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GREENHOUSE EFFECT

Sociologyindex, Sociology Books 2012, Sociology of Environment

Greenhouse Effect is a term from environmental science referring to an increase in the average temperature of the earth brought about by the effects of atmospheric pollution. Pollutants are suspended in the lower atmosphere above the earth and retard the loss of heat by convection from the earth's surface.

Environment activists have been highlighting the negative impact of Greenhouse Effect on the environment. The scientists and the politicians are now beginning to understand and estimate the calamitous effects of the Greenhouse Effect.

Greenhouse Effect is termed so because greenhouse is a transparent glass or plastic building for rearing or hastening the growth of plants.

Greenhouse effect is the heating of the surface and lower atmosphere of a planet due to the greater transparency of the atmosphere to visible radiation from the sun than to infrared radiation from the planet; greenhouse gas, carbon dioxide or another gas contributing to the greenhouse effect.

History of the greenhouse effect - M.D.H. Jones, A. Henderson-Sellers
The greenhouse effect is now commonly accepted by the scientific community, politicians and the general public. However, the misnomer 'greenhouse effect' has perpetuated, and there are a number of aspects of the effect which are poorly understood outside the atmospheric sciences. On such misconception is that greenhouse research is a recent phenomenon; another is that glasshouses are warmed by the same mechanism as lies at the heart of the greenhouse effect. This review traces the theory as far back as 1827, highlighting new directions and significant advances over that time. Four main themes can be discerned: 1) certain radiatively active gases are responsible for warming the planet ; 2) that humans can inadvertently influence this warming; 3) climate models are designed to permit prediction of the climatic changes in the atmospheric loadings of these gases but that they have not yet achieved this goal of prediction; and 4) many scenarios of changes, and especially of impact, are premised on relatively weak analysis. This latter point is illustrated by an examination of the relationship between increasing temperature and sea level change (the oceanic response to atmospheric warming). Current research suggests that sea-level rise is not likely to be as high as had previously been anticipated.

Evolution of Earth's Greenhouse Effect - Kiehl, J. T.
American Geophysical Union, Fall Meeting 2003, abstract #PP22B-01
The major factors contributing to Earth's greenhouse effect are discussed along with various quantitative methods for determining the greenhouse effect. Earth's greenhouse effect has evolved over geologic time scales and continues to evolve. The magnitude of Earth's greenhouse effect is explored for particular time periods of Earth's evolution from the Neoproterozoic to present. Coupled climate model simulations for these various time periods are used to estimate the magnitude of the greenhouse effect. A comparison is made between the present greenhouse effect and those of past times. The connection between the greenhouse effect and Earth's hydrologic cycle is also discussed. Finally, a comparison is made of between past greenhouse effects and that predicted for the end of the twenty-first century.

Greenhouse effect dependence on atmospheric concentrations of greenhouse substances and the nature of climate stability on Earth - V. G. Gorshkov and A. M. Makarieva
Petersburg Nuclear Physics Institute, 188300, Gatchina, St.-Petersburg, Russia
Abstract. Due to the exponential positive feedback between sea surface temperature and saturated water vapour concentration, dependence of the planetary greenhouse effect on atmospheric water content is critical for stability of a climate with extensive liquid hydrosphere.
In this paper on the basis of the law of energy conservation we develop a simple physically transparent approach to description of radiative transfer in an atmosphere containing greenhouse substances. It is shown that the analytical solution of the equation thus derived coincides with the exact solution of the well-known radiative transfer equation to the accuracy of 20% for all values of atmospheric optical depth. The derived equation makes it possible to easily take into account the non-radiative thermal fluxes (convection and latent heat) and obtain an analytical dependence of the greenhouse effect on atmospheric concentrations of a set of greenhouse substances with arbitrary absorption intervals.
The established dependence is used to analyse stability of the modern climate of Earth. It is shown that the modern value of global mean surface temperature, which corresponds to the liquid state of the terrestrial hydrosphere, is physically unstable. The observed stability of modern climate over geological timescales is therefore likely to be due to dynamic singularities in the physical temperature-dependent behaviour of the greenhouse effect. We hypothesise that such singularities may appear due to controlling functioning of the natural global biota and discuss major arguments in support of this conclusion.

Global Sea Level Rise and the Greenhouse Effect: Might They Be Connected?
W. R. PELTIER and A. M. TUSHINGHAM
Department of Physics, University of Toronto, Toronto, Ontario, Canada M5S 1A7.
Secular sea level trends extracted from tide gauge records of appropriately long duration demonstrate that global sea level may be rising at a rate in excess of 1 millimeter per year. However, because global coverage of the oceans by the tide gauge network is highly nonuniform and the tide gauge data reveal considerable spatial variability, there has been a well-founded reluctance to interpret the observed secular sea level rise as representing a signal of global scale that might be related to the greenhouse effect. When the tide gauge data are filtered so as to remove the contribution of ongoing glacial isostatic adjustment to the local sea level trend at each location, then the individual tide gauge records reveal sharply reduced geographic scatter and suggest that there is a globally coherent signal of strength 2.4 ± 0.90 millimeters per year that is active in the system. This signal could constitute an indication of global climate warming.

The Greenhouse Effect: Science and Policy
Stephen H. Schneider, National Center for Atmospheric Research
Global warming from the increase in greenhouse gases has become a major scientific and political issue during the past decade. That infrared radiation is trapped by greenhouse gases and particles in a planetary atmosphere and that the atmospheric CO2 level has increased by some 25 percent since 1850 because of fossil fuel combustion and land use (largely deforestation) are not controversial; levels of other trace greenhouse gases such as methane and chlorofluorocarbons have increased by even larger factors. Estimates of present and future effects, however, have significant uncertainties. There have also recently been controversial claims that a global warming signal has been detected. Results from most recent climatic models suggest that global average surface temperatures will increase by some 2° to 6°C during the next century, but future changes in greenhouse gas concentrations and feedback processes not properly accounted for in the models could produce greater or smaller increases. Sea level rises of 0.5 to 1.5 meters are typically projected for the next century, but there is a small probability of greater or even negative change. Forecasts of the distribution of variables such as soil moisture or precipitation patterns have even greater uncertainties. Policy responses range from engineering countermeasures to passive adaptation to prevention and a "law of the atmosphere." One approach is to implement those policies now that will reduce emissions of greenhouse gases and have additional societal benefits. Whether the uncertainties are large enough to suggest delaying policy responses is not a scientific question per se, but a value judgment.

The greenhouse effect and climate change - F W Taylor, Dept. of Phys., Oxford Univ., UK
Abstract. On any planet with an atmosphere, the surface is warmed not only by the Sun directly but also by downward-propagating infrared radiation emitted by the atmosphere. On the Earth, this phenomenon, known as the greenhouse effect, keeps the mean surface temperature some 33 K warmer than it would otherwise be and is therefore essential to life. The radiative processes which are responsible for the greenhouse effect involve mainly minor atmospheric constituents, the amounts of which can change either naturally or as a by-product of human activities. The growth of the latter is definitely tending to force a general global surface warming, although because of problems in modelling complicated feedback processes, for example those involving water vapour, ozone, clouds, and the oceans, the precise rates of change and the local patterns which should be expected are not yet very well known. The author reviews the physical processes involved in the greenhouse effect and discusses current progress, theoretical and experimental, towards an understanding of the effect on the climate, especially the mean surface temperature, of recent and expected changes in atmospheric composition. It also provides an overview of recent expert forecasts of climatic changes in the next few decades, and discusses their limitations.

Experimental short film about greenhouse effect: EFECTO INVERNADERO (greenhouse effect) by Andres Victorero - vimeo.com

Geological Assessment of the Greenhouse Effect
Thomas J. Crowley, Department of Oceanography, Texas A&M University, College Station, Texas.
ABSTRACT: Geologic studies provide a valuable perspective on the importance of greenhouse forcing for climate change. On both Pleistocene and tectonic time scales, changes in climate are positively correlated with greenhouse gas variations. However, the sensitivity of the system to greenhouse gas changes cannot yet be constrained by paleoclimate data below its present large range. Geologic records do not support one of the major predictions of greenhouse models—namely, that tropical sea surface temperatures will increase. Geologic data also suggest that winter cooling in high-latitude land areas is less than predicted by models. As the above-mentioned predictions appear to be systemic features of the present generation of climate models, some significant changes in model design may be required to reconcile models and geologic data. However, full acceptance of this conclusion requires more measurements and more systematic compilations of existing geologic data. Since progress in data collection in this area has been quite slow, uncertainties associated with these conclusions may persist for some time.

Knowledge about the Greenhouse Effect and the Effects of the Ozone Layer among Norwegian Pupils Finishing Compulsory Education in 1989, 1993, and 2005—What Now?
P. J. Kirkeby Hansen, Oslo University College, Norway
Abstract: The greenhouse effect and the effects of the ozone layer have been in the media and public focus for more than two decades. During the same period, Norwegian compulsory schools have had four national curricula. The two last-mentioned prescribe explicitly the two topics. Media and public discourse might have been sources of information causing informal learning among pupils. The point of departure for this questionnaire-based examination of the development of pupils' knowledge about the greenhouse effect and the effects of the ozone layer from 1989 to 2005 is the changing curricula and formal and informal learning. In 2005 the trends seem to be that more pupils confuse the greenhouse effect with the effects of the ozone layer. At the same time, specific knowledge about the greenhouse effect is improving. This article will discuss some possible causes for these trends, and give some recommendations for teaching the topics in accordance with the last national curriculum implemented in 2006.

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