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Transcript of 2AM SEMINAR WORK
PAPER ON THE EFFECT OF GREEN HOUSE GASES ON THE ENVIRONMENT
BY ARIERE ARODOVWE MARVELOUS (1101/2012)EARTH SCIENCE DEPARTMENT (GEOLOGY OPTION) JUNE, 2016
AbstractThe amount of solar energy absorbed or radiated by Earth is modulated by the atmosphere and depends on its composition. Greenhouse gases - such as water vapor, carbon dioxide, and methane - occur naturally in small amounts and absorb and release heat energy more efficiently than abundant atmospheric gases like nitrogen and oxygen. Small increases in carbon dioxide concentration have a large effect on the climate system. The existence of a heavier layer of greenhouse effect gases at the level of the entire planet triggers significant climate changes. This paper intends to present the main environmental indicators elaborated by various specialized international bodies, and the models used by different governmental or non-governmental bodies for studying the impact/effects of greenhouse effect gas emissions on the environment, climatic changes or economic development.
TABLE OF CONTENT
Executive Summary........................................................................................................................1
Introduction.....................................................................................................................................1
Understanding Green House Effect.................................................................................................1
Looking Forward.............................................................................................................................1
Table of Content ………………………………………………………………………………….1
ABSTRACT…………………………………………………………………………….
INTRODUCTION……………………………………………………………………...3
What are Greenhouse Gases……………………………………………………………..3
Sources of Greenhouse Gases…………………………………………………………...5
Types of Greenhouse Gases…...………………………………………………………...6
What is the Greenhouse Effect………………………………………………………….7
UNDERSTANDING THE GREEN HOUSE EFFECT……………………………....9
What causes the Greenhouse Effect………..………………………………………….....9
How do humans contribute to the Greenhouse Effect……..…………………………….10
Scientific issues surrounding the Greenhouse Effect……….………………………..….11
Consequences of enhanced Greenhouse effect…..……………………………….....…..16
LOOKING FORWARD (MITIGATION TO THE GREEN HOUSE EFFECT)…22
The Industrial Sector……………………………………………………………………23
The Transportation Sector………………………………………………………………23
Renewables…………………………………………………………………………….24
Forestry and Agriculture………………………………………………………………25
Information……………………………………………………………………………25
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CONCLUSION…………………………………………………..……………………….27
REFERENCES……………………………………………………………………………28
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INTRODUCTION
The Sun powers Earth’s climate, radiating energy at very short wavelengths, predominately in
the visible or near-visible (e.g., ultraviolet) part of the spectrum. Roughly one-third of the solar
energy that reaches the top of Earth’s atmosphere is reflected directly back to space. The
remaining two-thirds is absorbed by the surface and, to a lesser extent, by the atmosphere. To
balance the absorbed incoming energy, the Earth must, on average, radiate the same amount of
energy back to space. Because the Earth is much colder than the Sun, it radiates at much longer
wavelengths, primarily in the infrared part of the spectrum. Much of this thermal radiation
emitted by the land and ocean is absorbed by the atmosphere, including clouds, and reradiated
back to Earth. This is called the greenhouse effect. The glass walls in a greenhouse reduce
airflow and increase the temperature of the air inside. Analogously, but through a different
physical process, the Earth’s greenhouse effect warms the surface of the planet. Without the
natural greenhouse effect, the average temperature at Earth’s surface would be below the
freezing point of water. Thus, Earth’s natural greenhouse effect makes life as we know it pos-
sible. However, human activities, primarily the burning of fossil fuels and clearing of forests,
have greatly intensified the natural greenhouse effect, causing global warming.
What are greenhouse gases?
Greenhouse gases include methane, chlorofluorocarbons and carbon dioxide. These gases act as
a shield that traps heat in the earth’s atmosphere. A greenhouse gas is any gaseous compound in the atmosphere that is capable of absorbing infrared radiation, thereby trapping and holding heat in the atmosphere. By increasing the heat in the atmosphere, greenhouse gases are responsible for the greenhouse effect, which ultimately leads to global warming.
The two most abundant gases in the atmosphere, nitrogen (comprising 78% of the dry
atmosphere) and oxygen (comprising 21%), exert almost no greenhouse effect. Instead, the
greenhouse effect comes from molecules that are more complex and much less common. Water
vapour is the most important greenhouse gas, and carbon dioxide (CO2) is the second-most
important one. Methane, nitrous oxide, ozone and several other gases present in the atmosphere
in small amounts also contribute to the greenhouse effect. In the humid equatorial regions, where
there is so much water vapour in the air that the greenhouse effect is very large, adding a small
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additional amount of CO2 or water vapour has only a small direct impact on downward infrared
radiation. However, in the cold, dry polar regions, the effect of a small increase in CO2 or water
vapour is much greater. The same is true for the cold, dry upper atmosphere where a small
increase in water vapour has a greater influence on the greenhouse effect than the same change in
water vapour would have near the surface.
Several components of the climate system, notably the oceans and living things, affect
atmospheric concentrations of greenhouse gases. A prime example of this is plants taking CO2
out of the atmosphere and converting it (and water) into carbohydrates via photosynthesis. In the
industrial era, human activities have added greenhouse gases to the atmosphere, primarily
through the burning of fossil fuels and clearing of forests. Adding more of a greenhouse gas,
such as CO2, to the atmosphere intensifies the greenhouse effect, thus warming Earth’s climate.
The amount of warming depends on various feedback mechanisms. For example, as the
atmosphere warms due to rising levels of greenhouse gases, its concentration of water vapour
increases, further intensifying the greenhouse effect. This in turn causes more warming, which
causes an additional increase in water vapour, in a self-reinforcing cycle. This water vapour feed-
back may be strong enough to approximately double the increase in the greenhouse effect due to
the added CO2 alone.
Additional important feedback mechanisms involve clouds. Clouds are effective at absorbing
infrared radiation and therefore exert a large greenhouse effect, thus warming the Earth. Clouds
are also effective at reflecting away incoming solar radiation, thus cooling the Earth. A change in
almost any aspect of clouds, such as their type, location, water content, cloud altitude, particle
size and shape, or lifetimes, affects the degree to which clouds warm or cool the Earth. Some
changes amplify warming while others diminish it. Much research is in progress to better
understand how clouds change in response to climate warming, and how these changes affect
climate through various feedback mechanisms.
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Sources of greenhouse gases
Some greenhouse gases, like methane, are produced through agricultural practices including
livestock manure management. Others, like CO2, largely result from natural processes like
respiration and from the burning of fossil fuels like coal, oil and gas. The production of
electricity is the source of 70 percent of the United States' sulfur dioxide emissions, 13 percent of
nitrogen oxide emissions, and 40 percent of carbon dioxide emissions, according to the EPA.
The second cause of CO2 release is deforestation, according to research published by Duke
University. When trees are killed to produce goods or heat, they release the carbon that is
normally stored for photosynthesis. This process releases nearly a billion tons of carbon into the
atmosphere per year, according to the 2010 Global Forest Resources Assessment.
It's worth noting that forestry and other land-use practices offset some of these greenhouse gas
emissions, according to the EPA. "Replanting helps to reduce the buildup of carbon dioxide in
the atmosphere as growing trees sequester carbon dioxide through photosynthesis. Atmospheric
carbon dioxide is converted and stored in the vegetation and soils of the forest. However, forests
cannot sequester all of the carbon dioxide we are emitting to the atmosphere through the burning
of fossil fuels and a reduction in fossil fuel emissions is still necessary to avoid build up in the
atmosphere," said Daley.
Worldwide, the output of greenhouse gases is a source of grave concern: From the time the
Industrial Revolution began to the year 2009, atmospheric CO2 levels have increased almost 38
percent and methane levels have increased a whopping 148 percent, according to NASA, and
most of that increase has been in the past 50 years. Because of global warming, 2014 was the
warmest year on record and 10 of the hottest years have all come after 1998.
"The warming we observe affects atmospheric circulation, which impacts rainfall patterns
globally. This will lead to big environmental changes, and challenges, for people all across the
globe," Josef Werne, an associate professor in the department of geology and planetary science
at the University of Pittsburgh, told Live Science.
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If these trends continue, scientists, government officials and a growing number of citizens fear
that the worst effects of global warming — extreme weather, rising sea levels, plant and animal
extinctions, ocean acidification, major shifts in climate and unprecedented social upheaval —
will be inevitable. In answer to the problems caused by global warming by greenhouse gasses,
the government created a climate action plan in 2013.
Types of Greenhouse gases
Greenhouse gases comprise less than 1% of the atmosphere. Their levels are determined by a
balance between “sources” and “sinks”. Sources and sinks are processes that generate and
destroy greenhouse gases respectively. Human affect greenhouse gas levels by introducing new
sources or by interfering with natural sinks. The major greenhouse gases in the atmosphere are
carbon dioxide (CO2), methane, (CH4), nitrous oxide (N2O), chlorofluorocarbons (CFCs) and
ozone (O3). Atmospheric water vapour (H2O) also makes a large contribution to the natural
greenhouse effect but it is thought that its presence is not directly affected by human activity.
Characteristics of some of the greenhouse gases are shown in Table 1 below
Plate 1: Major Green House Gases and Their Percentages
Source: Encarta Encyclopedia
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Table 1: Characteristics of some major greenhouse gases
What is the Greenhouse Effect?
The “Greenhouse Effect” is a term that refers to a physical property of the Earth's atmosphere. If
the Earth had no atmosphere, its average surface temperature would be very low of about 18℃ rather than the comfortable 15℃ found today. The difference in temperature is due to a suite of
gases called greenhouse gases which affect the overall energy balance of the Earth's system by
absorbing infrared radiation. In its existing state, the Earth atmosphere system balances
absorption of solar radiation by emission of infrared radiation to space. Due to greenhouse gases,
the atmosphere absorbs more infrared energy than it reradiates to space, resulting in a net
warming of the Earth atmosphere system and of surface temperature. This is the “Natural
Greenhouse Effect”. With more greenhouse gases released to the atmosphere due to human
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activity, more infrared radiation will be trapped in the Earth's surface which contributes to the
“Enhanced Greenhouse Effect”.
The greenhouse effect increases the temperature of the Earth by trapping heat in our atmosphere.
This keeps the temperature of the Earth higher than it would be if direct heating by the Sun was
the only source of warming. When sunlight reaches the surface of the Earth, some of it is
absorbed which warms the ground and some bounces back to space as heat. Greenhouse
gases that are in the atmosphere absorb and then redirect some of this heat back towards the
Earth.
The greenhouse effect is a major factor in keeping the Earth warm because it keeps some of the
planet's heat that would otherwise escape from the atmosphere out to space. In fact, without the
greenhouse effect the Earth's average global temperature would be much colder and life on Earth
as we know it would not be possible. The difference between the Earth's actual average
temperature 14° C (57.2° F) and the expected effective temperature just with the Sun's radiation -
19° C (-2.2° F) gives us the strength of the greenhouse effect, which is 33° C
The greenhouse effect is a natural process that is millions of years old. It plays a critical role in
regulating the overall temperature of the Earth. The greenhouse effect was first discovered by
Joseph Fourier in 1827, experimentally verified by John Tyndall in 1861, and quantified by
Svante Arrhenius in 1896.
Plate 2 A simplified diagram illustrating the global long term radiative balance of the atmosphere.
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Source: Encarta Encyclopedia
* Carbon dioxide’s lifetime is poorly defined because the gas is not destroyed over time, but instead moves among different parts of the ocean–atmosphere–land system. Some of the excess carbon dioxide will be absorbed quickly (for example, by the ocean surface), but some will remain in the atmosphere for thousands of years, due in part to the very slow process by which carbon is transferred to ocean sediments.
Table 2: Major Long-Lived Greenhouse Gases and Their Characteristics
UNDERSTANDING THE GREEN HOUSE EFFECT
What Causes the Greenhouse Effect?
Life on earth depends on energy from the sun. About 30 percent of the sunlight that beams
toward Earth is deflected by the outer atmosphere and scattered back into space. The rest reaches
the planet's surface and is reflected upward again as a type of slow-moving energy called
infrared radiation.
The heat caused by infrared radiation is absorbed by greenhouse gases such as water vapor,
carbon dioxide, ozone and methane, which slows its escape from the atmosphere.
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Although greenhouse gases make up only about 1 percent of the Earth's atmosphere, they
regulate our climate by trapping heat and holding it in a kind of warm-air blanket that surrounds
the planet.
This phenomenon is what scientists call the greenhouse effect. Without it, scientists estimate that
the average temperature on Earth would be colder by approximately 30 degrees Celsius (54
degrees Fahrenheit), far too cold to sustain most of our current ecosystems.
How Do Humans Contribute to the Greenhouse Effect?
While the greenhouse effect is an essential environmental prerequisite for life on Earth, there
really can be too much of a good thing.
The problems begin when human activities distort and accelerate the natural process by
creating more greenhouse gases in the atmosphere than are necessary to warm the planet to an
ideal temperature.
Burning natural gas, coal and oil, including gasoline for automobile engines, raises the level of
carbon dioxide in the atmosphere.
Some farming practices and other land uses increase the levels of methane and nitrous oxide.
Many factories produce long-lasting industrial gases that do not occur naturally, yet
contribute significantly to the enhanced greenhouse effect and global warming that is currently
under way.
Deforestation also contributes to global warming. Trees use carbon dioxide and give off oxygen
in its place, which helps to create the optimal balance of gases in the atmosphere. As more
forests are logged for timber or cut down to make way for farming, however, there are fewer
trees to perform this critical function. At least some of the damage can be offset when young
forests aggressively regrow, capturing tons of carbon.
Population growth is another factor in global warming, because as more people use fossil fuels
for heat, transportation and manufacturing the level of greenhouse gases continues to increase.
As more farming occurs to feed millions of new people, more greenhouse gases enter the
atmosphere.
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Ultimately, more greenhouse gases means more infrared radiation trapped and held, which
gradually increases the temperature of the Earth's surface, the air in the lower atmosphere,and
ocean waters.
Scientific Issues Surrounding the Greenhouse Effect
It is helpful to break down the set of issues known as the greenhouse effect into a series of
stages, each feeding into another, and then to consider how policy questions might be addressed
in the context of these more technical stages.
Projecting emissions. Behavioral assumptions must be made in order to project future use of
fossil fuels (or deforestation, because this too can impact the amount of CO2 in the atmosphere--
it accounts for about 20% of the recent total CO2 injection of about 5.5 x 10 9 metric tons). The
essence of this aspect then is social science. Projections must be made of human population, the
per capita consumption of fossil fuel, deforestation rates, reforestation activities, and perhaps
even countermeasures to deal with the extra CO2 in the air. These projections depend on issues
such as the likelihood that alternative energy systems or conservation measures will be available,
their price, and their social acceptability. Furthermore, trade in fuel carbon (for example, a large-
scale transfer from coal-rich to coal-poor nations) will depend not only on the energy
requirements and the available alternatives but also on the economic health of the potential
importing nations. This trade in turn will depend upon whether those nations have adequate
capital resources to spend on energy rather than other precious strategic commodities--such as
food or fertilizer as well as some other strategic materials such as weaponry. Total CO2
emissions from energy systems, for example, can be expressed by a formula termed "the
population multiplier" by Ehrlich and Holdren
The first term represents engineering effects, the second standard of living, and the third
demography in this version, which is expanded from the original.
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In order to quantify future changes, we can make scenarios that show alternative CO 2 futures
based on assumed rates of growth in the use of fossil fuels. Most typical projections are in the 0.5
to 2% annual growth range for fossil fuel use and imply that CO2 concentrations will double (to
600 ppm) in the 21st century. There is virtually no dispute among scientists that the CO2
concentration in the atmosphere has already increased by @25% since @1850. The record at
Mauna Loa observatory shows that concentrations have increased from about 310 to more than
350 ppm since 1958. Superimposed on this trend is a large annual cycle in which CO2 reaches a
maximum in the spring of each year in the Northern Hemisphere and a minimum in the fall. The
fall minimum is generally thought to result from growth of the seasonal biosphere in the
Northern Hemisphere summer whereby photosynthesis increases faster than respiration and
atmospheric CO2 levels are reduced. After September, the reverse occurs and respiration
proceeds at a faster rate than photosynthesis and CO2 levels increase. Analyses of trapped air in
several ice cores suggest that during the past several thousand years of the present interglacial,
CO2 levels have been reasonably close to the pre-industrial value of 280 ppm. However, since
about 1850, CO2 has risen @25%. At the maximum of the last Ice Age 18,000 years ago, CO2
levels were roughly 25% lower than pre industrial values. The data also reveal a close
correspondence between the inferred temperature at Antarctica and the measured CO2
concentration from gas bubbles trapped in ancient ice. However, whether the CO2 level was a
response to or caused the temperature changes is debated: CO2 may have simply served as an
amplifier or positive feedback mechanism for climate change--that is, less CO2, colder
temperatures. This uncertainty arises because the specific bio geophysical mechanisms that cause
CO2 to change in step with the climate are not yet elucidated. Methane concentrations in bubbles
in ice cores also show a similar close relation with climate during the past 150,000 years.
Other greenhouse gases like chlorofluorocarbons (CFCs), CH4, nitrogen oxides, tropospheric
ozone, and others could, together, be as important as CO2 in augmenting the greenhouse effect,
but some of these depend on human behavior and have complicated biogeochemical interactions.
These complications account for the large error bars. Space does not permit a proper treatment of
individual aspects of each non-CO2 trace greenhouse gas; therefore, I reluctantly will consider all
greenhouse gases taken together as "equivalent CO2. However, this assumption implies that
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projections for "CO2" alone will be an underestimate of the total greenhouse gas buildup by
roughly a factor of 2. Furthermore, this assumption forces us to ignore possible relations between
CH4 and water vapor in the stratosphere, for example, which might affect polar stratospheric
clouds, which are believed to enhance photochemical destruction of ozone by chlorine atoms.
Projecting greenhouse gas concentrations. Once a plausible set of scenarios for how much CO2
will be injected into the atmosphere is obtained the interacting biogeochemical processes that
control the global distribution and stocks of the carbon need to be determined. Such processes
involve the uptake of CO2 by green plants (because CO2 is the basis of photosynthesis, more CO2
in the air means faster rates of photosynthesis), changes in the amount of forested area and
vegetation type, and how CO2 fertilization or climate change affects natural ecosystems on land
and in the oceans. The transition from ice age to interglacial climates provides a concrete
example of how large natural climatic change affected natural ecosystems in North America.
This transition represented some 5deg.C global warming, with as much as 10deg. to 20deg.C
warming locally near ice sheets. The boreal species now in Canada were hugging the rim of the
great Lauren tide glacier in the U.S. Northeast some 10,000 years ago, while now abundant
hardwood species were restricted to small refuges largely in the South. The natural rate of forest
movement that can be inferred is, to order of magnitude, some @1 km per year, in response to
temperature changes averaging @1deg. to 2deg.C per thousand years. If climate were to change
much more rapidly than this, then the forests would likely not be in equilibrium with the climate;
that is, they could not keep up with the fast change and would go through a period of transient
adjustment in which many hard-to-predict changes in species distribution, productivity, and CO2
absorptive capacity would likely occur.
Furthermore, because the slow removal of CO2 from the atmosphere is largely accomplished
through biological and chemical processes in the oceans and decades to centuries are needed for
equilibration after a large perturbation, the rates at which climate change modifies mixing
processes in the ocean (and thus the CO2 residence time) also needs to be taken into account.
There is considerable uncertainty about how much newly injected CO2 will remain in the air
during the next century, but typical estimates put this so-called "airborne fraction" at about 50%.
Reducing CO2 emissions could initially provide a bonus by allowing the reduction of the
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airborne fraction, whereas increasing CO2 emissions could increase the airborne fraction and
exacerbate the greenhouse effect. However, this bonus might last only a decade or so, which is
the time it takes for the upper mixed layer of the oceans to mix with deep ocean water.
Biological feedbacks can also influence the amount of CO2 in the air. For example, enhanced
photosynthesis could reduce the buildup rate of CO2 relative to that projected with carbon cycle
models that do not include such an effect. On the other hand, although there is about as much
carbon stored in the forests as there is in the atmosphere, there is about twice as much carbon
stored in the soils in the form of dead organic matter. This carbon is slowly decomposed by soil
microbes back to CO2 and other gases. Because the rate of this decomposition depends on
temperature, global warming from increased greenhouse gases could cause enhanced rates of
microbial decomposition of neuromas (dead organic matter), thereby causing a positive feedback
that would enhance CO2 buildup. Furthermore, considerable methane is trapped below frozen
sediments as clathrates in tundra and off continental shelves. These clathrates could release vast
quantities of methane into the atmosphere if substantial Arctic warming were to take place.
Already the ice core data have shown that not only has CO2 tracked temperature closely for the
past 150,000 years, but so has methane, and methane is a significant trace greenhouse gas which
is some 20 to 30 times more effective per molecule at absorbing infrared radiation than CO2.
Despite these uncertainties, many workers have projected that CO2 concentrations will reach 600
ppm sometime between 2030 and 2080 and that some of the other trace greenhouse gases will
continue to rise at even faster rates.
Estimating global climatic response. Once we have projected how much CO2 (and other trace
greenhouse gases) may be in the air during the next century or so, we have to estimate its
climatic effect. Complications arise because of interactive processes; that is, feedback
mechanisms. For example, if added CO2 were to cause a temperature increase on earth, the
warming would likely decrease the regions of Earth covered by snow and ice and decrease the
global albedo. The initial warming would thus create a darker planet that would absorb more
energy, thereby creating a larger final warming. This scenario is only one of a number of
possible feedback mechanisms. Clouds can change in amount, height, or brightness, for example,
substantially altering the climatic response to CO2. And because feedback processes interact in
the climatic system, estimating global temperature increases accurately is difficult; projections of
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the global equilibrium temperature response to an increase of CO2 from 300 to 600 ppm have
ranged from @1.5deg. to 5.5deg.C. (In the next section the much larger uncertainties
surrounding regional responses will be discussed.) Despite these uncertainties, there is virtually
no debate that continued increases of CO2 will cause global warming.
We cannot directly verify our quantitative predictions of greenhouse warming on the basis of
purely historical events; therefore, we must base our estimates on natural analogs of large
climatic changes and numerical climatic models because the complexity of the real world cannot
be reproduced in laboratory models. In the mathematical models, the known basic physical laws
are applied to the atmosphere, oceans, and ice sheets, and the equations that represent these laws
are solved with the best computers available. Then, we simply change in the computer program
the effective amount of greenhouse gases, repeat our calculation, and compare it to the "control"
calculation for the present Earth. Many such global climatic models (GCMs) have been built
during the past few decades, and the results are in rough agreement that if CO2 were to double
from 300 to 600 ppm, then Earth's surface temperature would eventually warm up somewhere
between 1deg. and 5deg.C; the most recent GCM estimates are from 3.5deg. to 5. 0deg.C. For
comparison, the global average surface temperature (land and ocean) during the Ice Age extreme
18,000 years ago was only about 5deg.C colder than that today. Thus, a global temperature
changes of 1deg. to 2deg.C can have considerable effects. A sustained global increase of more
than 2deg.C above present would be unprecedented in the era of human civilization.
The largest uncertainty in estimating the sensitivity of Earth's surface temperature to a given
increase in radiative forcing arises from the problem of parameterization. Because the equations
that are believed to represent the flows of mass, momentum, and energy in the atmosphere,
oceans, ice fields, and biosphere cannot be solved analytically with any known techniques,
approximation techniques are used in which the equations are discretized with a finite grid that
divides the region of interest into cells that are several hundred kilometers or more on a side.
Clearly, critically important variables, such as clouds, which control the radiation budget of
Earth, do not occur on scales as large as the grid of a general circulation model. Therefore, we
seek to find a parametric representation or parameterization that relates implicitly the effects of
important processes that operate at sub grid-scale but still have effects at the resolution of a
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typical general circulation model. For example, a parameter or proportionality coefficient might
be used that describes the average cloudiness in grid cell in terms of the mean relative humidity
in that cell and some other measures of atmospheric stability. Then, the important task becomes
validating these semi empirical parameterizations because at some scale, all models, no matter
how high resolution, must treat sub grid-scale processes through parameterization.
Projecting regional climatic response. In order to make useful estimates of the effects of
climatic changes, we need to determine the regional distribution of climatic change. Will it be
drier in Iowa in 2010, too hot in India, wetter in Africa, or more humid in New York; will
California be prone to more forest fires or will Venice flood? Unfortunately, reliable prediction
of the time sequence of local and regional responses of variables such as temperature and rainfall
requires climatic models of greater complexity and expense than are currently available. Even
though the models have been used to estimate the responses of these variables, the regional
predictions from state-of-the-art models are not yet reliable.
Although there is considerable experience in examining regional changes, considerable
uncertainty remains over the probability that these predicted regional features will occur. The
principal reasons for the uncertainty are twofold: the crude treatment in climatic models of
biological and hydrological processes and the usual neglect of the effects of the deep oceans. The
deep oceans would respond slowly--on time scales of many decades to centuries--to climatic
warming at the surface, and also act differentially (that is, non-uniformly in space and through
time). Therefore, the oceans, like the forests, would be out of equilibrium with the atmosphere if
greenhouse gases increase as rapidly as typically is projected and if climatic warming were to
occur as fast as 2deg. to 6deg.C during the next century. This typical projection, recall, is 10 to
60 times as fast as the natural average rate of temperature change that occurred from the end of
the last Ice Age to the present warm period (that is, 2deg. to 6deg.C warming in a century from
human activities compared to an average natural warming of 1deg. to 2deg.C per millennium
from the waning of the Ice Age to the establishment of the present interglacial epoch). If the
oceans are out of equilibrium with the atmosphere, then specific regional forecasts will not have
much credibility until fully coupled atmosphere-ocean models are tested and applied. The
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development of such models is a formidable scientific and computational task and is still not
very advanced.
Consequences of Enhanced Greenhouse Effect
i) Global Warming
Increase of greenhouse gases concentration causes a reduction in outgoing infrared radiation,
thus the Earth's climate must change somehow to restore the balance between incoming and
outgoing radiation. This “climatic change” will include a “global warming” of the Earth's surface
and the lower atmosphere as warming up is the simplest way for the climate to get rid of the
extra energy.
However, a small rise in temperature will induce many other changes, for example, cloud cover
and wind patterns. Some of these changes may act to enhance the warming (positive feedbacks),
others to counteract it (negative feedbacks). Using complex climate models, the
"Intergovernmental Panel on Climate Change" in their third assessment report has forecast that
global mean surface temperature will rise by 1.4℃ to 5.8℃ by the end of 2100. This projection
takes into account the effects of aerosols which tend to cool the climate as well as the delaying
effects of the oceans which have a large thermal capacity. However, there are many uncertainties
associated with this projection such as future emission rates of greenhouse gases, climate
feedbacks, and the size of the ocean delay etc.
ii) Sea Level Rise
If global warming takes place, sea level will rise due to two different processes. Firstly, warmer
temperature cause sea level to rise due to the thermal expansion of seawater. Secondly, water
from melting glaciers and the ice sheets of Greenland and the Antarctica would also add water to
the ocean. It is predicted that the Earth's average sea level will rise by 0.09 to 0.88 m between
1990 and 2100.
Potential Impact on the Environment / human life
a) Economic Impact
Over half of the human population lives within 100 kilometers of the sea. Most of this population
lives in urban areas that serve as seaports. Rising temperatures would raise sea levels as well,
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reducing supplies of fresh water as flooding occurs along coastlines worldwide and salt water
reaches inland. A measurable rise in sea level will have a severe economic impact on low lying
coastal areas and islands, for examples, increasing the beach erosion rates along coastlines, rising
sea level displacing fresh groundwater for a substantial distance inland.
b) Agricultural Impact
An increase in atmospheric CO2 enhances the agricultural productivity of land resources because
of its direct beneficial effects on crop growth. Over the long run, however, increasing
concentrations of greenhouse gases warm Earth’s climate and thereby modify the potential extent
and productivity of agriculture. The direct effects of CO2 on plant growth and the indirect effects
of climate change also will modify the potential extent and productivity of Earth’s ecosystems.
Human responses to changing agricultural opportunities will interact with ecosystems, as well.
Experiments have shown that with higher concentrations of CO2, plants can grow bigger and
faster. However, the effect of global warming may affect the atmospheric general circulation and
thus altering the global precipitation pattern as well as changing the soil moisture contents over
various continents. Millions of people also would be affected, especially poor people who live in
precarious locations or depend on the land for a subsistence living. Food production, processing,
and distribution can be affected, as well as national security.
c) Effects on Aquatic systems
The loss of coastal wetlands could certainly reduce fish populations, especially shellfish.
Increased salinity in estuaries could reduce the abundance of freshwater species but could
increase the presence of marine species. However, the full impact on marine species is not
known.
d) Effects on Hydrological Cycle
Global precipitation is likely to increase. However, it is not known how regional rainfall patterns
will change. Some regions may have more rainfall, while others may have less. Furthermore,
higher temperatures would probably increase evaporation. These changes would probably create
new stresses for many water management systems.
e) More mobile species
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Many of the world’s endangered species would become extinct as rising temperatures changed their habitat, and affected the timing of seasonal events. Species are straying from their native habitats at an unprecedented rate: 11 miles (17.6 km) toward the poles per decade. Areas where temperature is increasing the most show the most straying by native organisms. The Cetti's warbler, for example, has moved north over the last two decades by more than 90 miles (150 km).
Plate 3: Credit: Kenneth Lohmann, University of North Carolina at Chapel Hill Plate 4: A Cetti’s warbler
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
f) Hurting polar bearsPolar bear cubs are struggling to swim increasingly long distances in search of stable sea ice,
according to a 2011 study. The rapid loss of sea ice in the Arctic is forcing bears to sometimes
swim up to more than 12 days at a time, the research found. Cubs of adult bears that had to
swim more than 30 miles (48 kilometers) had a 45 percent mortality rate, compared with 18
percent for cubs that had to swim shorter distances.
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Plate 5: Credit: USFWS
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
g) Changing genetics
Even fruit flies are feeling the heat. According to a 2006 study, fruit fly genetic patterns normally
seen at hot latitudes are showing up more frequently at higher latitudes. According to the
research, the gene patterns of Drosophila subobscura, a common fruit fly, are changing so that
populations look about one degree closer in latitude to the equator than they actually are. In other
words, genotypes are shifting so that a fly in the Northern Hemisphere has a genome that looks
more like a fly 75 to 100 miles (120 to 161 kilometers) south.
Plate 6: Credit: Giovanni Cancemi | Shutterstock Plate 7: Fruit flies
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
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h) Changed high season at national parks
When's the busiest time to see the Grand Canyon? The answer has changed over the decades as
spring has started earlier. Peak national park attendance has shifted forward more than four days,
on average, since 1979. Today, the highest number of visitors now swarm the Grand Canyon on
June 24, compared with July 4 in 1979.
Plate 8: Credit: Andrea El-Wailly
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
i) Altered Thoreau's stomping grounds
The writer Henry David Thoreau once lovingly documented nature in and around Concord,
Mass. Reading those diaries today has shown researchers just how much spring has changed in
the last century or so. Compared to the late 1800s, the first flowering dates for 43 of the most
common plant species in the area have moved forward an average of 10 days. Other plants have
simply disappeared, including 15 species of orchids.
Plate 9: Credit: © Houghton Library, President and Fellows of Harvard College
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
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j) High-country changes
Decreased winter snowfall on mountaintops is allowing elk in northern Arizona to forage at higher elevations all winter, contributing to a decline in seasonal plants. Elk have ravaged trees such as maples and aspens, which in turn has led to a decline in songbirds that rely on these trees for habitat.
Plate 10: Credit: Don Becker, USGS
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
k) Altering breeding seasons
As temperatures shift, penguins are shifting their breeding seasons, too. A March 2012 study
found that Gentoo penguins are adapting more quickly to warmer weather, because they aren't as
dependent on sea ice for breeding as other species. It's not just penguins that seem to be
responding to climate change. Animal shelters in the U.S. have reported increasing numbers
of stray cats and kittens attributed to a longer breeding season for the felines.
Plate 11: Credit: Wally Walker, National Science Foundation
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
l) Moving the military northward
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As the Arctic ice opens up, the world turns its attention to the resources below. According to the
U.S. Geological Survey, 30 percent of the world's undiscovered natural gas and 13 percent of its
undiscovered oil are under this region. As a result, military action in the Arctic is heating up,
with the United States, Russia, Denmark, Finland, Norway, Iceland, Sweden and Canada holding
talks about regional security and border issues. Several nations, including the U.S., are also
drilling troops in the far north, preparing for increased border patrol and disaster response efforts
in a busier Arctic.
Plate 12: Credit: Romain Schläppy, Paris, distributed by the EGU under a Creative Commons License.
Source: Stephanie Pappas, Live Science Contributor, September 07, 2012
m) Effects on Diseases
Certain vector-borne diseases carried by animals or insects, such as malaria and Lyme disease,
would become more widespread as warmer conditions expanded their range
n) Effect on Rocks: Carbon dioxide is mostly bounded chemically in rocks made from
compounds that chemists call carbonates. High temperature as result of the Greenhouse effect
triggers a chemical reaction which drives carbon dioxide from rock into the atmosphere, this in
turn bakes the rock, decays any organic matter within the rock and leaves it vulnerable to
weathering
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LOOKING FORWARD (MITIGATION OF GREEN HOUSE EFFECT)
This involves intervention or policies to reduce the emissions or enhance the sink of greenhouse
gases. the following policy options suggested below are a combination mitigation models gotten
from various countries like Australia, Philippines, Japan and organizations like the United
Nations Framework Convention on Climate Change(UNFCCC) through its current International
legal mechanism for countries to reduce their emissions:
1. The industrial sector: The first policy area should focus on the industrial sector which
is the main energy and carbon dioxide generator. The reduction of industrial carbon
dioxide can be achieved through these options:
Structural changes affecting material utilization and recycling.
Efficiency improvements
Industrial process change
Fuel-mix changes
Implementation of energy efficiency measures
Promotion of energy conservation
Use of alternative non-CO2 emitting industrial processes
2. The transportation sector: The second policy should focus on the transportation
sector. Reduction in carbon monoxide emission in the transportation sector can be
achieved through the following option
Energy efficiency
Good road network
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Behavioral modification.
Use/promotion of non-motorized transport modes which promotes healthy living
habit e.g. cycling and walking
Development and use of efficient mass transport systems which help to reduce the
number of vehicles on the road and also reduce carbon monoxide emission too
Emission control schemes focusing on improved fuel and vehicle efficiency
Traffic volume reduction measure such as the Unified Vehicular Volume
Reduction Program (UVVRP)
Fuel and vehicle tax policy
3. Renewable source of Energy: The third policy is on renewable. Renewables sources
of energy is extremely important in the mitigation of greenhouse gases. The following
policy options:
Implementation of policies stimulating increased utilization of renewable.
Invitation of international organization to support this policy in developing
countries.
Eliminating fossil fuels, which currently provide 85% of all energy supplies
Research and technology cost trends of renewables (solar, wind, biomass, hydro)
Supply-side efficiency improvements; power plants efficiency improvement;
transmissions loss reduction; replacement of coal plants with natural gas
combined cycle plants
Demand-side efficiency improvements; energy conservation, use of energy
efficient technologies
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Energy-efficient designs for new buildings
4. Forestry and agriculture: The fourth policy is on forestry and agriculture, since they
function as sinks for carbon dioxide emission. The necessary policy options to be taken
are:
Implementation of policies to reverse deforestation
Implementation of policies to cover sustainable forest management of existing
forest resources
Implementation of soil conservation.
Use of tubular polyethylene bio-digesters and urea-molasses mineral block as
nutrient supplement in animal production
Use of sulfate fertilizers to reduce methane emissions
Use of rice straw, water management and low-emitting cultivars
Upgrading of food storage and distribution systems
Promotion and implementation of judicious land –use planning
5. Information: Another policy area is on information. There is a desperate need for
simplified guides, easily accessible information to the public on Greenhouse effect. The
necessary policy option are:
Involvement of environment non-governmental organization to give mass
campaign
Implementation of Agenda 21 (the Rio Declaration on environment and
development, and the statement of principles for sustainable Management of
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forests adopted by more than 178 governments Rio de Janerio, Brazil, 3 to 14
June 1992) in collaboration with relevant organization. Agenda 21 is a
comprehensive plan of action to be taken globally, nationally and locally by
organizations of the united Nations system, Governments and major groups in
every area in which human impact on the environment.
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Conclusion
Despite the series of evidences above some persons still believe and can prove that the
Greenhouse effect is the least our problems. They believe that in our efforts to conserve the
beautiful planet that is our home, we should not fixate on CO2. We should instead focus on
issues like damage to local landscapes and waterways by strip mining, inadequate cleanup,
hazards to underground miners, the excessive release of real pollutants such as mercury, other
heavy metals, organic carcinogens, etc.
No matter which side of the debate we stand, we should realize that reducing greenhouse gases
and moving to a low carbon economy will be associated with substantial health benefits. These
health benefits have a substantial economic impact everywhere, including developing countries.
It only takes a little change in lifestyle and behavior to make some big changes in greenhouse gas
reductions. For other types of actions, the changes are more significant. When that action is
multiplied by the approximately 160 million people in Nigeria or the 6 billion people worldwide,
the savings are significant.
“Individuals Can Make a Difference" identifies actions that many households and individuals
can take that reduce greenhouse gas emissions in addition to other benefits, including saving
your money and improving our health. The actions range from changes in the house, in the yard,
in the car, and in the store. Everyone's contribution counts so why don't you do your share?
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Stephanie Pappas, Live Science Contributor, September 07, 2012, Credit: USFWS
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