Climatic change: a review of causes

1987 ◽  
Vol 17 (11) ◽  
pp. 1313-1339 ◽  
Author(s):  
J. B. Harrington
Keyword(s):  
Climatic Change ◽  
21St Century ◽  
Numerical Models ◽  
Continental Drift ◽  
Atmospheric Composition ◽  
Past Century ◽  
Aquatic Life ◽  
Radiant Intensity ◽  
The Past ◽  
The Impact

The earth's climate is constantly changing. Climatic change is effected by many factors: the influence of continental drift, variations in solar intensity, volcanism, the impact of meteors and comets, changes in the earth's orbital parameters, ice accumulation and depletion, variations in oceanic circulations and chemistry, changes in terrestrial and aquatic life, and changes in atmospheric composition and circulation. Despite these influences, many of them large, and despite changes in the sun's radiant intensity over the past 4.5 billion years, the average temperature of the earth's surface has remained remarkably constant, hovering near 15 °C. This implies the presence of strong negative feedbacks reacting to any major environmental change. During the past century, man's influence on his environment has been increasing at an unprecedented rate. Under this influence, and particularly because of the effect of the so-called "greenhouse gases," the global mean temperature is expected to rise approximately 2.5 °C by the middle of the 21st century. There remains a degree of uncertainty in this prediction because of unresolved problems in estimating various positive and negative feedback mechanisms in air, earth, ocean, ice, and vegetation interaction and in the unknown magnitude of volcanic activity. The finest numerical models and the fastest computers are, at present, inadequate to resolve all of the problems. However, the best scientific evidence points to a return by the middle of the 21st century to a climate similar to that of the climatic optimum 5000–6000 years ago. The degree of confidence in the direction, speed, and magnitude of the impending climatic change is sufficient that affected agencies should be actively mapping strategies to respond most advantageously to the expected changes. This is particularly true of forestry in Canada where climatic changes are expected to be large and the lifetime of current plantings will extend well into the period of anticipated change.

Civilization and Rapid Climatic Change

1988 ◽  
Vol 15 (1) ◽  
pp. 7-15 ◽  
Author(s):  
Reid A. Bryson
Keyword(s):  
Climatic Change ◽  
Volcanic Activity ◽  
Plate Tectonics ◽  
Field Experiments ◽  
Climatic Changes ◽  
Climatic Variation ◽  
Past Century ◽  
Ice Ages ◽  
The Past ◽  
The Impact

Research over the past century has shown that the rates and magnitudes of climatic change constitute a continuum. Changes have now been identified in the climatic record that range in duration from interannual through decades and centuries to the multi-millennial time-scale. Examples range from the drought years of the 1930 and 1970 decades to the ponderous comings and goings of the ice-ages. More recently it has become clear that some changes can be quite rapid. In recent decades great progress has been made in identifying the causes of climatic variation.The present understanding of the causes of climatic change emphasizes continental drift (or ‘plate tectonics’) at the million-years' scale, with pulses of plate movement producing significant bursts of volcanic activity that may act on the millennial or century scale. At the multi-millennial scale there is growing agreement that the variations in irradiance of the Earth, resulting from slow changes in the Sun-Earth geometry (the so-called Milankovitch variations), exercise the operative control on the timing of ice-ages and interglacials. At the decadal and interannual scales there is less agreement; but there is at least a body of research which suggests that significant volcanic activity is a contributing factor. There is considerable agreement—but little direct evidence—that anthropogenic causes such as increased carbon dioxide and other Man-made or-enhanced trace gases in the atmosphere, will be important in the coming decades.Cultural responses might be expected to differ across this continuum. To assess the expected response to a climatic variation, one must know at least the shape of the response surface.There is probably a critical threshold combination of climatic change magnitude and duration. Human cultures seem to be adapted to frequently-occurring short ‘aberrations’ from the expected climate. Some evidence indicates, on the other hand, that relatively small changes of climates (of the order of a century in duration) have been associated over the past 8,000 years with cultural changes that proved large enough to lead to different names being assigned in perhaps half of the cultural termini identified. A climate model which includes the effect of volcanic aerosols, suggests that most of the climatic changes associated with these globally synchronous cultural termini are related to peaks of volcanic activity. Some apparently catastrophic events have been recognized in this connection.There remains the problem of assessing, in realistic terms, the impact of large-magnitude climatic variations on modern human societies. Of particular concern is the effect of climatic events associated with very large-scale short-term insertions of aerosols into the atmosphere. It is likely that non-equilibrium models of the atmosphere, with specified sea-surface temperatures, would give realistic results if refined to the degree that they could replicate events of lesser magnitude which have occurred in the past century. At present there appear to be no models in which the formulation of the radiative effect of aerosols or gases gives a good match with observed radiative effects. It seems that much more research, including field experiments, will be needed if science is to supply reliable advice to society on the nature of coming climatic changes.

Law Librarianship and Legal Information Provision in the 21st Century

2008 ◽  
Vol 8 (1) ◽  
pp. 4-10 ◽  
Keyword(s):  
21St Century ◽  
Legal Education ◽  
Legal Profession ◽  
Information Provision ◽  
Key Factors ◽  
Legal Information ◽  
The Past ◽  
The World ◽  
The Future ◽  
The Impact

AbstractIn this analysis of the future of our profession, Barbara Tearle starts by looking at the past to see how much the world of legal information has evolved and changed. She considers the nature of the profession today and then identifies key factors which she believes will be of importance in the future, including the impact of globalisation; the potential changes to the legal profession; technology; developments in legal education; increasing commercialisation and changes to the law itself.

The Impact of New Technologies on Professional Development

2013 ◽  
pp. 40-52
Author(s):  
Sarah T. Meltzer
Keyword(s):  
Professional Development ◽  
Student Achievement ◽  
21St Century ◽  
New Technologies ◽  
Effective Professional Development ◽  
The Past ◽  
New Learning ◽  
Specific Activities ◽  
The Impact ◽  
Support Students

Professional development in schools is not a new concept; however, the impact of new technologies in the past two decades has shown it is important to incorporate research-based strategies in order to be effective. While strategies for curriculum-focused trainings may have been effective in the past, technology-focused training must take a different approach in the 21st century. Effective professional development will positively impact student achievement and is critical for sustainable school reform. This chapter addresses the importance of developing a new learning environment conducive to supporting professional development in technology. Key strategies necessary to support students’ needs in the 21st century are explained. Without an emphasis on specific activities and opportunities throughout the phases of planning and implementation, professional development will not be sustainable and student achievement will not be impacted.

The View from the Top: A Century of PS Presidents' Perspectives on the Paleontological Society and Paleontology

2008 ◽  
Vol 14 ◽  
pp. 1-15
Author(s):  
Patricia H. Kelley
Keyword(s):  
Continental Drift ◽  
Early Years ◽  
Second Century ◽  
Past Century ◽  
Science And Society ◽  
Mccarthy Era ◽  
The Past ◽  
Paleontological Society ◽  
Sister Organization ◽  
The 1960S

The Paleontological Society was founded in 1908, as a section of the Geological Society of America, for the purpose of promoting the science of paleontology. Although disciplinarily inclusive, our founders were an elitist, demographically limited group. Constitutional revisions over the past century trace the evolution of the PS, including increased democratization (with a setback during the McCarthy Era, but accelerating following the turmoil of society as a whole during the 1960s), internationalization, independence from the GSA and our sister organization SEPM, and broadening of our activities and concerns. Comments by Paleontological Society presidents, in their presidential addresses and/or a survey I conducted, reinforce these conclusions. In addition, the presidential addresses demonstrate the shifting concerns and interests of paleontologists over the past century: emphasis on stratigraphic paleontology during the early years of the Society; avoidance of the topic of evolution during the antievolution movement of the 1920s – 1950s; lack of participation in the debates over continental drift; development of paleobiology. Many presidents focused on the identity of paleontology, either praising our potential for contributions to science and society or bemoaning our status and recommending remedies for our situation. Despite some predictions of impending extinction of paleontology and the PS, both our Society and our field remain vigorous as we begin our second century.

scholarly journals Impact of Recent Climate Change on Water-Use Efficiency Strategies of Larix sibirica in the Altai-Sayan Mountain Range

Forests ◽  
2020 ◽  
Vol 11 (10) ◽  
pp. 1103
Author(s):  
Olga V. Churakova (Sidorova) ◽  
Marina V. Fonti ◽  
Rolf T. W. Siegwolf ◽  
Matthias Saurer ◽  
Vladimir S. Myglan
Keyword(s):  
Water Use ◽  
Air Temperature ◽  
Siberian Larch ◽  
Larix Sibirica ◽  
Strong Increase ◽  
Past Century ◽  
Mountain Range ◽  
The Past ◽  
Recent Climate ◽  
The Impact

A strong increase in the mean annual air temperature during the past 50 years by up to 0.54 °C was recorded in the Altai region (45°–52° N; 84°–99° E) compared to the global value of 0.07 °C over the period 1901–2008. The impact of the climatic changes on the hydrology are complex in these mountainous forest ecosystems and not fully understood. We aim to reveal differences in the intrinsic water-use efficiencies (iWUE) strategy by larch (Larix sibirica Ledeb.) derived from stable carbon isotopes at contrasting sites, ranging from the steppe (Ersin, Chadan) to high-elevation (Mongun, Koksu) sites of the Altai over the past century. The iWUE trends increased rapidly for all study sites except Chadan, where a decreasing trend after 2010 has been observed. This decline can be related to increased amount of precipitation compared to increased drought at the other sites. In general, the iWUE is increased up to 14% (1985–2019 compared to 1919–1984), which is lower compared to other studies across the globe likely due to harsh climatic conditions. Vapor pressure deficit and maximal air temperature are impacting Siberian larch significantly and affecting their iWUE differently at the high-elevated and steppe sites of the Altai over the past century.

The Impact of Anarchy on English Monasticism, 1135-1154

1974 ◽  
Vol 6 (3) ◽  
pp. 218-232 ◽  
Author(s):  
Thomas Callahan
Keyword(s):  
Civil Wars ◽  
Twelfth Century ◽  
Traditional View ◽  
Past Century ◽  
The Past ◽  
The Impact

King Stephen's reign has long been recognized as a crucial period for monasticism in England. Many authors have written about alleged anarchical conditions during those nineteen years, and scholars have done a great deal of work on twelfth century English monasticism; nevertheless, comparatively little attention has been paid to the impact of this supposed anarchy on the monastic establishment. This impact is the concern of this essay. Due to the limitation of space, I will confine myself to the material damages suffered by monastic houses during Stephen's reign and will offer an extended summary of my findings.The traditional picture of anarchy in England during Stephen's reign is that the civil wars wreaked havoc with nearly all aspects of life and inflicted massive and long lasting material damages. Medieval writers—most memorably the Peterborough chronicler— emotionally depicted scenes of terror and devastation, and the majority of later scholars—most notably H. W. C. Davis—upheld the basic validity of this picture. During the past century, however, historians have somewhat modified the traditional view. Whereas most medieval writers described an England embroiled in internal warfare for nearly all of Stephen's nineteen year reign, modern scholars have realized that the area of active fighting was more limited and that actual warfare lasted less than half of the reign. Also, modern scholars have shown that many of the occurrences in Stephen's reign were not characterized by aimless chaos and confusion, but rather by purposeful actions directed towards specific ends.

Death at the End of the 20th Century: Individual Processes and Developmental Tasks in Old Age

2002 ◽  
Vol 54 (4) ◽  
pp. 315-333 ◽  
Author(s):  
Christina Röcke ◽  
Katie E. Cherry
Keyword(s):  
Life Expectancy ◽  
Old Age ◽  
Personal Experience ◽  
Public Awareness ◽  
Developmental Tasks ◽  
Past Century ◽  
Research Practice ◽  
The Past ◽  
And Coping ◽  
The Impact

In this article, we address the topic of death from historic and contemporary perspectives. In the first section, we describe the changes in life expectancy, personal experience, and public awareness of death that have occurred over the past century. In the next section, we examine the impact these changes have had on the mastery of the two developmental tasks in adulthood, acceptance of one's own mortality and coping with the death of a spouse. We describe select findings from the literature on attitudes, fear or acceptance of death, and grief processes. Implications for research, practice, and social change are considered.

scholarly journals Compositional Spatio-Temporal PM2.5 Modelling in Wildfires

Atmosphere ◽  
2021 ◽  
Vol 12 (10) ◽  
pp. 1309
Author(s):  
Joseph Sánchez-Balseca ◽  
Agustí Pérez-Foguet
Keyword(s):  
Compositional Data ◽  
Numerical Models ◽  
Traditional Approach ◽  
Pearson Correlation ◽  
Atmospheric Composition ◽  
Quality Model ◽  
Potential Health ◽  
Compositional Approach ◽  
Spatio Temporal ◽  
The Impact

Wildfires are natural ecological processes that generate high levels of fine particulate matter (PM2.5) that are dispersed into the atmosphere. PM2.5 could be a potential health problem due to its size. Having adequate numerical models to predict the spatial and temporal distribution of PM2.5 helps to mitigate the impact on human health. The compositional data approach is widely used in the environmental sciences and concentration analyses (parts of a whole). This numerical approach in the modelling process avoids one common statistical problem: the spurious correlation. PM2.5 is a part of the atmospheric composition. In this way, this study developed an hourly spatio-temporal PM2.5 model based on the dynamic linear modelling framework (DLM) with a compositional approach. The results of the model are extended using a Gaussian–Mattern field. The modelling of PM2.5 using a compositional approach presented adequate quality model indices (NSE = 0.82, RMSE = 0.23, and a Pearson correlation coefficient of 0.91); however, the correlation range showed a slightly lower value than the conventional/traditional approach. The proposed method could be used in spatial prediction in places without monitoring stations.

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