What is Global Warming?
371905
Global warming is a term used to describe the trend of increases in the average temperature of the Earth's atmosphere and oceans that has been observed in recent decades. The scientific opinion on climate change, as expressed in the UN Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report in 2001 and explicitly endorsed by the national science academies of the G8 nations in 2005, is that the average global temperature has risen 0.6 ± 0.2 °C since the late 19th century, and that it is likely that "most of the warming observed over the last 50 years is attributable to human activities" [1]. The increased volumes of carbon dioxide and other greenhouse gases released by the burning of fossil fuels, land clearing and agriculture, and other human activities, are the primary sources of the human-induced component of warming. The natural greenhouse effect keeps the Earth about 33 °C warmer than it otherwise would be; adding carbon dioxide to a planet's atmosphere, with no other changes, will make that planet's surface warmer.\n\nObservational sensitivity studies [2] [3] and climate models referenced by the IPCC predict that global temperatures may increase by 1.4 to 5.8 °C between 1990 and 2100.\n\nThe range of uncertainty results in large part from not knowing the volume of future carbon dioxide emissions. In addition, there is uncertainty about the accuracy of the underlying climate models.\n\nThe increase in global temperatures is expected to result in other climate changes including rises in sea level and changes in the amount and pattern of precipitation. Such changes may increase the frequency and intensity of extreme weather events such as floods, droughts, heat waves, and hurricanes, change agricultural yields, cause glacier retreat, reduced summer streamflows, or contribute to biological extinctions. Although warming is expected to affect the number and magnitude of these events, it is difficult to connect any particular event to global warming.\n\nAlthough most studies focus on the period up to 2100, warming would be expected to continue past then, since CO2 has a long average atmospheric lifetime [4]. Also, Climate commitment studies indicate that there is a further warming of perhaps 0.5 °C to 1.0 °C — already committed but not yet realised.There are only a few scientists that contest the view that humanity's actions have played a significant role in increasing recent temperatures. However, uncertainties do exist regarding how much climate change should be expected in the future, and a hotly-contested political and public debate exists over what, if anything, should be done to reduce or reverse future warming, and how to cope with the consequences.
1170026
Global warming started long before the "Industrial Revolution" and the invention of the internal combustion engine. Global warming began 18,000 years ago as the earth started warming its way out of the Pleistocene Ice Age-- a time when much of North America, Europe, and Asia lay buried beneath great sheets of glacial ice.\n\nEarth's climate and the biosphere have been in constant flux, dominated by ice ages and glaciers for the past several million years. We are currently enjoying a temporary reprieve from the deep freeze.\n\nApproximately every 100,000 years Earth's climate warms up temporarily. These warm periods, called interglacial periods, appear to last approximately 15,000 to 20,000 years before regressing back to a cold ice age climate. At year 18,000 and counting our current interglacial vacation from the Ice Age is much nearer it's end than it's beginning.\n\nGlobal warming during Earth's current interglacial warm period has greatly altered our environment and the distribution and diversity of all life. For example:\n\n\n Approximately 15,000 years ago the earth had warmed sufficiently to halt the advance of glaciers, and sea levels worldwide began to rise.\n\n By 8,000 years ago the land bridge across the Bearing Strait was drowned, cutting off the migration of men and animals to North America.\n\n Since the end of the Ice Age, Earth's temperature has risen approximately 16 degrees F and sea levels have risen a total of 300 feet ! Forests have returned where once there was only ice.\n\nDuring ice ages our planet is cold, dry, and inhospitable-- supporting few forests but plenty of glaciers and deserts. Like a spread of collosal bulldozers, glaciers have scraped and pulverized vast stretches of Earth's surface and completely destroyed entire regional ecosystems not once, but several times. During Ice Ages winters were longer and more severe and ice sheets grew to tremendous size, accumulating to thicknesses of up to 8,000 feet!. They moved slowly from higher elevations to lower-- driven by gravity and their tremendous weight. They left in their wake altered river courses, flattened landscapes, and along the margins of their farthest advance, great piles of glacial debris.\n\nDuring the last 3 million years glaciers have at one time or another covered about 29% of Earth's land surface or about 17.14 million square miles (44.38 million sq. km.) . What did not lay beneath ice was a largely cold and desolate desert landscape, due in large part to the colder, less-humid atmospheric conditions that prevailed.\n\nDuring the Ice Age summers were short and winters were brutal. Animal life and especially plant life had a very tough time of it. Thanks to global warming, that has all now changed, at least temporarily.\n\nThje maximum CO2 level was 2% over 2.5 million yrs back, at least scientists say that!!
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Natural warming/cooling of the earth as it progresses through it's life cycle.  Effects of civilization on global warming may be measurable, but it is hardly signifigant when compared to the forces of nature and the tendency of our planet's temperature to fluctuate through ice ages and periods of warmer climes.
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If you mean global warming, it's the scientific observation that the earth's temperature is rising over a period of time This is resulting in polar melting, raising the ocean level and affecting other weather patterns.
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Short Answer: Carbon dioxide.\n\nLong answer:\nGlobal warming is the observed increase in the average temperature of the Earth's atmosphere and oceans in recent decades.\n\nThe prevailing scientific opinion on climate change is that "most of the warming observed over the last 50 years is attributable to human activities".\n\nThe increased amounts of carbon dioxide (CO2) and other greenhouse gases (GHGs) are the primary causes of the human-induced component of warming. They are released by the burning of fossil fuels, land clearing and agriculture, etc. and lead to an increase in the greenhouse effect. The first speculation that a greenhouse effect might occur was by the Swedish chemist Svante Arrhenius in 1897, although it did not become a topic of popular debate until some 90 years later.
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Global warming is due to the huge quantity of some kind of gaz that human activity ejects in the atmospher. That gaz in itself does not warm, but it has indirect effects: destroying the earth's protection towards these sunshines and keeping the heat of these sunshines into the earth's atmospher.\nWhy people don't care much about it? It's because they don't realize that the earth as they know it could drastically change. Until now, it took billions of years to change, so human lifetime (and even the complete human History!!!) isn't much compared to the usual scale of big climate changes. But the earth human population, its activity and its ability to pollute have increased so much that it has become possible for humanity to go straight into a wall without even realizing it!!!
359692
The radiations emitted from the sun and also the earth are usually blocked by layers of atmospheric gases and prevent them from escaping into space.This causes 'GLOBAL WARMING'-due to the reflected radiations.This is also known as 'GREEN HOUSE EFFECT'.
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Pollution caused by exhaust gases plus CO2 blocks the radiation of heat from the earth into the universe. Thus global warming will cause the sea level to rise as much as 2 kilometers high in the near future.
1154290
climate change is a natural effect. Global Warming is caused by man.
342379
Global warming is a term used to describe the trend of increases in the average temperature of the Earth's atmosphere and oceans that has been observed in recent decades. The scientific opinion on climate change, as expressed in the UN Intergovernmental Panel on Climate Change (IPCC) Third Assessment Report in 2001 and explicitly endorsed by the national science academies of the G8 nations in 2005, is that the average global temperature has risen 0.6 ± 0.2 °C since the late 19th century, and that it is likely that "most of the warming observed over the last 50 years is attributable to human activities" [1]. The increased volumes of carbon dioxide and other greenhouse gases released by the burning of fossil fuels, land clearing and agriculture, and other human activities, are the primary sources of the human-induced component of warming. The natural greenhouse effect keeps the Earth about 33 °C warmer than it otherwise would be; adding carbon dioxide to a planet's atmosphere, with no other changes, will make that planet's surface warmer.\n\nObservational sensitivity studies [2] [3] and climate models referenced by the IPCC predict that global temperatures may increase by 1.4 to 5.8 °C between 1990 and 2100.\n\nThe range of uncertainty results in large part from not knowing the volume of future carbon dioxide emissions. In addition, there is uncertainty about the accuracy of the underlying climate models.\n\nThe increase in global temperatures is expected to result in other climate changes including rises in sea level and changes in the amount and pattern of precipitation. Such changes may increase the frequency and intensity of extreme weather events such as floods, droughts, heat waves, and hurricanes, change agricultural yields, cause glacier retreat, reduced summer streamflows, or contribute to biological extinctions. Although warming is expected to affect the number and magnitude of these events, it is difficult to connect any particular event to global warming.\n\nAlthough most studies focus on the period up to 2100, warming would be expected to continue past then, since CO2 has a long average atmospheric lifetime [4]. Also, Climate commitment studies indicate that there is a further warming of perhaps 0.5 °C to 1.0 °C — already committed but not yet realized.\n \nThere are only a few scientists that contest the view that humanity's actions have played a significant role in increasing recent temperatures. However, uncertainties do exist regarding how much climate change should be expected in the future, and a hotly-contested political and public debate exists over what, if anything, should be done to reduce or reverse future warming, and how to cope with the consequences.
296292
global warming is real. its extremey or may not be related toinitially global warming causes the polar caps to melong termea water to rise and become lower in saline concentrations.\nthe lower the salt content the less the currents of the ocean flow and the COLDER the winters get (warm water not moving away from the equator) \nin natural cycles the more extreeme cold kills off organisms initally resulting in HIGHER greenhouse gases, but longterm the "ice age" that follows will leave less life (and death) reducing the overall emissions. this also increases the amount of icebound water increasing the salinity in the oceans returning the currenty\n\nSo You decide on the cause but it is real and geologically recorded again and again.
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http://www.ieer.org/ensec/no-5/globwarm.html\n\nhttp://www.tierramerica.net/2001/0311/conect.shtml\n\nhttp://www.epa.gov/climatechange/glossary.html\n\nGlobal Warming\nGlobal warming is an average increase in the temperature of the atmosphere near the Earth's surface and in the troposphere, which can contribute to changes in global climate patterns. Global warming can occur from a variety of causes, both natural and human induced. In common usage, "global warming" often refers to the warming that can occur as a result of increased emissions of greenhouse gases from human activities. See climate change, greenhouse effect, enhanced greenhouse effect, radiative forcing, troposphere.\n\n\nSource: 2006 U.S. Inventory of Greenhouse Gas Emissions and Sinks: Fast Facts (PDF, 2 pp., 220 KB, About PDF)\nGlobal Warming Potential (GWP)\nGlobal Warming Potential (GWP) is defined as the cumulative radiative forcing effects of a gas over a specified time horizon resulting from the emission of a unit mass of gas relative to a reference gas. The GWP-weighted emissions of direct greenhouse gases in the U.S. Inventory are presented in terms of equivalent emissions of carbon dioxide (CO2), using units of teragrams of carbon dioxide equivalents (Tg CO2 Eq.).\n\nConversion: Tg = 109 kg = 106 metric tons = 1 million metric tons\n\nThe molecular weight of carbon is 12, and the molecular weight of oxygen is 16; therefore, the molecular weight of CO2 is 44 (i.e., 12+[16 x 2]), as compared to 12 for carbon alone. Thus, carbon comprises 12/44ths of carbon dioxide by weight.\n\nSee radiative forcing, carbon dioxide equivalent.\n\nGreenhouse Effect\nTrapping and build-up of heat in the atmosphere (troposphere) near the Earth’s surface. Some of the heat flowing back toward space from the Earth's surface is absorbed by water vapor, carbon dioxide, ozone, and several other gases in the atmosphere and then reradiated back toward the Earth’s surface. If the atmospheric concentrations of these greenhouse gases rise, the average temperature of the lower atmosphere will gradually increase. See greenhouse gas, anthropogenic, climate, global warming.7\n\nGreenhouse Gas (GHG)\nAny gas that absorbs infrared radiation in the atmosphere. Greenhouse gases include, but are not limited to, water vapor, carbon dioxide (CO2), methane (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs), hydrochlorofluorocarbons (HCFCs), ozone (O3 ), hydrofluorocarbons (HFCs), perfluorocarbons (PFCs), and sulfur hexafluoride (SF6). See carbon dioxide, methane, nitrous oxide, ozone, chlorofluorocarbons, hydrochlorofluorocarbons, hydrofluorocarbons, perfluorocarbons, sulfur hexafluoride.7\n\n\n\n\ngreenhouse effect  a warming process that balances Earth's cooling processes and helps maintain an average global temperature of approximately 60 degrees Fahrenheit. During this process, sunlight enters Earths atmosphere as short wave radiation. The radiation is absorbed by Earth's surface. The planet becomes heated and emits long wave radiation toward the atmosphere. In the atmosphere, some of the long wave radiation is absorbed by certain gases called greenhouse gases.  Each molecule of greenhouse gas becomes energized and emits heat energy in all directions.  By radiating heat energy toward Earth , greenhouse gases increase Earth's temperature. Note that the warming mechanism for the "greenhouse effect" is NOT exactly the same as the warming mechanism of greenhouse walls. While greenhouse gases absorb long wave radiation then emit heat energy it in all directions, greenhouse walls physically trap heat inside of greenhouses and prevent it from escaping to the atmosphere.\n\ngreenhouse gases  certain gases in the Earth's atmosphere that absorb some of the outgoing long wave radiation, or heat energy (see greenhouse effect). These gases include carbon dioxide (CO2), methane (CH4), and nitrous oxide (N2O).
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An increase in solar radiation due to slight variations in the Earth's orbit and orbital tilt.  These are regular variations and also coincide with greater and lesser ice ages depending on slight variations in solar output.  \n\nWhile "global warming" is an issue for sudden climate change, it probably had little influence on the most recent ice age.\n\nIn fact there have been many "mini" ice ages in recorded history, most notably around 1300 AD where really extreme cold conditions led to some very interesting technological developments such as the chimney.\n\nSee the link below.
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it is the greenhouse effect that causes global warming.
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Exactly none. There is a finite amount of energy stored on the planet in the form of fossil fuels. Burning it releases this energy. You cannot add more. There has been heat RELEASED by the burning of fossil fuels onthe planet, which many people believe causes global warming. The only heat energy added to the planet is solar energy.
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Global warming is the opposite of global cooling.  The Earth has gone through at least 3 episodes of cooling/warming.  Where I am sitting now was once under about 1000 feet of ice.  The Earth warmed up enough to melt all that ice -- and this was way before there were any cars or industry (or even people).  Global warming is NOT caused by people living their lives and producing things. People may have an effect on the rate, but we are not the CAUSE. BTW, the ozone layer hole, which expands and contracts, has no direct effect on global cooling/warming.
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Global warming is an increase in the average temperature of the Earth's atmosphere and oceans. The term is also used for the scientific theory of anthropogenic global warming, which attributes much of the recently observed and projected global warming to a human-induced intensification of the greenhouse effect.