of ice-rafted sediment are present in the Brunhes normal polarity series. The correlations between these and the carbonate fluctuations of the central Pacific are good. Evidence for a marked interglacial ranging from about 460,000 to 530,000 yrs B.P. occurs within these cores. This interglacial may be worldwide in extent.

Variations in Magnetic Intensity and Climatic Changes

Abstract: CORRELATION between the variations of the Earth's magnetic field, fluctuations in atmospheric radiocarbon activity, and climatic changes during the past 7,000 yr has been discussed extensively in the past1–7. In addition, Harrison8 has suggested that reversals of the Earth's magnetic field could cause climatic changes. With an associate we have recently9 been able tentatively to conclude on the basis of studies of deep-sea sediment cores that in the past 470,000 yr the magnetism of the Earth has modulated climate. We have now extended the correlation between variations of the magnetic intensity and evidence of climatic change from deep-sea sediment cores back to 1.2 m.y.

Man's impact on the climate

Abstract: This is one of two volumes that provide more detailed scientific and technical information on global environmental problems than could adequately be summarized in the Report of the Study of Critical Environmental Problems (SCEP), "Man's Impact on the Global Environment " (MIT Press, 1970). SCEP presents the results of a one-month, interdisciplinary examination of the global climatic and ecological effects of man's activities which was sponsored by the Massachusetts Institute of Technology and conducted during the month of July 1970 at Williams College, Williamstown, Massachusetts.This and the companion volume, "Man's Impact on Terrestrial and Oceanic Ecosystems, " reproduce, supplement, and complement material found in the SCEP report and will serve as useful reference works for researchers and students in the many disciplines involved in solving the serious problems of environmental pollution.Theories and speculations about the effects of environmental pollution warn of both imminent and potential global catastrophes from--among other things--the build up of CO2 from fossil-fuel combustion, the accumulation of DDT in both animals and humans, and the systematic release of such toxic materials as heavy metals, oil, and radioactive substances. "Man's Impact on the Climate" provides a much-needed overview of the present state of knowledge about the climate, the atmospheric processes that produce climate and climate change and the interaction of pollutants with these processes; the modeling and monitoring tools that are available for learning more about these areas; and actions that might be taken to ameliorate problems that are understood.The book contains forty-eight chapters of varying length, scope, depth, complexity, and style--compiled from background materials prepared for SCEP, working papers written during the Study, and a few selected articles that have been previously published. SCEP Work Group reports that deal with climate and with atmospheric monitoring and the summary of those reports are reproduced in Part I. Part II provides a broad semitechnical view of the factors involved in determining climate and in changing climate and outlines the ways in which man might affect these processes by introducing pollutants into the environment.Mathematical modeling and monitoring techniques that are necessary to understand the factors influencing climate conditions are introduced in Parts III and IV, respectively. The next five sections discuss specific pollutants and their effects on the climate: Carbon Dioxide and Atmospheric Heating, Particles and Turbidity, Particles and Clouds, Contaminants of the Upper Atmosphere, and A Nonproblem and a Potential Problem (oxygen depletion and clearing of the Amazon forest). Each section treats the theoretical and empirical evidence available on predicted or observed effects and indicates the monitoring and measurement methods that can be used to increase knowledge in these areas and/or alert man to his impact on the climate. Monitoring techniques that are applicable to most of these problems are covered in detail in Part X."More research" is not the simple answer to environmental issues. A final section of the book illustrates some of the complex social, political, and technical issues that the scientists and his fellow citizens must confront together if decisions that could avert potential disasters are ever to be made and implemented.

Natural Resource Conservation: An Ecological Approach

Abstract: Natural resource conservation:an ecological approach , Natural resource conservation:an ecological approach , مرکز فناوری اطلاعات و اطلاع رسانی کشاورزی

Extended industrial revolution and climate change

Abstract: The earth's climate has changed noticeably within man's recorded history and much more dramatically during that longer period whose record we must examine in the geology of earth's crustal rock. To plan an intelligent use of our resources, we must frame our plans in a total environment; and the earth's climate is perhaps the determinant factor in this environment. We must understand how the climate is going to change and whether man's activities can influence climate. It is clear that if our activities are of sufficient scale to cause the climate to deteriorate, then they might also be made to improve it, at least for some minority of the earth's population. Understanding is also important on the part of those whose interest might be restraining such experiments.