Global WarmingI INTRODUCTIONGlobal Warming, increase in the average temperature of the atmosphere, oceans, and landmasses ofEarth. The planet has warmed (and cooled) many times during the 4.65 billion years of its history. Atpresent Earth appears to be facing a rapid warming, which most scientists believe results, at least in part, from human activities. The chief cause of this warming is thought to be the burning of fossil fuels, such as coal, oil, and natural gas, which releases into the atmosphere carbon dioxide and other substances known as greenhouse gases. As the atmosphere becomes richer in these gases, it becomes a better insulator, retaining more of the heat provided to the planet by the Sun. The average surface temperature of Earth is about 15°C (59°F). Over the last century, this average has risen by about 0.6 Celsius degree (1 Fahrenheit degree). Scientists predict further warming of 1.4 to 5.8 Celsius degrees (2.5 to 10.4 Fahrenheit degrees) by the year 2100. This temperature rise is expected to melt polar ice caps and glaciers as well as warm the oceans, all of which will expand ocean volume and raise sea level by an estimated 9 to 100 cm (4 to 40 in), flooding some coastal regions and even entire islands. Some regions in warmer climates will receive more rainfall than before, but soils will dry out faster between storms. This soil desiccation may damage food crops, disrupting food supplies in some parts of the world. Plant and animal species will shift their ranges toward the poles or to higher elevations seeking cooler temperatures, and species that cannot do so may become extinct. The potential consequences of global warming are so great that many of the world's leading scientists have called for international cooperation and immediate action to counteract the problem.II THE GREENHOUSE EFFECTThe energy that lights and warms Earth comes from the Sun. Most of the energy that floods onto our planet is short-wave radiation, including visible light. When this energy strikes the surface of Earth, the energy changes from light to heat and warms Earth. Earth’s surface, in turn, releases some of this heat as long-wave infrared radiation. Much of this long-wave infrared radiation makes it all the way back out to space, but a portion remains trapped in Earth’s atmosphere. Certain gases in the atmosphere, including water vapor, carbon dioxide, and methane, provide the trap. Absorbing and reflecting infrared waves radiated by Earth, these gases conserve heat as the glass in a greenhouse does and are thus known as greenhouse gases. As the concentration of these greenhouse gases in the atmosphere increases, more heat energy remains trapped below. All life on Earth relies on this greenhouse effect—without it, the planet would be colder by about 33 Celsius degrees (59 Fahrenheit degrees), and ice would cover Earth from pole to pole. However, a growing excess of greenhouse gases in Earth’s atmosphere threatens to tip the balance in the other direction—toward continual warming.III TYPES OF GREENHOUSE GASESGreenhouse gases occur naturally in the environment and also result from human activities. By far the most abundant greenhouse gas is water vapor, which reaches the atmosphere through evaporation from oceans, lakes, and rivers.Carbon dioxide is the next most abundant greenhouse gas. It flows into the atmosphere from many natural processes, such as volcanic eruptions; the respiration of animals, which breathe in oxygen and exhale carbon dioxide; and the burning or decay of organic matter, such as plants. Carbon dioxide leaves the atmosphere when it is absorbed into ocean water and through the photosynthesis of plants, especially trees. Photosynthesis breaks up carbon dioxide, releasing oxygen into the atmosphere and incorporating the carbon into new plant tissue.Humans escalate the amount of carbon dioxide released to the atmosphere when they burn fossil fuels, solid wastes, and wood and wood products to heat buildings, drive vehicles, and generate electricity. At the same time, the number of trees available to absorb carbon dioxide through photosynthesis has been greatly reduced by deforestation, the long-term destruction of forests by indiscriminate cutting of trees for lumber or to clear land for agricultural activities.Ultimately, the oceans and other natural processes absorb excess carbon dioxide in the atmosphere.However, human activities have caused carbon dioxide to be released to the atmosphere at rates much faster than that at which Earth’s natural processes can cycle this gas. In 1750 there were about 281 molecules of carbon dioxide per million molecules of air (abbreviated as parts per million, or ppm). Today atmospheric carbon dioxide concentrations are 368 ppm, which reflects a 31 percent increase.Atmospheric carbon dioxide concentration increases by about 1.5 ppm per year. If current predictions prove accurate, by the year 2100 carbon dioxide will reach concentrations of more than 540 to 970 ppm.At the highest estimation, this concentration would be triple the levels prior to the Industrial Revolution, the widespread replacement of human labor by machines that began in Britain in the mid-18th century and soon spread to other parts of Europe and to the United States.

Methane is an even more effective insulator, trapping over 20 times more heat than does the same amount of carbon dioxide. Methane is emitted during the production and transport of coal, natural gas, and oil. Methane also comes from rotting organic waste in landfills, and it is released from certain animals, especially cows, as a byproduct of digestion. Since the beginning of the Industrial Revolution in the mid- 1700s, the amount of methane in the atmosphere has more than doubled.Nitrous oxide is a powerful insulating gas released primarily by burning fossil fuels and by plowing farm soils. Nitrous oxide traps about 300 times more heat than does the same amount of carbon dioxide. The concentration of nitrous oxide in the atmosphere has increased 17 percent over preindustrial levels. In addition, greenhouse gases are produced in many manufacturing processes. Perfluorinated compounds result from the smelting of aluminum. Hydrofluorocarbons form during the manufacture of many products, including the foams used in insulation, furniture, and car seats. Refrigerators built in some developing nations still use chlorofluorocarbons as coolants. In addition to their ability to retain atmospheric heat, some of these synthetic chemicals also destroy Earth’s high-altitude ozone layer, the protective layer of gases that shields Earth from damaging ultraviolet radiation. For most of the 20th century these chemicals have been accumulating in the atmosphere at unprecedented rates. But since 1995, in response to regulations enforced by the Montréal Protocol on Substances that Deplete the Ozone Layer and its amendments, the atmospheric concentrations of many of these gases are either increasing more slowly or decreasing. Scientists are growing concerned about other gases produced from manufacturing processes that pose an environmental risk. In 2000 scientists identified a substantial rise in atmospheric concentrations of a newly identified synthetic compound called trifluoromethyl sulfur pentafluoride. Atmospheric concentrations of this gas are rising quickly, and although it still is extremely rare in the atmosphere, scientists are concerned because the gas traps heat more effectively than all other known greenhouse gases. Perhaps more worrisome, scientists have been unable to confirm the industrial source of the gas.IV MEASURING GLOBAL WARMINGAs early as 1896 scientists suggested that burning fossil fuels might change the composition of the atmosphere and that an increase in global average temperature might result. The first part of this hypothesis was confirmed in 1957, when researchers working in the global research program called theInternational Geophysical Year sampled the atmosphere from the top of the Hawaiian volcano Mauna Loa. Their instruments indicated that carbon dioxide concentration was indeed rising. Since then, the composition of the atmosphere has been carefully tracked. The data collected show undeniably that the concentrations of greenhouse gases in the atmosphere are increasing. Scientists have long suspected that the global climate, the long-term average pattern of temperature, was also growing warmer, but they were unable to provide conclusive proof. Temperatures vary widely all the time and from place to place. It takes many years of climate observations to establish a trend. Records going back to the late 1800s did seem to show a warming trend, but these statistics were spotty and untrustworthy. Early weather stations often were located near cities, where temperature measurements were affected by the heat emitted from buildings and vehicles and stored by building materials and pavements. Since 1957, however, data have been gathered from more reliable weather stations, located far away from cities, and from satellites. These data have provided new, more accurate measurements, especially for the 70 percent of the planetary surface that is ocean water (see Satellite, Artificial). These more accurate records indicate that a surface warming trend exists and that, moreover, it has become more pronounced. Looking back from the end of the 20th century, records show that the ten warmest years of the century all occurred after 1980, and the three hottest years occurred after 1990, with 1998 being the warmest year of all. Greenhouse gas concentrations are increasing. Temperatures are rising. But does the gas increase necessarily cause the warming, and will these two phenomena continue to occur together? In 1988 the United Nations Environment Program and the World Meteorological Organization established a panel of 200 leading scientists to consider the evidence. In its Third Assessment Report, released in 2001, this Intergovernmental Panel on Climate Change (IPCC) concluded that global air temperature had increased 0.6 Celsius degree (1 Fahrenheit degree) since 1861. The panel agreed that the warming was caused primarily by human activities that add greenhouse gases to the atmosphere. The IPCC predicted in 2001 that the average global temperature would rise by another 1.4 to 5.8 Celsius degrees (2.5 to 10.4 Fahrenheit degrees) by the year 2100.The IPCC panel cautioned that even if greenhouse gas concentrations in the atmosphere ceased growing by the year 2100, the climate would continue to warm for a period after that as a result of past emissions. Carbon dioxide remains in the atmosphere for a century or more before nature can dispose of it. If greenhouse gas emissions continue to increase, experts predict that carbon dioxide concentrations in the atmosphere could rise to more than three times preindustrial levels early in the 22nd century, resulting in dramatic climate changes. Large climate changes of the type predicted are not unprecedented; indeed, they have occurred many times in the history of Earth. However, human beings would face this latest climate swing with a huge population at risk.

V EFFECTS OF GLOBAL WARMINGScientists use elaborate computer models of temperature, precipitation patterns, and atmosphere circulation to study global warming. Based on these models, scientists have made several predictions about how global warming will affect weather, sea levels, coastlines, agriculture, wildlife, and human health.A WeatherScientists predict that during global warming, the northern regions of the Northern Hemisphere will heat up more than other areas of the planet, northern and mountain glaciers will shrink, and less ice will float on northern oceans. Regions that now experience light winter snows may receive no snow at all. In temperate mountains, snowlines will be higher and snowpacks will melt earlier. Growing seasons will be longer in some areas. Winter and nighttime temperatures will tend to rise more than summer and daytime ones. The warmed world will be generally more humid as a result of more water evaporating from the oceans. Scientists are not sure whether a more humid atmosphere will encourage or discourage further warming. On the one hand, water vapor is a greenhouse gas, and its increased presence should add to the insulating effect. On the other hand, more vapor in the atmosphere will produce more clouds, which reflect sunlight back into space, which should slow the warming process. Greater humidity will increase rainfall, on average, about 1 percent for each Fahrenheit degree of warming. (Rainfall over the continents has already increased by about 1 percent in the last 100 years.) Storms are expected to be more frequent and more intense. However, water will also evaporate more rapidly from soil, causing it to dry out faster between rains. Some regions might actually become drier than before. Winds will blow harder and perhaps in different patterns. Hurricanes, which gain their force from the evaporation of water, are likely to be more severe. Against the background of warming, some very cold periods will still occur. Weather patterns are expected to be less predictable and more extreme.B Sea LevelsAs the atmosphere warms, the surface layer of the ocean warms as well, expanding in volume and thus raising sea level. Warming will also melt much glacier ice, especially around Greenland, further swelling the sea. Sea levels worldwide rose 10 to 25 cm (4 to 10 in) during the 20th century, and IPCC scientists predict a further rise of 9 to 88 cm (4 to 35 in) in the 21st century. Sea-level changes will complicate life in many coastal regions. A 100-cm (40-in) rise could submerge 6 percent of The Netherlands, 17.5 percent of Bangladesh, and most or all of many islands. Erosion of cliffs, beaches, and dunes will increase. Storm surges, in which winds locally pile up water and raise the sea, will become more frequent and damaging. As the sea invades the mouths of rivers, flooding from runoff will also increase upstream. Wealthier countries will spend huge amounts of money to protect their shorelines, while poor countries may simply evacuate low-lying coastal regions. Even a modest rise in sea level will greatly change coastal ecosystems. A 50-cm (20-in) rise will submerge about half of the present coastal wetlands of the United States. New marshes will form in many places, but not where urban areas and developed landscapes block the way. This sea-level rise will cover much of the Florida Everglades.C AgricultureA warmed globe will probably produce as much food as before, but not necessarily in the same places.Southern Canada, for example, may benefit from more rainfall and a longer growing season. At the same time, the semiarid tropical farmlands in some parts of Africa may become further impoverished. Desert farm regions that bring in irrigation water from distant mountains may suffer if the winter snowpack, which functions as a natural reservoir, melts before the peak growing months. Crops and woodlands may also be afflicted by more insects and plant diseases.D Animals and PlantsAnimals and plants will find it difficult to escape from or adjust to the effects of warming because humans occupy so much land. Under global warming, animals will tend to migrate toward the poles and up mountainsides toward higher elevations, and plants will shift their ranges, seeking new areas as old habitats grow too warm. In many places, however, human development will prevent this shift. Species that find cities or farmlands blocking their way north or south may die out. Some types of forests, unable to propagate toward the poles fast enough, may disappear.E Human HealthIn a warmer world, scientists predict that more people will get sick or die from heat stress, due less to hotter days than to warmer nights (giving the sufferers less relief). Diseases now found in the tropics, transmitted by mosquitoes and other animal hosts, will widen their range as these animal hosts move into regions formerly too cold for them. Today 45 percent of the world’s people live where they might get bitten by a mosquito carrying the parasite that causes malaria; that percentage may increase to 60 percent if temperatures rise. Other tropical diseases may spread similarly, including dengue fever, yellow fever, and encephalitis. Scientists also predict rising incidence of allergies and respiratory diseases as warmer air grows more charged with pollutants, mold spores, and pollens.VI DEBATES OVER GLOBAL WARMING

Scientists do not all agreed about the nature and impact of global warming. A few observers still question whether temperatures have actually been rising at all. Others acknowledge past change but argue that it is much too early to be making predictions for the future. Such critics may also deny that the evidence for the human contribution to warming is conclusive, arguing that a purely natural cycle may be driving temperatures upward. The same dissenters tend to emphasize the fact that continued warming could have benefits in some regions. Scientists who question the global warming trend point to three puzzling differences between the predictions of the global warming models and the actual behavior of the climate. First, the warming trend stopped for three decades in the middle of the 20th century; there was even some cooling before the climb resumed in the 1970s. Second, the total amount of warming during the 20th century was only about half what computer models predicted. Third, the troposphere, the lower region of the atmosphere, did not warm as fast as the models forecast. However, global warming proponents believe that two of the three discrepancies have now been explained.The lack of warming at midcentury is now attributed largely to air pollution that spews particulate matter, especially sulfates, into the upper atmosphere. These particulates, also known as aerosols, reflect some incoming sunlight out into space. Continued warming has now overcome this effect, in part because pollution control efforts have made the air cleaner. The unexpectedly small amount of total warming since 1900 is now attributed to the oceans absorbing vast amounts of the extra heat. Scientists long suspected that this was happening but lacked the data to prove it. In 2000 the U.S. National Oceanic and Atmospheric Administration (NOAA) offered a new analysis of water temperature readings made by observers around the world over 50 years. Records showed a distinct warming trend: World ocean temperatures in 1998 were higher than the 50-year average by 0.2 Celsius degree (0.3 Fahrenheit degree), a small but very significant amount. The third discrepancy is the most puzzling. Satellites detect less warming in the troposphere than the computer models of global climate predict. According to some critics, the atmospheric readings are right, and the higher temperatures recorded at Earth’s surface are not to be trusted. In January 2000 a panel appointed by the National Academy of Sciences to weigh this argument reaffirmed that surface warming could not be doubted. However, the lower-than-predicted troposphere measurements have not been entirely explained.VII EFFORTS TO CONTROL GLOBAL WARMINGThe total consumption of fossil fuels is increasing by about 1 percent per year. No steps currently being taken or under serious discussion will likely prevent global warming in the near future. The challenge today is managing the probable effects while taking steps to prevent detrimental climate changes in the future. Damage can be curbed locally in various ways. Coastlines can be armored with dikes and barriers to block encroachments of the sea. Alternatively, governments can assist coastal populations in moving to higher ground. Some countries, such as the United States, still have the chance to help plant and animal species survive by preserving habitat corridors, strips of relatively undeveloped land running north and south. Species can gradually shift their ranges along these corridors, moving toward cooler habitats. There are two major approaches to slowing the buildup of greenhouse gases. The first is to keep carbon dioxide out of the atmosphere by storing the gas or its carbon component somewhere else, a strategy called carbon sequestration. The second major approach is to reduce the production of greenhouse gases.A Carbon SequestrationThe simplest way to sequester carbon is to preserve trees and to plant more. Trees, especially young and fast-growing ones, soak up a great deal of carbon dioxide, break it down in photosynthesis, and store the carbon in new wood. Worldwide, forests are being cut down at an alarming rate, particularly in the tropics. In many areas, there is little regrowth as land loses fertility or is changed to other uses, such as farming or building housing developments. Reforestation could offset these losses and counter part of the greenhouse buildup. Many companies and governments in the United States, Norway, Brazil, Malaysia, Russia, and Australia have initiated reforestation projects. In Guatemala, the AES Corporation, a U.S.-based electrical company, has joined forces with the World Resources Institute and the relief agency CARE to create community woodlots and to teach local residents about tree-farming practices. The trees planted are expected to absorb up to 58 million tons of carbon dioxide over 40 years. Carbon dioxide gas can also be sequestered directly. Carbon dioxide has traditionally been injected into oil wells to force more petroleum out of the ground or seafloor. Now it is being injected simply to isolate it underground in oil fields, coal beds, or aquifers. At one natural gas drilling platform off the coast of Norway, carbon dioxide brought to the surface with the natural gas is captured and reinjected into an aquifer from which it cannot escape. The same process can be used to store carbon dioxide released by a power plant, factory, or any large stationary source. Deep ocean waters could also absorb a great deal of carbon dioxide. The feasibility and environmental effects of both these options are now under study by international teams. In an encouraging trend, energy use around the world has slowly shifted away from fuels that release a great deal of carbon dioxide toward fuels that release somewhat less of this heat-trapping gas. Wood was the first major source of energy used by humans. With the dawn of the Industrial Revolution in the 18th century, coal became the dominant energy

source. By the mid-19th century oil had replaced coal in dominance, fueling the internal combustion engines that were eventually used in automobiles. By the 20th century, natural gas began to be used worldwide for heating and lighting. In this progression, combustion of natural gas releases less carbon dioxide than oil, which in turn releases less of the gas than do either coal or wood. Nuclear energy, though controversial for reasons of safety and the high costs of nuclear waste disposal, releases no carbon dioxide at all. Solar power, wind power, and hydrogen fuel cells also emit no greenhouse gases. Someday these alternative energy sources may prove to be practical, low-pollution energy sources, although progress today is slow.B National and Local ProgramsThe developed countries are all working to reduce greenhouse emissions. Several European countries impose heavy taxes on energy usage, designed partly to curb such emissions. Norway taxes industries according to the amount of carbon dioxide they emit. In The Netherlands, government and industry have negotiated agreements aimed at increasing energy efficiency, promoting alternative energy sources, and cutting down greenhouse gas output. In the United States, the Department of Energy, the Environmental Protection Agency, product manufacturers, local utilities, and retailers have collaborated to implement the Energy Star program. This voluntary program rates appliances for energy use and gives some money back to consumers who buy efficient machines. The Canadian government has established the FleetWise program to cut carbon dioxide emissions from federal vehicles by reducing the number of vehicles it owns and by training drivers to use them more efficiently. By 2004, 75 percent of Canadian federal vehicles are to run on alternative fuels, such as methanol and ethanol. Many local governments are also working against greenhouse emissions by conserving energy in buildings, modernizing their vehicles, and advising the public. Individuals, too, can take steps. The same choices that reduce other kinds of pollution work against global warming. Every time a consumer buys an energy efficient appliance; adds insulation to a house; recycles paper, metal, and glass; chooses to live near work; or commutes by public transportation, he or she is fighting global warming.C International AgreementsInternational cooperation is required for the successful reduction of greenhouse gases. In 1992 at the Earth Summit in Rio de Janeiro, Brazil, 150 countries pledged to confront the problem of greenhouse gases and agreed to meet again to translate these good intentions into a binding treaty. In 1997 in Japan, 160 nations drafted a much stronger agreement known as the Kyōto Protocol. This treaty, which has not yet been implemented, calls for the 38 industrialized countries that now release the most greenhouse gases to cut their emissions to levels 5 percent below those of 1990. This reduction is to be achieved no later than 2012. Initially, the United States voluntarily accepted a more ambitious target, promising to reduce emissions to 7 percent below 1990 levels; the European Union, which had wanted a much tougher treaty, committed to 8 percent; and Japan, to 6 percent. The remaining 122 nations, mostly developing nations, were not asked to commit to a reduction in gas emissions. But in 2001 newly elected U.S. president George W. Bush renounced the treaty saying that such carbon dioxide reductions in the United States would be too costly. He also objected that developing nations would not be bound by similar carbon dioxide reducing obligations. The Kyōto Protocol could not go into effect unless industrial nations accounting for 55 percent of 1990 greenhouse gas emissions ratified it. That requirement was met in 2004 when the cabinet of Russian president Vladimir Putin approved the treaty, paving the way for it to go into effect in 2005.Some critics find the Kyōto Protocol too weak. Even if it were enforced immediately, it would only slightly slow the buildup of greenhouse gases in the atmosphere. Much stronger action would be required later, particularly because the developing nations exempted from the Kyōto rules are expected to produce half the world’s greenhouse gases by 2035. The most influential opponents of the protocol, however, find it too strong. Opposition to the treaty in the United States is spurred by the oil industry, the coal industry, and other enterprises that manufacture or depend on fossil fuels. These opponents claim that the economic costs to carry out the Kyōto Protocol could be as much as $300 billion, due mainly to higher energy prices. Proponents of the Kyōto sanctions believe the costs will prove more modest—$88 billion or less—much of which will be recovered as Americans save money after switching to more efficient appliances, vehicles, and industrial processes. Behind the issue of cost lies a larger question: Can an economy grow without increasing its greenhouse gas emissions at the same time? In the past, prosperity and pollution have tended to go together. Can they now be separated, or decoupled, as economists say? In nations with strong environmental policies, economies have continued to grow even as many types of pollution have been reduced. However, limiting the emission of carbon dioxide has proved especially difficult. For example, The Netherlands, a heavily industrialized country that is also an environmental leader, has done very well against most kinds of pollution but has failed to meet its goal of reducing carbon dioxide output. After 1997 representatives to the Kyōto Protocol met regularly to negotiate a consensus about certain unresolved issues , such as the rules, methods, and penalties that should be enforced in each country to slow greenhouse emissions. The negotiators designed a system in which nations with successful cleanup programs could profit by selling unused pollution rights to other nations. For example, nations

that find further improvement difficult, such as The Netherlands, could buy pollution credits on the market, or perhaps earn them by helping reduce greenhouse gas emissions in less developed countries, where more can be achieved at less expense. Russia, in particular, stood to benefit from this system. In 1990 the Russian economy was in a shambles, and its greenhouse gas emissions were huge. Since then Russia has already cut its emissions by more than 5 percent below 1990 levels and is in a position to sell emission credits to other industrialized countries, particularly those in the European Union (EU).Contributed By:John HartMicrosoft ® Encarta ® Reference Library 2005. © 1993-2004 Microsoft Corporation. All rights reserved.Disadvantages of Global Warming

Ocean circulation disrupted, disrupting and having unknown effects on world climate.

Higher sea level leading to flooding of low-lying lands and deaths and disease from flood and evacuation.

Deserts get drier leaving to increased desertification. Changes to agricultural production that can lead to food

shortages. Water shortages in already water-scarce areas. Starvation, malnutrition, and increased deaths due to food and

crop shortages. More extreme weather and an increased frequency of severe

and catastrophic storms. Increased disease in humans and animals. Increased deaths from heat waves. Extinction of additional species of animals and plants. Loss of animal and plant habitats. Increased emigration of those from poorer or low-lying

countries to wealthier or higher countries seeking better (or non-deadly) conditions.

Additional use of energy resources for cooling needs. Increased air pollution. Increased allergy and asthma rates due to earlier blooming of

plants. Melt of permafrost leads to destruction of structures,

landslides, and avalanches. Permanent loss of glaciers and ice sheets. Cultural or heritage sites destroyed faster due to increased

extremes. Increased acidity of rainfall. Earlier drying of forests leading to increased forest fires in size

and intensity. Increased cost of insurance as insurers pay out more claims

resulting from increasingly large disasters.Advantages of Global Warming

Arctic, Antarctic, Siberia, and other frozen regions of earth may experience more plant growth and milder climates.

The next ice age may be prevented from occurring. Northwest Passage through Canada's formerly-icy north opens

up to sea transportation. Less need for energy consumption to warm cold places. Fewer deaths or injuries due to cold weather. Longer growing seasons could mean increased agricultural

production in some local areas. Mountains increase in height due to melting glaciers, becoming

higher as they rebound against the missing weight of the ice. II Global Warming in the Past

Earth has warmed and cooled many times since its formation about 4.6 billion years ago. Global climate changes were due to many factors, including massive volcanic eruptions, which increased carbon dioxide in the atmosphere; changes in the intensity of energy emitted by the Sun; and variations in Earth’s position relative to the Sun, both in its orbit and in the inclination of its spin axis. Variations in Earth’s position, known as Milankovitch cycles, combine to produce cyclical changes in the global climate. These cycles are believed to be responsible for the repeated advance and retreat of glaciers and ice sheets during the Pleistocene Epoch (1.8 million to 11,500 years before present), when Earth went through fairly regular cycles of colder “glacial” periods (also known as ice ages) and warmer “interglacial” periods. Glacial periods occurred at roughly 100,000-year intervals. An interglacial period began about 10,000 years ago, when the last ice age came to an end. Prior to that ice age, an interglacial period occurred about 125,000 years ago. During interglacial periods, greenhouse gases such as carbon dioxide and methane naturally increase in the atmosphere from increased plant and animal

life. But since 1750 greenhouse gases have increased dramatically to levels not seen in hundreds of thousands of years, due to the rapid growth of the human population combined with developments in technology and agriculture. Human activities now are a powerful factor influencing Earth’s dynamic climate. The ice of the polar regions furnishes clues to the makeup of Earth’s ancient atmosphere. Ice cores that scientists have bored from the ice sheets of Greenland and Antarctica provide natural records of both temperature and atmospheric greenhouse gases going back hundreds of thousands of years. Layers in these ice cores created by seasonal snowfall patterns allow scientists to determine the age of the ice in each core. By measuring tiny air bubbles trapped in the ice and properties of the ice itself, scientists can estimate the temperature and amount of greenhouse gases in Earth’s past atmosphere at the time each layer formed. Based on this data, scientists know that greenhouse gases have now risen to levels higher than at any time in the last 650,000 years. Greenhouse gases are rising, and temperatures are following. Before the late 1800s, the average surface temperature of Earth was almost 15°C (59°F). Over the past 100 years, the average surface temperature has risen by about 0.7 Celsius degrees (1.3 Fahrenheit degrees), with most of the increase occurring since the 1970s. Scientists have linked even this amount of warming to numerous changes taking place around the world, including melting mountain glaciers and polar ice, rising sea level, more intense and longer droughts, more intense storms, more frequent heat waves, and changes in the life cycles of many plants and animals. Warming has been most dramatic in the Arctic, where temperatures have risen almost twice as much as the global average. III Global Warming in the FuturePrint this sectionScientists project global warming to continue at a rate that is unprecedented in hundreds of thousands or even millions of years of Earth’s history. They predict considerably more warming in the 21st century, depending on the level of future greenhouse gas emissions. For a scenario (possible situation) assuming higher emissions—in which emissions continue to increase significantly during the century—scientists project further warming of 2.4 to 6.4 Celsius degrees (4.3 to 11.5 Fahrenheit degrees) by the year 2100. For a scenario assuming lower emissions—in which emissions grow slowly, peak around the year 2050, and then fall—scientists project further warming of 1.1 to 2.9 Celsius degrees (1.9 to 5.2 Fahrenheit degrees) by the year 2100. Melting polar ice and glaciers, as well as warming of the oceans, expands ocean volume and raises sea level, which will eventually flood some coastal regions and even entire islands. Patterns of rainfall are expected to change, with higher latitudes (closer to the poles) projected to receive more rainfall, and subtropical areas (such as the Mediterranean and southern Africa) projected to receive considerably less. Changes in temperature and precipitation patterns may damage food crops, disrupting food production in some parts of the world. Plant and animal species will shift their ranges toward the poles or to higher elevations seeking cooler temperatures, and species that cannot do so may become extinct. Increasing levels of carbon dioxide in the atmosphere also leads to increased ocean acidity, damaging ocean ecosystems. Human beings face global warming with a huge population at risk. The potential consequences are so great that many of the world’s leading scientists—and increasingly, politicians, business leaders, and other citizens—are calling for international cooperation and immediate action to counteract the problem. Advantages and Disadvantages of global warming permalinkPositive and Negative effect of the global warming on the people and the planetIn February 2007, the United Nations released a scientific report that concludes that global warming is happening and will continue to happen for centuries. The report also stated with 90% certainty that the activity of humans has been the primary cause of increasing temperatures over the past few decades. With those conclusions and the conclusions of innumerable other scientists that global warming is here and will continue into the foreseeable future, I wanted to summarize the likely effects of global warming, into the advantages and disadvantages of global warming. First, we will look at the many disadvantages of global warming and then follow with the very small number of advantages of global warming. Disadvantages of Global WarmingOcean circulation disrupted, disrupting and having unknown effects on world climate. Higher sea level leading to flooding of low-lying lands and deaths and disease from flood and evacuation. Deserts get drier leaving to increased desertification.Changes to agricultural production that can lead to food shortages. Water shortages in already water-scarce areas. Starvation, malnutrition, and increased deaths due to food and crop shortages. More extreme weather and an increased frequency of severe and catastrophic storms. Increased disease in humans and animals. Increased deaths from heat waves. Extinction of additional species of animals and plants.

Loss of animal and plant habitats. Increased emigration of those from poorer or low-lying countries to wealthier or higher countries seeking better (or non-deadly) conditions. Additional use of energy resources for cooling needs. Increased air pollution. Increased allergy and asthma rates due to earlier blooming of plants. Melt of permafrost leads to destruction of structures, landslides, and avalanches. Permanent loss of glaciers and ice sheets. Cultural or heritage sites destroyed faster due to increased extremes. Increased acidity of rainfall. Earlier drying of forests leading to increased forest fires in size and intensity. Increased cost of insurance as insurers pay out more claims resulting from increasingly large disasters.

Advantages of Global Warming Arctic, Antarctic, Siberia, and other frozen regions of earth may

experience more plant growth and milder climates. Northwest Passage through Canada's formerly-icy north opens up to

sea transportation. Less need for energy consumption to warm cold places. Fewer deaths or injuries due to cold weather. Longer growing seasons could mean increased agricultural

production in some local areas. Mountains increase in height due to melting glaciers, becoming

higher as they rebound against the missing weight of the iceAdvantages/Benefits of Global Warming I must preface this list of advantages with the following statements: 1) I do not believe that global warming is actually happening at all. It MAY have been happening 10 years ago, though there is now evidence that the observational data is biased by proximity of temperature-recording stations to artificial heat sources (see surfacestations.org). However, even that biased data shows that the global average temperature has decreased over the last 9 years since hitting a peak in 1998, and forecasts for 2008 call for another decrease. 2) Even if global warming is (or was) happening, and even if it continues (or resumes), it is not caused by humans. Besides the current warm period, there have been three warm periods in the last 4,000 years, following a fairly regular cycle of 1,000-1,500 years. The current warming falls right in line with that cycle. Whatever the cause of those three previous warming periods, it could not have been human emissions of carbon dioxide, because we were not burning fossil fuels at any of those times. Moreover, the previous warm periods all reached temperatures well above any temperatures observed in the current warm period. So neither the warming itself nor the degree of warming is anything that cannot be explained by the same natural cycle that caused the last three warm periods. That said, I will now list the two major benefits of global warming.

Fewer cold-related deaths. Many, many more people die from cold than from heat (though the cold related deaths don't get as much media attention). The warmer it gets, the fewer people will die from cold. Moreover, global warming models all predict that the coldest times of the year, the coldest times of the day, and the coldest parts of the world will warm much more than the warmest times of the year, times of the day, and parts of the world. So, the positive effect of warming in the cold areas/times will more than offset, by a huge margin in fact, the negative effect of warming in the warm areas/times.

Increased food supply. Alarmists will tell you that global warming endangers the world's food supply. This is because they do not have a basic understanding of agronomic production. There are three things that crops need more than anything else to grow and produce high yields: heat, moisture, and carbon dioxide. Some crops can get too much heat, but even the worst predictions of global warming alarmists don't call for such temperatures. In most cases, increased temperatures will increase yields. Moreover, millions of acres that are now too cold to grow crops will become warm enough. Furthermore, in traditional crop-growing areas, it is entirely possible that, with a shorter, warmer winter, farmers will be able to plant their crops earlier and harvest them later. What this means is that they might be able to get two crops planted and harvested in one year, effectively doubling the yield. The case can be made that rainfall will decrease in some areas of the world if global warming continues. But overall, worldwide precipitation will increase. So we might have to shift farming to other areas (which is not a bad idea anyway) but there will be plenty of places where rainfall is adequate for growing crops. And even where it isn't, there's always irrigation. Carbon dioxide is obvious. Supposedly, it's the culprit behind global warming, so if global warming continues, it will be because of more carbon dioxide. But plants live on carbon dioxide - the more of it they

have, the faster they grow and the higher yields they obtain. Greenhouse growers have artificially raised CO2 levels to several times current atmospheric levels, with no ill effects (and plenty of positive effects) to the crops. All in all, global warming will probably be the best thing to happen to agricultural production since the invention of the tractor and man-made fertilizers.

If you look at global warming as the alternative to stopping global warming, then you could also list all of the disadvantages of stopping global warming as benefits of global warming itself. For example:

Freedom. Stopping global warming will force the people to hand over their rights and freedoms to an all-powerful government. This is indisputable. We will have to give up our right to drive cars, our right to electricity, our freedom of enterprise, and our right to anything else that involves the burning of fossil fuels. And we will even have to give up our freedom of speech, because, in the name of saving the planet, the government cannot tolerate any skepticism about global warming.

Prosperity. Stopping global warming (if the alarmists are correct about its causes) will require a ban on (or at least a massive reduction in) the burning of fossil fuels. Fossil fuels are what drives our economy. Without them, everything will grind to a halt quite quickly. Businesses will fail. Jobs will disappear. The economy will go into the tank.

Human comfort, convenience, and entertainment. One of the rights we will have to give up is the right to use electricity. We won't be able to use our stoves, our lights, our air conditioners, our heaters, our dishwashers, our hot water heaters, our televisions, our computers, etc. Are those things that you want to do without? Can you even survive without those things?

Food supply. I've already mentioned how the food supply will increase dramatically under global warming. But any effort to stop global warming will cause a huge decrease in the food supply. Growing crops requires tractors, and tractors use fossil fuels. Except they won't be using fossil fuels anymore if we are going to stop global warming. Tractors will be replaced with mules and other draft animals. Not only will agricultural production drop by 80-90%, but much of what is left will be required to feed the draft animals. And what little food is grown will never make it to the places where people live in massive numbers because that too requires burning fossil fuels. There will be massive starvation around the world, especially in large urban areas and other places where no food is grown.

World Peace. We already know that China and India are never going to go along with reducing their carbon dioxide emissions. But no plan to stop global warming will work without their participation. So what are we going to do about that? We're going to go to war with them, that's what we are going to do. The Arab nations will ally themselves with China and India, because that will be the only customers they have for their oil. The two sides will be fairly evenly matched, which will make for a very long, very bloody world war. There will be tens of millions of deaths over years, perhaps decades, in this World War III, caused by global warming alarmism. Not to mention that the war will defeat its own purpose anyway, because of the massive burning of fossil fuels that will be required to wage that war.

Avoiding World-wide Nuclear Armageddon. It is very, very likely that the WW3 mentioned in the previous point will, eventually, go nuclear. Then everything is for naught. Oh sure, global warming will be stopped, because of the planet-covering cloud of radioactive dust, smoke, and soot, blocking 90% of the sunlight from reaching the surface. But between the immediate effect of the missiles themselves and the delayed effects of radiation poisioning, the vast majority of the earth's human population will be gone (and for those of you more worried about the prescious polar bears, they'll be gone too).

My point is that, even if global warming is happening, even if we are causing it, and even if we can stop it, there is no proof that doing so will benefit us at all. In fact, one can easily make the case (as I have) that the benefits of global warming will outweigh the disadvantages. Moreover, the case can also easily be made that the sacrifices we will have to make to stop global warming are far, far worse than global warming itself. Are you willing to give up your freedom and comfort to stop global warming? Are you willing to sacrifice the world's economic prosperity, and even its food supply? Are you willing to precipitate a massive world war, probably ending in nuclear Armageddon? If so, then let's just launch the nukes now and get it over with. Because I, for one, don't want to live through the loss of freedom, comfort, prosperity, and food that will otherwise precede the Armageddon.

"Ss501 Warning lyrics"Jujo angeji hangsang guredushidalkomhan yegi gojidoen nunmullo

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