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Minggu, 18 Mei 2014 | 0 komentar

Climate Change
(A Fundamental Analysis of the Greenhouse Effect)

Over recent years there has been considerable debate concerning the possibility of industrially induced increases in the concentration of carbon dioxide in the atmosphere giving rise to increased warming across the world. 

This Global Warming, often referred to in later times as “Climate Change”, has been accepted as a challenge by laymen, respected scientists, media moguls and politicians in a significant attempt to pursue the source of the problem and to prevent further damage being done to an increasingly fragile environment.  However, a large number of equally respected scientists and members of the public, appear to be less convinced of the need to take action and have put forward in some cases well and passionately argued reasons that the warming and other climatic changes observed since the industrial age are simply manifestations of many different natural cycles in global and regional climate.

Let there be no mistake, climate change is real, very real and of course has been for many millions of years.   The questions we now face is whether the large increases in recent years, in the concentration of atmospheric Carbon Dioxide, which is commensurate with the rate of increase in our burning of fossil fuels, is the main cause of the observed variations in climate and what will be the effect in the future.  Fortunately, in relation to this problem, there is an apparently unprecedented level of cooperation between the nations of the world, all of whom are keen to find the answers to these questions and to contribute significant resources, if necessary, towards reducing the impact of the predicted cataclysmic outcomes if we continue along the current path of developing energy sources based on these fuels.  A timely attempt has also been made by the United Nations to establish an effective working committee employing a large team of dedicated scientists to collate the evidence, from earlier literature, related to climatic effects of the presence of CO2 in the atmosphere and to establish accurate analytical models of the atmosphere based on this science, from which long range predictions might be made of the outcomes from increased levels of this otherwise benign and in fact life-giving gas.  While there appears to be a wide consensus in accepting the basic science used to create all of the very large number of these computer based models being used to quantify the problem, it is also reported that the outcomes from the models vary quite significantly and that the results given by them relating to various climatic parameters often show large differences between models, as indicated in Chapter 8 of the UN Intergovernmental Panel on Climate Change (IPCC) Report 2007.  The one exception to this uncertainty in the results appears to be that of changes in global temperatures for which the models consistently provide a well recognized increase in temperature of 1 to 4 oC over the next 50 to 100 years.  Further modeling appears to indicate that such increases in the average global temperature will not allow for a sustainable future for mankind on this planet as we know it, and that very dramatic and perhaps costly changes will need to be made to our energy production programmes in order to quell the flow of ever increasing calamitous events such as unprecedented melting of ice at the poles and the rising of sea levels in the tropics.  A worrying corollary to the apparent lack of consistency in the values obtained for many of the atmospheric parameters, is that this perhaps points to greater uncertainty in the temperature results than has yet been recognized and that the consistency with which they predict a positive change in temperature, while clearly showing that there will be a continuing increase, may in fact indicate a much larger increase than predicted. A matter of concern to many scientists seeking to understand this important issue, is the fact that the average global temperature appears not to have increased in the last ten years or may even have slightly decreased while CO2 levels have continued to rise.  Is this the lull before the storm?

Flowing quite naturally from these overwhelmingly pessimistic results obtained from very carefully designed computer based climate models, the world population is becoming increasingly anxious about facing an uncertain future and as a result, governments, quite rightly, are keen to provide the appropriate protection, by setting up committees of expert economists, scientists and engineers to advise, with a growing sense of urgency, on the necessary courses of action to quell the increasing anxieties of their constituents and to reduce as much as possible the burning of fossil fuels which are the main source of increased carbon emissions.
Climate change is one of the defining issues of our time. It is now more certain than ever, based on many lines of evidence, that humans are changing Earth’s climate. The atmosphere and oceans have warmed, accompanied by sea-level rise, a strong decline in Arctic sea ice, and other climate-related changes.
Greenhouse gases such as carbon dioxide (CO2) absorb heat (infrared radiation) emitted from Earth’s surface. Increases in the atmospheric concentrations of these gases cause Earth to warm by trapping more of this heat. Human activities - especially the burning of fossil fuels since the start of the Industrial Revolution - have increased atmospheric CO2concentrations by about 40%, with more than half the increase occurring since 1970. Since 1900, the global average surface temperature has increased by about 0.8 °C (1.4 °F). This has been accompanied by warming of the ocean, a rise in sea level, a strong decline in Arctic sea ice, and many other associated climate effects. Much of this warming has occurred in the last four decades. Detailed analyses have shown that the warming during this period is mainly a result of the increased concentrations of CO2 and other greenhouse gases. Continued emissions of these gases will cause further climate change, including substantial increases in global average surface temperature and important changes in regional climate. The magnitude and timing of these changes will depend on many factors, and slowdowns and accelerations in warming lasting a decade or more will continue to occur. However, long-term climate change over many decades will depend mainly on the total amount of CO2 and other greenhouse gases emitted as a result of human activities.
Project background
'Past climate -- future climate' Professor Eric Wolff
The Royal Society and the US National Academy of Sciences, with their similar missions to promote the use of science to benefit society and to inform critical policy debates, offer this new publication as a key reference document for decision makers, policy makers, educators, and other individuals seeking authoritative answers about the current state of climate change science. The publication makes clear what is well established, where consensus is growing, and where there is still uncertainty. It is written and reviewed by a UK-US team of leading climate scientists. It echoes and builds upon the long history of climate-related work from both national science academies, as well as the newest climate change assessment from the United Nations’ Intergovernmental Panel on Climate Change

The Green House Effect

As is very well known, the basis of the concerns over climate change is what has become known as “the green house effect”, even though it is almost as well known that the effect contains many elements which are not common to the gardener’s green house.  In the latter object, the main process which results in the warming of the interior is the removal of convection currents which are among the most significant means of cooling of the earth.  A secondary feature of the glass covering, is that its windows are approximately 90% transparent to the most intense parts of the solar spectrum, thus allowing the heat from the sun to enter almost unimpeded and to warm the surface of the leaves and the ground inside.  
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