Green house gases

Hi everyone here is some info about grenn house gases




measuring the Impact of Greenhouse




Human actions - such as burning fossil fuels and land clearing - are increasing the concentration of greenhouse gases in the atmosphere, in particular concentrations of carbon dioxide. This has led to increasing average temperatures on the Earth's surface and weather and climate changes.
Observed changes that have already occurred as a result of changes to the atmosphere include increased frequency of extreme weather events such as floods, droughts and cyclones, rises in sea level, changing rainfall patterns, decreasing sea ice and melting glaciers. Further climate change is anticipated as concentrations of greenhouse gases in the atmosphere continue to rise. In its Third Assessment Report, the Intergovernmental Panel on Climate Change concludes that the impacts of climate change will become increasingly detrimental for more of the world's regions and systems as the extent of global warming increases.
The evidence of human-induced global warming and climate change is strong. However, many uncertainties still remain. The interaction of the multiple changes occurring and their potential flow-on effect is not completely understood and further research is needed to monitor the current situation and improve predictions for the future.
Cooperative Research Centre for Greenhouse Accounting research is making significant contributions to world knowledge about the impacts of climate change. The Centre was the first to confirm in Australia that, contrary to widespread expectations, potential evaporation from the soil and land-based water bodies such as lakes is decreasing in most places. They also discovered the reason for this - more cloud cover and increased air pollution has led to a reduction in direct sunlight reaching the Earth's surface. Changes in evaporation rates combined with changing rainfall patterns and reduced direct sunlight may favour long-lived, woody plants live trees over shorter lived plants, thereby changing habitats, ecosystems, biodiversity and the flows of greenhouse gases.
The CRC is studying how plants in Australia will be affected by continuing increases in carbon dioxide concentrations in the atmosphere and rising temperatures and finding some surprising results. Reducing Greenhouse
Global warming and climate change as a result of human-induced increases in greenhouse gases are arguably the biggest threat facing the world's population. Predicted impacts include higher temperatures; increased extreme weather events such as floods, droughts, cyclones and tornadoes; rising sea levels; extinction of species and increases in disease.
Australia's human-induced emissions of greenhouse gases are among the highest per capita in the world at around 27 tonnes per person per year, comparable with those from North America and New Zealand but higher than those from countries across Europe.
The main human activities that produce greenhouse gases are:
Burning fossil fuels - the use of oil, coal and natural gases to provide energy for industrial processes, transportation, agriculture, heating, lighting etc.
Clearing and burning forests
Farming and intensive agriculture practices
Decomposing waste in landfill rubbish tips
Industrial processes that create damaging atmospheric pollutants
We must find ways to reduce the amount of greenhouse gases finding their way into the atmosphere. Until we do, global warming will continue, climate will change further, and the accompanying extremes of damaging weather will become greater and more frequent.
The Cooperative Research Centre for Greenhouse Accounting is investigating how greenhouse gases are removed from the atmosphere and stored in 'sinks' such as plants and soils. It is developing tools to predict how new farming and forestry methods, different land uses and environmental changes will affect the greenhouse problem. It is applying the new knowledge to assist policy makers and farmers, graziers, foresters and land managers to choose options which minimise concentrations of greenhouse gases in the atmosphere.

What Are Greenhouse Gases?Many chemical compounds found in the Earth’s atmosphere act as “greenhouse gases.” These gases allow sunlight to enter the atmosphere freely. When sunlight strikes the Earth’s surface, some of it is reflected back towards space as infrared radiation (heat). Greenhouse gases absorb this infrared radiation and trap the heat in the atmosphere. Over time, the amount of energy sent from the sun to the Earth’s surface should be about the same as the amount of energy radiated back into space, leaving the temperature of the Earth’s surface roughly constant.
Many gases exhibit these “greenhouse” properties. Some of them occur in nature (water vapor, carbon dioxide, methane, and nitrous oxide), while others are exclusively human-made (like gases used for aerosols).

Why Are Atmospheric Levels Increasing?
Levels of several important greenhouse gases have increased by about 25 percent since large-scale industrialization began around 150 years ago (Figure 1). During the past 20 years, about three-quarters of human-made carbon dioxide emissions were from burning fossil fuels.
Figure 1. Trends in Atmospheric Concentrations and Anthropogenic Emissions of Carbon Dioxide
Concentrations of carbon dioxide in the atmosphere are naturally regulated by numerous processes collectively known as the “carbon cycle” (Figure 2). The movement (“flux”) of carbon between the atmosphere and the land and oceans is dominated by natural processes, such as plant photosynthesis. While these natural processes can absorb some of the net 6.1 billion metric tons of anthropogenic carbon dioxide emissions produced each year (measured in carbon equivalent terms), an estimated 3.2 billion metric tons is added to the atmosphere annually. The Earth’s positive imbalance between emissions and absorption results in the continuing growth in greenhouse gases in the atmosphere.
Figure 2. Global Carbon Cycle (Billion Metric Tons Carbon)
What Effect Do Greenhouse Gases Have on Climate Change?
Given the natural variability of the Earth’s climate, it is difficult to determine the extent of change that humans cause. In computer-based models, rising concentrations of greenhouse gases generally produce an increase in the average temperature of the Earth. Rising temperatures may, in turn, produce changes in weather, sea levels, and land use patterns, commonly referred to as “climate change.”
Assessments generally suggest that the Earth’s climate has warmed over the past century and that human activity affecting the atmosphere is likely an important driving factor. A National Research Council study dated May 2001 stated, “Greenhouse gases are accumulating in Earth’s atmosphere as a result of human activities, causing surface air temperatures and sub-surface ocean temperatures to rise. Temperatures are, in fact, rising. The changes observed over the last several decades are likely mostly due to human activities, but we cannot rule out that some significant part of these changes is also a reflection of natural variability.”
However, there is uncertainty in how the climate system varies naturally and reacts to emissions of greenhouse gases. Making progress in reducing uncertainties in projections of future climate will require better awareness and understanding of the buildup of greenhouse gases in the atmosphere and the behavior of the climate system.
What Are the Sources of Greenhouse Gases?
In the U.S., our greenhouse gas emissions come mostly from energy use. These are driven largely by economic growth, fuel used for electricity generation, and weather patterns affecting heating and cooling needs. Energy-related carbon dioxide emissions, resulting from petroleum and natural gas, represent 82 percent of total U.S. human-made greenhouse gas emissions (Figure 3). The connection between energy use and carbon dioxide emissions is explored in the box on the reverse side (Figure 4).
Figure 3. U.S. Anthropogenic Greenhouse Gas Emissions by Gas, 2001 (Million Metric Tons of Carbon Equivalent)

Figure 4. U.S. Primary Energy Consumption and Carbon Dioxide Emissions, 2001
Another greenhouse gas, methane, comes from landfills, coal mines, oil and gas operations, and agriculture; it represents 9 percent of total emissions. Nitrous oxide (5 percent of total emissions), meanwhile, is emitted from burning fossil fuels and through the use of certain fertilizers and industrial processes. Human-made gases (2 percent of total emissions) are released as byproducts of industrial processes and through leakage.
What Is the Prospect for Future Emissions?
World carbon dioxide emissions are expected to increase by 1.9 percent annually between 2001 and 2025 (Figure 5). Much of the increase in these emissions is expected to occur in the developing world where emerging economies, such as China and India, fuel economic development with fossil energy. Developing countries’ emissions are expected to grow above the world average at 2.7 percent annually between 2001 and 2025; and surpass emissions of industrialized countries near 2018.
Figure 5. World Carbon Dioxide Emissions by Region, 2001-2025(Million Metric Tons of Carbon Equivalent)
The U.S. produces about 25 percent of global carbon dioxide emissions from burning fossil fuels; primarily because our economy is the largest in the world and we meet 85 percent of our energy needs through burning fossil fuels. The U.S. is projected to lower its carbon intensity by 25 percent from 2001 to 2025, and remain below the world average (Figure 6).
Figure 6. Carbon Intensity by Region, 2001-2025(Metric Tons of Carbon Equivalent per Million $1997)
Greenhouse gases (GHGs) are gaseous components of the atmosphere that contribute to the "greenhouse effect". Although uncertainty exists about exactly how earth's climate responds to these gases, global temperatures are rising. [1] Some greenhouse gases occur naturally in the atmosphere, while others result from human activities. Naturally occuring greenhouse gases include water vapour, carbon dioxide, methane, nitrous oxide, and ozone. Certain human activities, however, add to the levels of most of these naturally occurring gases. [2]
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The "Greenhouse Effect"
Main article: Greenhouse effect
When sunlight reaches the Earth's surface, some is absorbed and warms the earth. Because the earth is much cooler than the sun, it radiates energy at much longer wavelengths than the sun (see Black body radiation and Wien's displacement law); some of these longer wavelengths are absorbed by greenhouse gases in the atmosphere before they are lost to space. The absorption of this longwave radiant energy warms the atmosphere (the atmosphere also is warmed by transfer of sensible and latent heat from the surface). Greenhouse gases also emit longwave radiation both upward to space and downward to the surface. The downward part of this longwave radiation emitted by the atmosphere is the "greenhouse effect." The term is in fact a misnomer, as this process is not the primary mechanism that warms greenhouses.
The major natural greenhouse gases are water vapor, which causes about 36-70% of the greenhouse effect on Earth (not including clouds); carbon dioxide, which causes 9-26%; methane, which causes 4-9%, and ozone, which causes 3-7%. Note that it is not really possible to assert that a certain gas causes a certain percentage of the greenhouse effect, because the influences of the various gases are not additive. (The higher ends of the ranges quoted are for the gas alone; the lower ends, for the gas counting overlaps.)[3] [4]
Other greenhouse gases include, but are not limited to, nitrous oxide, sulfur hexafluoride, hydrofluorocarbons, perfluorocarbons and chlorofluorocarbons (see IPCC list of greenhouse gases).
The major atmospheric constituents (N2 and O2) are not greenhouse gases, because homonuclear diatomic molecules (e.g. N2, O2, H2) neither absorb nor emit infrared radiation as there is no net change in the dipole moment of these molecules.
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Anthropogenic greenhouse gases


Global greenhouse gas emissions broken down into 8 different sectors for the year 2000.
The concentrations of several greenhouse gases have increased over time.[5] Human activity raises levels of greenhouse gases primarily by releasing carbon dioxide, but human influences on other gases, e.g., methane, are not negligible.[6] Some of the main sources of greenhouse gases due to human activity include:
burning of fossil fuels and deforestation leading to higher carbon dioxide concentrations;
livestock and paddy rice farming, land use and wetland changes, pipeline losses, and covered vented landfill emissions leading to higher methane atmospheric concentrations. Many of the newer style fully vented septic systems that enhance and target the fermentation process also are major sources of atmospheric methane;
use of CFCs in refrigeration systems, and use of CFCs and halons in fire suppression systems and manufacturing processes.
According to the global warming trend, greenhouse gases from industry and agriculture have played a major role in the recently observed global warming. Carbon dioxide, methane, nitrous oxide and three groups of fluorinated gases are the subject of the Kyoto Protocol, which entered into force in 2005. Methane, nitrous oxide and ozone-depleting gases are also taken into account in the international agreements, but not ozone. Note that ozone depletion has only a minor role in greenhouse warming, though the two processes often are confused in the popular media.
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The role of water vapor


Increasing water vapor at Boulder, Colorado.
Water vapor is a natural greenhouse gas and accounts for the largest percentage of the greenhouse effect. Water vapor concentrations fluctuate regionally, but human activity does not directly affect water vapor concentrations except at very local scales.
In climate models an increase in atmospheric temperature caused by the greenhouse effect due to anthropogenic gases will in turn lead to an increase in the water vapor content of the troposphere, with approximately constant relative humidity. The increased water vapor in turn leads to an increase in the greenhouse effect and thus a further increase in temperature; the increase in temperature leads to still further increase in atmospheric water vapor; and the feedback cycle continues until equilibrium is reached. Thus water vapor acts as a positive feedback to the forcing provided by human-released greenhouse gases such as CO2 (but has never, so far, acted on Earth as part of a runaway feedback). Changes in the water vapor may also have indirect effects via cloud formation.
Most scientists agree that the overall effect of the direct and indirect feedbacks caused by increased water vapor content of the atmosphere significantly enhances the initial warming that caused the increase - that is, it is a strong positive feedback.([2], see B7).
Water vapor is a definite part of the greenhouse gas equation even though not under direct human control: Intergovernmental Panel on Climate Change (IPCC) TAR chapter lead author Michael Mann considers citing "the role of water vapor as a greenhouse gas" to be "extremely misleading" as water vapor can not be controlled by humans [3]; see also [4] and [5]. The IPCC discusses the water vapor feedback in more detail [6].
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Increase of greenhouse gases
Based on measurements from Antarctic ice cores, it is widely accepted that just before industrial emissions began, atmospheric CO2 levels were about 280 µL/L (note the units µL/L are identical to parts per million by volume). From the same ice cores it appears that CO2 concentrations have stayed between 260 and 280 µL/L during the preceding 10,000 years. Some studies[7], using evidence from stomata of fossilized leaves, have found greater variability with CO2 levels above 300 µL/L during the period 7-10 kyr ago, though others have argued that these findings more likely reflect calibration/contamination problems rather than actual CO2 variability[8][9].
Since the beginning of the Industrial Revolution, the concentrations of many of the greenhouse gases have increased. Most of the increase in carbon dioxide occurred after 1945. Those with the largest radiative forcing are:
Relevant to radiative forcing
Gas
Current (1998) Amount by volume
Increase over pre-industrial (1750)
Percentage increase
Radiative forcing (W/m2)
Carbon dioxide
365 ppm
87 ppm
31%
1.46
Methane
1,745 ppb
1,045 ppb
150%
0.48
Nitrous oxide
314 ppb
44 ppb
16%
0.15


Global carbon dioxide emissions 1751–2000.
Relevant to both radiative forcing and ozone depletion; all of the following have no natural sources and hence zero amounts pre-industrial
Gas
Current (1998)Amount by volume
Radiative forcing(W/m2)
CFC-11
268 ppt
0.07
CFC-12
533 ppt
0.17
CFC-113
84 ppt
0.03
Carbon tetrachloride
102 ppt
0.01
HCFC-22
69 ppt
0.03
(Source: IPCC radiative forcing report 1994 updated (to 1998) by IPCC TAR table 6.1 [7][8]).
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Removal from the atmosphere and global warming potential


Major greenhouse gas trends
Aside from water vapor near the surface, which has a residence time of days, most greenhouse gases take a very long time to leave the atmosphere. It is not easy to know with precision how long, because the atmosphere is a very complex system. However, there are estimates of the duration of stay, i.e., the time which is necessary so that the gas disappears from the atmosphere, for the principal ones. Greenhouse gases can be removed from the atmosphere by various processes:
as a consequence of a physical change (condensation and precipitation remove water vapor from the atmosphere).
as a consequence of chemical reactions within the atmosphere. This is the case for methane. It is oxidized by reaction with naturally occurring hydroxyl radical, OH· and degraded to CO2 and water vapor at the end of a chain of reactions (the contribution of the CO2 from the oxidation of methane is not included in the methane GWP). This also includes solution and solid phase chemistry occurring in atmospheric aerosols.
as a consequence of a physical interchange at the interface between the atmosphere and the other compartments of the planet. An example is the mixing of atmospheric gases into the oceans at the boundary layer.
as a consequence of a chemical change at the interface between the atmosphere and the other compartments of the planet. This is the case for CO2, which is reduced by photosynthesis of plants, and which, after dissolving in the oceans, reacts to form carbonic acid and bicarbonate and carbonate ions (see ocean acidification).
as a consequence of a photochemical change. Halocarbons are dissociated by UV light releasing Cl· and F· as free radicals in the stratosphere with harmful effects on ozone (halocarbons are generally too stable to disappear by chemical reaction in the atmosphere).
as a consequence of dissociative ionization caused by high energy cosmic rays or lightning discharges, which break molecular bonds. For example, lightning forms N atoms from N2 which then react with O2 to form NO2.
Two scales can be used to describe the effect of different gases in the atmosphere. The first, the atmospheric lifetime, describes how long it takes to restore the system to equilibrium following a small increase in the concentration of the gas in the atmosphere. Individual molecules may interchange with other reservoirs such as soil, the oceans, and biological systems, but the mean lifetime refers to the decaying away of the excess. One may encounter claims that the atmospheric lifetime of CO2 is only a few years because that is the average time for any CO2 molecule to stay in the atmosphere before mixing into the ocean, being transformed to oxygen by photosynthesis, etc. This ignores the balancing fluxes of CO2 into the atmosphere from the other reservoirs. It is the net concentration changes of the various greenhouse gases by all sources and sinks that determines atmospheric lifetime, not just the removal processes.
The second scale is global warming potential (GWP). The GWP depends on both the efficiency of the molecule as a greenhouse gas and its atmospheric lifetime. GWP is measured relative to the same mass of CO2 and evaluated for a specific timescale. Thus, if a molecule has a high GWP on a short time scale (say 20 years) but has only a short lifetime, it will have a large GWP on a 20 year scale but a small one on a 100 year scale. Conversely, if a molecule has a longer atmospheric lifetime than CO2 its GWP will increase with time.
Examples of the atmospheric lifetime and GWP for several greenhouse gases include:
CO2 has a variable atmospheric lifetime (approximately 200-450 years for small perturbations). Recent work indicates that recovery from a large input of atmospheric CO2 from burning fossil fuels will result in an effective lifetime of tens of thousands of years.[10][11] Carbon dioxide is defined to have a GWP of 1 over all time periods.
Methane has an atmospheric lifetime of 12 ± 3 years and a GWP of 62 over 20 years, 23 over 100 years and 7 over 500 years. The decrease in GWP associated with longer times is associated with the fact that the methane is degraded to water and CO2 by chemical reactions in the atmosphere.
Nitrous oxide has an atmospheric lifetime of 120 years and a GWP of 296 over 100 years.
CFC-12 has an atmospheric lifetime of 100 years and a GWP(100) of 10600.
HCFC-22 has an atmospheric lifetime of 12.1 years and a GWP(100) of 1700.
Tetrafluoromethane has an atmospheric lifetime of 50,000 years and a GWP(100) of 5700.
Sulfur hexafluoride has an atmospheric lifetime of 3,200 years and a GWP(100) of 22000.
Source : IPCC, table 6.7.
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Related effects


MOPITT 2000 global carbon monoxide
Carbon monoxide has an indirect radiative forcing effect by elevating concentrations of methane and tropospheric ozone through chemical reactions with other atmospheric constituents (e.g., the hydroxyl radical, OH) that would otherwise destroy them. Carbon monoxide is created when carbon-containing fuels are burned incompletely. Through natural processes in the atmosphere, it is eventually oxidized to carbon dioxide. Carbon monoxide concentrations are both short-lived in the atmosphere and spatially variable.
Another potentially important indirect effect comes from methane, which in addition to its direct radiative impact also contributes to ozone formation. Shindell et al (2005)[12] argue that the contribution to climate change from methane is at least double previous estimates as a result of this effect[9].
One of the related effects of global warming is that as the level of carbon dioxide in the atmosphere increases, so does the acidity of the oceans.
One of the more alarming potential correlations with Greenhouse gases and Global Warming is the notion of Global dimming which seems to have masked the effect of Global Warming due to the Earth getting cooler through Global Dimming.
Greenhouse Gases and Society
by Nick Hopwood and Jordan Cohen
Greenhouse gases naturally blanket the Earth and keep it about 33 degrees Celsius warmer than it would be without these gases in the atmosphere. This is called the ?Greenhouse Effect?. Over the past century, the Earth has increased in temperature by about .5 degrees Celsius and many scientists believe this is because of an increase in concentration of the main greenhouse gases: carbon dioxide, methane, nitrous oxide, and fluorocarbons. People are now calling this climate change over the past century the beginning of? Global Warming.? Fears are that if people keep producing such gases at increasing rates, the results will be negative in nature, such as more severe floods and droughts, increasing prevalence of insects, sea levels rising, and Earth's precipitation may be redistributed. These changes to the environment will most likely cause negative effects on society, such as lower health and decreasing economic development. However, some scientists argue that the global warming we are experiencing now is a natural phenomenon, and is part of Earth's natural cycle. Presently, nobody can prove if either theory is correct, but one thing is certain; the world has been emitting greenhouse gases at extremely high rates and has shown only small signs of reducing emissions until the last few years. After the 1997 Kyoto Protocol, the world has finally taken the first step in reducing emissions.
The Greenhouse Effect
The "greenhouse effect" is the heating of the Earth due to the presence of greenhouse gases. It is named this way because of a similar effect produced by the glass panes of a greenhouse. Shorter-wavelength solar radiation from the sun passes through Earth's atmosphere, then is absorbed by the surface of the Earth, causing it to warm. Part of the absorbed energy is then reradiated back to the atmosphere as long wave infared radiation. Little of this long wave radiation escapes back into space; the radiation cannot pass through the greenhouse gases in the atmosphere. The greenhouse gases selectively transmit the infared waves, trapping some and allowing some to pass through into space. The greenhouse gases absorb these waves and reemits the waves downward, causing the lower atmosphere to warm.(www.eb.com:180)
Diagram to help explain the process of global warming and how greenhouse gases create the "greenhouse effect"
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Greenhouse Gases
This graph shows the distribution of GHG in Earth's atmosphere. Carbon Dioxide is clearly the majority.
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Carbon Dioxide
Carbon Dioxide (CO2) is a colorless, odorless non-flammable gas and is the most prominent Greenhouse gas in Earth's atmosphere. It is recycled through the atmosphere by the process photosynthesis, which makes human life possible. Photosynthesis is the process of green plants and other organisms transforming light energy into chemical energy. Light Energy is trapped and used to convert carbon dioxide, water, and other minerals into oxygen and energy rich organic compounds. (Encyclopedia Britannica Volume 25) Carbon Dioxide is emitted into the air as humans exhale, burn fossil fuels for energy, and deforests the planet. Every year humans add over 30 billion tons of carbon dioxide in the atmosphere by these processes, and it is up thirty percent since 1750 (www.envirolink.org/orgs/edf/sitemap.html). An isolated test at Mauna Loa in Hawaii revealed more than a 12% (316 ppm in 1959 to 360 ppm in 1996) increase in mean annual concentration of carbon dioxide. Mauna Loa, located in Hawaii, is the world’s largest volcano at 40,000 cubic km and 4,170 meters above sea level. (Encyclopedia Britannica Volume 27) . Ice core samples have also shown a dramatic increase in carbon dioxide levels. Drilling deep into glaciers and polar ice caps and taking out samples of ice, then melting the ice and capturing the gas has shown an increase in carbon dioxide concentrations over the past 100 years. Ice core samples are essentially "drilling through time", because the deeper the ice is, the older the ice is. In 1996, carbon dioxide world emissions increased by 2.8%. The U.S. reported a 3.3% increase in CO2 concentrations. The U.S. continues to emit more than any other country in the world, accounting for 25% of all emissions. The European Union had an increase of 2.2%, much larger than a small increase of 1.1% in 1995. Eastern Europe had a decreasing rate of -2.4%. China's increase in 1996 was 4.7%.(http://infoweb.magi.com/~dwalsh/wfsesr.html) Fossil Fuels were created chiefly by the decay of plants from millions of years ago. We use coal, oil and natural gas to generate electricity, heat our homes, power our factories and run our cars. These fossil fuels contain carbon, and when they are burned, they combine with oxygen, forming carbon dioxide. The two atoms of oxygen add to the total weight. The World Energy Council reported that global carbon dioxide emissions from buring fossil fuels rose 12% between 1990 and 1995. (www.eb.com:180) The increase from developing countries was three times that from developed countries. Middle East carbon dioxide emissions from burning of fossil fuels increased 35%, Africa increased 12%, and Eastern Europe increased rates by 75% from 1990-1995.
This graph shows the increase of carbon dioxide in the air over the past few centuries

Ice Core samples and samples at Mauna Loa, Hawaii, reveal an increase CO2 concentrations
Pie chart shows how CO2 is produced
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Cars also contribute to CO2 in the atmosphere.
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Deforestation is another main producer of carbon dioxide. The causes of deforestation are logging for lumber, pulpwood, and fuel wood. Also contributing to deforestation are clearing new land for farming and pastures used for animals such as cows. Forests and wooded areas are natural carbon sinks. This means that as trees absorb carbon dioxide, and release oxygen, carbon is being put into trees. This process occurs naturally by photosynthesis, which occurs less and less as we cut and burn down trees. As the abundance of trees declines, less carbon dioxide can be recycled. As we burn them down, carbon is released into the air and the carbon bonds with oxygen to form carbon dioxide, adding to the greenhouse effect. About 860 acres, the size of Central Park in New York, is destroyed every 15 minutes in the tropics.
Deforestation and Forest Fires contribute to an increase in CO2 levels
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The Amazon Rain Forest, which is in parts of Brazil, French Guiana, Suriname, Guyana, Venezuela, Nicaragua, Costa Rica, Panama, Columbia, Ecuador, Peru, and Bolivia, is subjected to a great deal of deforestation
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Methane
Methane is a colorless, odorless, flammable gas. It is formed when plants decay and where there is very little air. It is often called swamp gas because it is abundant around water and swamps. Bacteria that breakdown organic matter in wetlands and bacteria that are found in cows, sheep, goats, buffalo, termites, and camels produce methane naturally. Since 1750, methane has doubled, and could double again by 2050. Each year we add 350-500 million tons of methane to the air by raising livestock, coal mining, drilling for oil and natural gas, rice cultivation, and garbage sitting in landfills.(www.envirolink.org/orgs/edf/sitemap.html) It stays in the atmosphere for only 10 years, but traps 20 times more heat than carbon dioxide.
Methane is on the rise since 1750
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Rice cultivation has developed into a large business; farmland has doubled in the past 45 years.(www.envirolink.org/orgs/edf/sitemap.html) It feeds 1/3 of the World's population. It grows mostly in flooded fields, where bacteria in waterlogged soil releases methane.
Livestock such as cows, sheep, goats, camels, buffaloes, and termites release methane as well. Bacteria in the gut of the animal break down food and convert some of it to methane. When these animals belch, methane is released. In one day, a cow can emit ½ pound of methane into the air. Imagine 1.3 billion cattle each burping methane several times per minute!
Cows such as these contribute a large amount of methane to the air.
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Nitrous Oxide
Nitrous oxide is another colorless greenhouse gas, however, it has a sweet odor . It is primarily used as an anesthetic because it deadens pain and for this characteristic is called ?laughing gas.? This gas is released naturally from oceans and by bacteria in soils. Nitrous oxide gas risen by more than 15% since 1750. Each year we add 7-13 million tons into the atmosphere by using nitrogen based fertilizers, disposing of human and animal waste in sewage treatment plants, automobile exhaust, and other sources not yet identified. It is important to reduce emissions because the nitrous oxide we release today will still be trapped in the atmosphere 100 years from now. (World Book Volume 13)
Nitrous Oxide has been on the rise since 1750
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Nitrogen based fertilizer use has doubled in the past 15 years. These fertilizers provide nutrients for crops; however, when they breakdown in the soil, nitrous oxide is released into the atmosphere. In automobiles, nitrous oxide is released at a much lower rate than carbon dioxide, because there is more carbon in gasoline than nitrogen.
Fluorocarbons
Fluorocarbons is a general term for any group of synthetic organic compounds that contain fluorine and carbon. Many of these compounds, such as chlorofluorocarbons(CFC?s), can be easily converted from gas to liquid or liquid to gas. Because of these properties, CFC?s can be used in aerosol cans, refrigerators, and air conditioners. Studies in the 1970?s showed that when CFC?s are emitted into the atmosphere, they break down molecules in the Earth's ozone layer (World Book). Since then, the use of CFC?s has significantly decreased and they are banned from production in the United States. The substitute for CFC?s are hydrofluorocarbons (HFC's). HFC?s do not harm or breakdown the ozone molecule, but they do trap heat in the atmosphere, making it a greenhouse gas, aiding in global warming. HFC?s are used in air conditioners and refrigerators. The way to reduce emissions of this gas is to be sure that in both devices the coolant is recycled and all leaks are properly fixed . Also, before throwing the appliances away, be sure to recover the coolant in each.
Refrigerators and Air Conditioners using CFC's were a huge problem for the ozone layer, but now HFC's are a problem for the climate.
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Global Warming is Here
Naturally, if there are more greenhouse gases in the atmosphere, this greenhouse effect will be more significant and raise the temperature of Earth more than if humans didn't emit as much greenhouse gases. Peter Tans, a physicist with National Oceanic and Atmospheric Administrations (NOAA) Climate Monitoring and Diagnostics Lab says, ?There is no doubt that both land and ocean surface temperatures have gone up significantly in the last 100 years or so.? (www.abcnew.com/sections/us/global106.html) This statement supports the trend of global warming, but does not acknowledge the source. The director of NOAA?s Geophysical Fluid Dynamics Lab at Princeton, Jerry Malhan, says, ?The Earths surface temperature has warmed about one degree Fahrenheit in the last 100 years, and there is no credible hypothesis for this, other than the net effect of greenhouse gases." (www.abcnews.com/sections/us/global106.index.html) Jerry Malhan offers a quote supporting the theory of global warming and also states that it is directly related to the increase of greenhouse gases. ?The planet is heating up and the evidence suggests that human activities are having a significant impact,? Jane Lubchenco said. (www.abcnews.com/sections/us/global106/index.html) Jane was the past President of the American Association for the Advancement of Science, who briefed President Clinton on global warming in July, 1997. The world's leading authority on global warming, the Intergovernmental Panel on Climate Change (IPCC), is a United Nations sponsored organization made up of 2500 scientists from around the world. They have concluded by consensus that "The balance of evidence suggests a discernible human influence on global climate." They project that global warming will have severe impacts on human health, natural ecosystems, agriculture, and coastal communities. (www.toowarm.org./factsheets/basfact.html) This evidence supports the common belief that Global Warming is occurring due to the increased concentration of greenhouse gases in the atmosphere, carbon dioxide, nitrous oxide, methane, and HFC?s.

Average yearly temperature rise: 1860-1998
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Effects of Global Warming on Environment
There are many environmental problems coming from the increase concentration of greenhouse gases in Earth's atmosphere. As Jeff Rubin of ABC NEWS reported, ?Several signs indicate that we've begun changing Earth's climate: increased water vapor in the atmosphere, glaciers and polar ice caps appear to be melting, floods and droughts are becoming more severe, and sea levels have risen, on average, between 4 and 10 inches since 1990.? (www.abc.com/sections/us/global106.html) Experts concur, ?We are already beginning to see this (global warming) taking place - a lot more flooding, a lot more droughts,? Jane Lubchenco said. Jerry Malham added, ?By 2100, we might get a 2 foot sea level rise, but the catch is, levels might continue to rise 2 or 3 feet per century, for 1000 years.?(www.abcnews.com/sections/us/global106.html) These rises in sea level can increase the salinity of freshwater throughout the world, and cause coastal lands to be washed under the ocean. Warmer water and increased humidity may encourage tropical cyclones, and changing wave patterns could produce more tidal waves and strong beach erosion on the coasts.
Flooding form global warming may be already happening.
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Picture of a typhoon from space
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The effects of droughts on crops
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Effects of Global Warming on Society
Agriculturally, Dr. Sylvan H. Wittwer believes that global warming is good for the human race, because it helps increase food production. "The most determinant factor in agriculture production is climate. History reveals that for food production, warming is better than cooling." Dr. Wittwer says that carbon dioxide is an essential nutrient for the production of food, and food is one of the most important things in our lives. As the temperature rises, more farmland will be open towards the poles and the length of the growing season will also lengthen. With all the people who go hungry each day, Dr. Wittwer believes food production should be one of our main concerns. Dr. Wittwer is the scientific pioneer who conducted the original studies on atmospheric CO2 enhancement of the production of food crops.(www.comnett.net/~wit/food.html)
Increasing amounts of greenhouse gases in the atmosphere and global warming could also lead to more health concerns. A statement released from the Intergovernmental Panel on Climate Change (IPCC) said, "Climate change is likely to have wide-ranging and mostly adverse impacts on human health, with significant loss of life." As temperatures increase towards the poles, similar to farmland, insects and other pests migrate towards Earth's poles. These insects and pests could be allowed to migrate up to 550 Km or 550 miles. Some insects carry diseases such as malaria and dengue fever. Thus, an increase in these particular insects and pests closer to the poles results in an increase in these diseases. This could lead to 50 to 80 million additional cases of Malaria annually, a 10-15% increase. "Malaria and dengue fever are already beginning to spread pole wards", said Jane Lubchenco, past president of American Association for the advancement of science. (www.epa.gov/oppeoeel/globalwarming/impacts/health/index.html) Physician Paul Epstein, of Harvard's School of Public Health, says "Climate change is already a factor in terms of the distributions of malaria, dengue fever, and cholera." (www.aloha.net~jhanson/page70.htm) The most obvious health effect is directly from the heat itself. With an increase in heat waves, there will be more people who will suffer from heatstroke, heart attacks and other ailments aggravated by the heat. According to the EPA, "In July 1995, a heat wave killed more than 700 people in the Chicago area alone." (www.epa.gov/oppeoeel/globalwarming/impacts/health/index.html) If this is happening already from heat, imagine what would occur in the future with global warming. Hot conditions could also cause smoke particles and noxious gases to linger in the air and accelerate chemical reactions that generate other pollutants. (www.envirolink.org/orgs/edf/sitemap.html) This leads to an increase in risk of respiratory diseases like bronchitis and asthma.
Global warming causes the oceans to warm and expand, inducing a rise in sea level. Eventually, the rising waters could take away land inhabited by people, forcing them to move. Dr. Robert Buddemieir, of the Kansas Geological Survey said, "Bangledesh is massively populated, achingly poor, and something like a sixth of the country is going to go away" (www.envirolink.org/orgs/edf/sitemap.html) Bangladesh cannot afford to build barriers to hold back the sea, so people would have to move inland, increasing the populations density and leading to an increase in hunger and disease. (www.envirolink.org/orgs/edf/sitemap.html) The Maldive Islands in the Indian Ocean have the same problem They are a nation of 1190 islands with an average height of about 1.5 meters above sea level. If the sea level rises, more than 200,000 people will have to abandon their homes. (www.envirolink.org/orgs/edf/sitmap.html) Warming of the oceans could also promote toxic algae which can lead to cholera.

Graph showing history of sea level and extrapolating possible increases in sea level over the next century
The blue line represents the history of sea level. The yellow line is a high estimate of sea level extrapolated. The red line a central estimate, and the green line is a low projection.
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The Present ways of Producing Energy
This pie graph shows the breakdown of how the world produces its energy
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Fossil fuels, chiefly coal, oil and natural gas, now supply most of the world's energy. Only a small amount comes from renewable sources , which do not release gases that trap heat in the atmosphere. If we could get more of our energy from renewable sources, we could reduce the amount of fossil fuels we burn. By the year 2050, renewable sources could provide forty percent of the energy needed in the world. Use of renewable energy can help both to slow global warming and to reduce air pollution. (www.doc.mmu.ac.uk/aric/gcc/cell.html#pos6)
These fossil fuels, coal, oil, and natural gas also emit greenhouse gases when burned. Coal emits high amounts of greenhouse gases, and the world may be supplied with enough of it to last over 100 years. Oil emits high amounts of greenhouse gases and also other types of air pollution harmful to the environment. The world's oil supply is also estimated to last over 100 years. Natural Gas is the lowest of all fossil fuels in greenhouse gas emissions; supplies are projected to last over 100 years. (www.doc.mmu.ac.uk/aric/gcc/cell.html#pos6)
1996 Processes Carbon Dioxide was Produced
Country (region)
OIL
Natural Gas
Coal
World
44.7%
18.4%
36.9%
Canada
51.8%
30%
18.2%
United States
45%
21.3%
33.7%
European Union
56.2%
19%
24.8%
China
17.4%
1.1%
81.5%
Japan
64.6%
9.9%
25.5%
This chart shows what percentage of CO2 comes from Oil, Natural Gas, and Coal. For example, in 1996, 44.7% of the world's CO2 emissions came from the combustion of oil.
http://infoweb.magi.com/~dwalsh/wfsesr.html
This chart shows how much coal different areas of the world have produced and consumed over time


Coal accounts for 24% of the worlds energy; Natural gas 18%
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Solutions for Producing "Cleaner"Energy
Hydro power, currently supplying only six percent of the world's energy, is a renewable energy source. Energy is produced by hydraulic turbines that rotate with the force of rushing water (higher to lower elevation). It is one of the most clean and cheapest way of producing energy, but it can also change the flow of rivers and increase sediment which kills fish. It is a large investment for developing countries. (www.abcnews.com/sections/us/global106)
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Hydro Power plant on a river
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Denmark is currently the world leader in wind power. By 2030, fifty percent of Denmark's energy could be produced by wind power. Randall Swisher, executive director of the American WInd Energy Association says, "If this country made an aggressive development push, by 2020 eighteen percent of the country's energy could be supplied by wind power." (www.abc.com/sections/us/global106.html) Wind power emits no greenhouse gases, but it takes up large amounts of land. In order for it to be a reliable source, scientists must develop better power storage techniques. Another concern of people is noise pollution that the large windmills produce along with the reliability of wind.

A field of wind mills
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Solar power uses photovoltaic cells (PV's) to gather thermal energy directly from the sun and use it to produce electricity. One community could be supplied by one field of PV's . Passive solar cells could also be used to heat water, replacing the need for today's hot water heaters. PV's do not emit any greenhouse gases, but they are very expensive and more development is needed in order for this to be realistic energy source for the future. (www.abcnews.com/sections/us/global106.html)



A field of PV's gathering sunlight to produce power
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Nuclear power is strong is Europe with about forty-two percent of their energy produced by fission. Nuclear generation provides about 17% of world electricity, avoiding the emission of up to 2.3 billion tonnes of carbon dioxide annually. France produces 76% and Lithuania produces 85.6% of its energy by nuclear fission.(http://infoweb.magi.com/~dwalsh/wfsesr.html) In the United States, people are antinuclear because of 3 Mile Island in 1979 and Chernobyl in 1986. However, many experts say that it is a safe, clean, and reliable source of energy. Nuclear Fission produces no greenhouse gases, but does produce highly toxic radioactive wastes.
Nuclear power plants have had success in Europe, but not in the United States
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Kyoto Protocol
One of the major conventions concerning global warming resulted in the Kyoto Protocol, held in Kyoto, Japan, between December 1-11, 1997. Delegates from all over the world were present in order to find a universal agreement to reduce greenhouse gas emissions. The results had most developed nations doing most of the reducing; the United States must cut emissions 7%, Japan 6%, and the European Union 8% below 1990 levels. (www.state.gov/global/oes/fs_kyoto_climate_980115.html)
The United States proposed a plan to have these levels cut over a five year period between 2008-2013. The United States also said it will not sign the protocol if other developing/undeveloped countries do not sign it as well, fearing the economy will falter. The U.S. was successful in emissions trading with other countries who have less emissions. This means that the U.S. or other developed countries can purchase emission permits from other countries who have extra permits. This stresses the importance of flexibility the U.S. was looking for when it said it cannot lower the emission levels until at least 2008. Again, the U.S. is trying to look out for it's own economy first. If a country shall fail in completing its goal, the country will then not be able to receive joint implementation projects. However, this Protocol is not yet law; it must be ratified by at least 55 countries, accounting for 55% of the world's total greenhouse gas emissions.. It can be signed by countries starting in March of 1998. The next convention is in November 1998, in Buenos Aires. (www.state.gov/global/oes/fs_kyoto_climate_980115.html)
If the Kyoto Protocol becomes the law of the land, there are potential economic problems that may lead to a change in quality of life for many Americans. By reducing greenhouse gas emissions, people will be more healthy due to better air quality and water quality. However, there may be a reduction in the rate of economic development because industries will have to adapt and find different ways of producing goods. People will have to drive smaller, lighter cars, ride bicycles more often, and increase efficiency in many ways.
Opinion
The world's leading scientists project that during our children's lifetimes global warming will raise the average temperature of the planet by 2 to 6 degrees Fahrenheit, or 1-3.5 degree Celsius. In contrast the Earth is only 5 to 9 degrees Fahrenheit or about 3-6 degrees Celsius warmer today than it was 10,000 years ago during the last ice age. Man-made global warming is occurring much faster than at any other time in at least the last 10,000 years. (www.toowarm.org/factsheets/basfact.html#How) This information would suggest that the warming Earth is experiencing now is not a natural phenomenon, but caused by the increased concentration of greenhouse gases. While evidence is strong to support the notion of human contribution to the global warming problem, an alternative view is that recent global warming is a natural occurrence. Some theorists believe that the Earth's climate works in a cycle, cooling, and then warming itself. Scientists point out the fact that 75 million years ago, the Earth's average temperature was ten degrees higher than it is today. Conditions were warmer and more humid, but life sustained. (www.enviolink.org/orgs/edf/sitemap.html) Another phenomenon to take into account is the "little ice age", which occurred from 1550-1850 A.D. Conditions around the world were cooler than usual; many bodies of water froze over. The average global temperature since the little ice age has risen by one degree Fahrenheit! Shouldn't it be expected that after that ice age was over that the temperature on Earth would rise at least one degree? The bottom line is that it may seem that only human actions are causing global warming, but it is very possible that global warming is nothing to worry about and is just part of the global temperature cycle. Both theories are credible, but neither has yet been proven.
Terms
1. Carbon Dioxide - a heavy colorless gas that does not support combustion, dissolves in water to form carbonic acid, is formed especialy in animal repiration and in the decay or combustion of animal and vegetable matter, is absorbed from the air by plants in photosynthesis, and is used in the carbonation of beverages.
2. Methane- a colorless odorless flammable gaseous hydrocarbon that is a product of decompositions of organic matter and of the carbonization of coal, is used as a fuel and as a starting material in chemical synthesis, and is the simplest of the alkanes.
3. Photosynthesis- synthesis of chemical compounds with the aid of radiant energy and especially light; especially formation of carbohydrates from carbon dioxide and a source of hydrogen in the chlorophyll-containing tissues of plants exposed to light
4. Greenhouse Effect- warming of the surface and lower atmosphere of a planet that is caused by conversion of solar radiation into heat in a process involving selective transmission of short wave solar radiation by the atosphere, its absorption by the planet's surface, and reradiation as infared which is absorbed and partly reradiated back to the surface by atmospheric gases.
5. Nitrous oxide - a colorless gas that when inhaled produces loss of sensibility to pain preceded by exhilaration and sometimes laughter and is used as an anesthetic in dentistry and that is an atmospheric pollutant produced by combustion and a suspected contributor to greenhouse warming -- also called laughing gas.
6. Malaria - a human disease that is caused by sporazoan parasites in the red blood cells, is transmitted by the bite of anopheline mosquitoes, and is characterized by peo\riodic attacks of chills and fever
7. Dengue - an acute infectious disease caused by an arbovirus, transmitted by aedes mosquitoes, and characterized by headache, severe joint pain, and a rash--called also dengue fever.