1
Introduction
2
1. History
3
2. Causes
4
2.1. Transportation and Utilities
4
2.2. Industrial Production
5
2.3. Electricity
6
3. Global Warming Effects
8
3.1. Sea level rise
8
3.2. Reduction of the Ozone Layer
11
3.3. Ecosystem Change
12
4. Solutions
13
4.1. Evolution of Technology
13
4.2. People's Contribution to Reducing CO2 Emissions
14
Conclusion
16
Bibliography
17
2
Introduction
Global warming is the rise in the average temperature of Earth's atmosphere and oceans since
the late 19th century and its projected continuation. Since the early 20th century, Earth's mean
surface temperature has increased by about 0.8 °C (1.4 °F), with about two-thirds of the
increase occurring since 1980. Warming of the climate system is unequivocal, and scientists
are more than 90% certain that it is primarily caused by increasing concentrations of
greenhouse gases produced by human activities such as the burning of fossil fuels and
deforestation. These findings are recognized by the national science academies of all major
industrialized nations.
Climate model projections were summarized in the 2007 Fourth Assessment Report (AR4) by
the Intergovernmental Panel on Climate Change (IPCC). They indicated that during the 21st
century the global surface temperature is likely to rise a further 1.1 to 2.9 °C (2 to 5.2 °F) for
their lowest emissions scenario and 2.4 to 6.4 °C (4.3 to 11.5 °F) for their highest. The ranges
of these estimates arise from the use of models with differing sensitivity to greenhouse gas
concentrations.
Future warming and related changes will vary from region to region around the globe. The
effects of an increase in global temperature include a rise in sea levels and a change in the
amount and pattern of precipitation, as well a probable expansion of subtropical deserts.
Warming is expected to be strongest in the Arctic and would be associated with the
continuing retreat of glaciers, permafrost and sea ice. Other likely effects of the warming
include a more frequent occurrence of extreme-weather events including heat waves, droughts
and heavy rainfall, ocean acidification and species extinctions due to shifting temperature
regimes. Effects significant to humans include the threat to food security from decreasing
crop yields and the loss of habitat from inundation.
3
1. History
Carbon dioxide (CO2) emissions are the main driver of climate change. CO2 is
released into the atmosphere primarily from the combustion of fossil fuels.Time series
on CO2 emissions from fossil fuels go back remarkably far in history. National estimates
of annual emissions have been made possible by commercial records on the use of
fossil fuels. „This is because carbon emissions are exactly proportional to the
amount of fuel burned based on their chemical properties. As a culmination of statistical
compilations, Boden et al. (2011) have collected time series on annual carbon emissions
going as far back as 1751 in some cases.”
„Countries differ considerably in levels and in trendsof carbon emissions.This has
formed a key challenge in the international climate negotiations.United States,
Australia and Canada have relatively high levels of per capita emissions reflecting their
energy-dependent
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4
2. Causes
Since the Industrial Revolution, human activities such as the burning of oil, coal and
gas, as well as deforestation have greatly increased CO2 concentrations in the atmosphere. As
we can see from figure 1, almost all CO2 emissions (about 96.5%) come from fossil fuels use.
The 3 types of fossil fuels that are used the most are coal, natural gas and petroleum. When
fossil fuels are combusted, the carbon stored in them is emitted almost entirely as CO2.
The main human activity that emits CO2 is the combustion of fossil fuels (coal,
natural gas, and oil) for energy and transportation, although certain industrial processes and
land-use changes also emit CO2.
The climate system can respond to changes in external forcings. External forcings can
"push" the climate in the direction of warming or cooling. Examples of external forcings
include changes in atmospheric composition (e.g., increased concentrations of greenhouse
gases), solar luminosity, volcanic eruptions, and variations in Earth's orbit around the Sun.
Orbital cycles vary slowly over tens of thousands of years and at present are in an overall
cooling trend which would be expected to lead towards an ice age, but the 20th century
instrumental temperature record shows a sudden rise in global temperatures.
2.1 Transportation and Utilities
„Virtually all human activities have an impact on our environment, and transportation
is no exception. While transportation is crucial to our economy and our personal lives,
as a sector it is also a significant source of greenhouse gas (GHG) emissions.”
5
Based on current GHG emission reporting guidelines, the transportation sector directly
accounted for about 28 percent of total U.S. GHG emissions in 2006, making it the second
largest source of GHG emissions, behind only electricity generation (34 percent). Nearly 97
percent of transportation GHG emissions came through direct combustion of fossil fuels, with
the remainder due to carbon dioxide (CO2) from electricity (for rail) and Hydrofluorocarbons
(HFCs) emitted from vehicle air conditioners and refrigerated transport. Transportation is the
largest end-use sector emitting CO2, the most prevalent greenhouse gas. Estimates of GHG
emissions do not include additional "lifecycle" emissions related to transportation, such as the
extraction and refining of fuel and the manufacture of vehicles, which are also a significant
source of domestic and international GHG emissions.
2.2 Industrial Production
The Industry sector produces the goods and raw materials we use every day. The
greenhouse gases emitted during industrial production are split into two categories: direct
emissions that are produced at the facility, and indirect emissions that occur off site, but are
associated with the facility's use of energy.
Direct emissions are produced by burning fuel for power or heat, through chemical
reactions, and from leaks from industrial processes or equipment. Most direct emissions come
from the consumption of fossil fuels for energy. A smaller amount, roughly a third, come
from leaks from natural gas and petroleum systems, the use of fuels in production (e.g.,
petroleum products used to make plastics), and chemical reactions during the production of
chemicals, iron and steel, and cement.
6
Indirect emissions are produced by burning fossil fuel at a power plant to make
electricity, which is then used by an industrial facility to power industrial buildings and
machinery.
2.3 Electricity
The Electricity sector involves the generation, transmission, and distribution of
electricity. Carbon dioxide (CO2) makes up the vast majority of greenhouse gas emissions
from the sector, but smaller amounts of methane (CH4) and nitrous oxide (N2O) are also
emitted. These gases are released during the combustion of fossil fuels, such as coal, oil, and
natural gas, to produce electricity. Less than 1% of greenhouse gas emissions from the sector
come from sulfur hexafluoride (SF6), an insulating chemical used in electricity transmission
and distribution equipment.
The total electricity generation by electric power plants in the United States, net of
internal uses, was about 4.2 gigawatt-hours (GWh, billion watt-hours) in 2007, as shown in
Table 3. Three major fuel groups were used by electric power plants to generate electricity:
coal, at over 48 percent, or more than 2 billion watt-hours; natural gas and propane, at over 21
percent, or nearly 900 million watt-hours; and nuclear energy, at 19 percent, or more than 800
million watt-hours. Renewable sources of energy, such as solar, geothermal, water, and wind,
generated a total of 291 million watt-hours, or 7 percent of total electricity, and biomass
generated 64 million watt-hours, or 1.5 percent, to the net electricity generation in the United
States in 2007 (Table 3).
„Trends in electricity generation for each energy source during the 2003–2007 period are
summarized in Table 3, and charted for major fuel groups in Figure 1. Total electricity
7
generation increased by about 7 percent between 2003 and 2007. Generation from natural
gas and propane showed a significant increase of more than 37 percent during this time.
Generation from all non-biomass renewable energy sources, such as solar, water, wind,
and geothermal, which result in no or minimal emissions of carbon dioxide, actually
decreased during this period. However, use of solar energy to produce electricity
increased by more than 13 percent during the 2003–2007 period. Wind is now the fastest
growing source of electricity due to substantial investments, particularly in the Great
Plains region of the United States, with generation increasing by almost threefold over the
last five years. Major efforts to promote greater use of biomass fuels for electricity
generation have resulted in this source increasing by over 7 percent. It should be noted
that biomass is considered carbon neutral because the carbon released during combustion
is recaptured through plant growth. Woody biomass captures carbon from the atmosphere,
whereas fossil fuels transfer underground carbon to the atmosphere (Biomass Energy
Resource Center 2008). Higher petroleum prices have negatively affected the use of this
fuel for generating electricity, decreasing its share by 51 percent since 2003, and it now
represents only a little more than 1 percent of all fuel types used for electricity in 2007.”
8
3. Global Warming Effects
The effects of global warming are the ecological and social changes caused by the rise in
global temperatures. There is a scientific consensus that climate change is occurring, and that
human activities are the primary driver. Evidence of climate change includes the instrumental
temperature record, rising sea levels, and decreased snow cover in the Northern Hemisphere.
„According to the Intergovernmental Panel on Climate Change (IPCC), most of the observed
increase in global average temperatures since the mid-20th century is very likely due to the
observed increase in human greenhouse gas concentrations.”
Changes have been observed in the amount, intensity, frequency, and type of
precipitation. Widespread increases in heavy precipitation have occurred, even in places
where total rain amounts have decreased. With medium confidence, IPCC (2012) concluded
that human influences had contributed to an increase in heavy precipitation events at the
global scale. Projections of future changes in precipitation show overall increases in the
global average, but with substantial shifts in where and how precipitation falls. Projections
suggest a reduction in rainfall in the subtropics, and an increase in precipitation in subpolar
latitudes and some equatorial regions. In other words, regions which are dry at present will in
general become even drier, while regions that are currently wet will in general become even
wetter. This projection does not apply to every locale, and in some cases can be modified by
local conditions
3.1 Sea Level Rise
Projections of future climate change suggest further global warming, sea level rise,
and an increase in the frequency and severity of some extreme weather events. Parties to the
9
United Nations Framework Convention on Climate Change (UNFCCC) have agreed to
"stabilize greenhouse gas concentrations in the atmosphere at a level that would prevent
dangerous anthropogenic interference with the climate system."
„Core samples, tide gauge readings, and, most recently, satellite measurements tell us
that over the past century, the Global Mean Sea Level (GMSL) has risen by 4 to 8
inches (10 to 20 centimeters). However, the annual rate of rise over the past 20 years
has been 0.13 inches (3.2 millimeters) a year, roughly twice the average speed of the
preceding 80 years.”
Over the past century, the burning of fossil fuels and other human and natural
activities has released enormous amounts of heat-trapping gases into the atmosphere. These
emissions have caused the Earth's surface temperature to rise, and the oceans absorb about 80
10
percent of this additional heat. The rise in sea levels is linked to three primary factors, all
induced by this ongoing global climate change:
Thermal expansion: When water heats up, it expands. About half of the past century's
rise in sea level is attributable to warmer oceans simply occupying more space.
Melting of glaciers and polar ice caps: Large ice formations, like glaciers and the polar
ice caps, naturally melt back a bit each summer. But in the winter, snows, made primarily
from evaporated seawater, are generally sufficient to balance out the melting. „Recently,
though, persistently higher temperatures caused by global warming have led to greater-thanaverage summer melting as well as diminished snowfall due to later winters and earlier
springs.” This imbalance results in a significant net gain in runoff versus evaporation for the
ocean, causing sea levels to rise.
Ice loss from Greenland and West Antarctica: As with glaciers and the ice caps,
increased heat is causing the massive ice sheets that cover Greenland and Antarctica to melt at
an accelerated pace. Scientists also believe meltwater from above and seawater from below is
seeping beneath Greenland's and West Antarctica's ice sheets, effectively lubricating ice
streams and causing them to move more quickly into the sea. Moreover, higher sea
temperatures are causing the massive ice shelves that extend out from Antarctica to melt from
below, weaken, and break off.
„When sea levels rise rapidly, as they have been doing, even a small increase can have
devastating effects on coastal habitats. As seawater reaches farther inland, it can cause
destructive erosion, flooding of wetlands, contamination of aquifers and agricultural
soils, and lost habitat for fish, birds, and plants. When large storms hit land, higher sea
levels mean bigger, more powerful storm surges that can strip away everything in their
path.”
11
In addition, hundreds of millions of people live in areas that will become increasingly
vulnerable to flooding. Higher sea levels would force them to abandon their homes and
relocate. Low-lying islands could be submerged completely.
3.2 Reduction of the Ozone Layer
Ozone depletion describes two distinct but related phenomena observed since the late
1970s: „a steady decline of about 4% per decade in the total volume of ozone in Earth's
stratosphere (the ozone layer), and a much larger springtime decrease in stratospheric ozone
over Earth's polar regions.” The latter phenomenon is referred to as the ozone hole. In
addition to these well-known stratospheric phenomena, there are also springtime polar
tropospheric ozone depletion events.
The details of polar ozone hole formation differ from that of mid-latitude thinning, but
the most important process in both is catalytic destruction of ozone by atomic halogens. The
main source of these halogen atoms in the stratosphere is photodissociation of man-made
halocarbon refrigerants (CFCs, freons, halons). These compounds are transported into the
stratosphere after being emitted at the surface. Both types of ozone depletion were observed to
increase as emissions of halo-carbons increased.
„FCs and other contributory substances are referred to as ozone-depleting substances
(ODS). Since the ozone layer prevents most harmful UVB wavelengths (280–315 nm)
of ultraviolet light (UV light) from passing through the Earth's atmosphere, observed
and projected decreases in ozone have generated worldwide concern leading to
adoption of the Montreal Protocol that bans the production of CFCs, halons, and other
ozone-depleting chemicals such as carbon tetrachloride and trichloroethane. It is
12
suspected that a variety of biological consequences such as increases in skin cancer,
cataracts,damage to plants, and reduction of plankton populations in the ocean's photic
zone may result from the increased UV exposure due to ozone depletion.”
3.3 Ecosystem Change
Climate changes affect each biome and each species individually. Different species
and populations migrate, begin, and become extinct at different rates, climate changes, could
cause the extinction of existing ecosystems and the formation of new ecosystems.
„Ecological changes in climate (temperatures, flooding, warming, and freezing) will
probably eliminate some species, and these species losses may cause the elimination
of entire ecosystems.”
For example we could lose cold-adapted systems such as arctic and alpine communities to
global warming, and low laying areas or islands to be flooded by the sea level rising. All of
these changes could have a disastrous effect on the ecology of earth and its ecosystems, as we
know it today. All climate changes affect each species way of life, the way they eat, sleep, and
survive and interact with each other.
13
4. Solutions
Finding a comprehensive solution to the issue of the emission of CO2 from power plants
means finding a solution for the entire chain, from the CO2 capture itself, through the
transport of the captured CO2, up to its storage, or possible industrial use. From the point of
view of mastering the technology of the entire chain in an economically acceptable manner,
the weakest link in the solution is CO2 capture. So far research and development of capture
technology has not reached the point of commercial utilization under the conditions of power
plant units having regular outputs.
„In addition to power engineering research, the extraction industry is also devoting its eff
orts to the problem of CO2 storage, mainly in connection with the utilization of CO2 to
increase the yields of oil fields. CO2 storage technology, similarly to CO2 capture
technology, before commercial implementation in power engineering, will have to
undergo equipment demonstration and pilot project phases, which will verify the
feasibility and functionality of the designed solution and will provide the foundation for
the more realistic assessment of the economic impacts of the implementation of the new
technology. The problem of CO2 transport can be considered as technically feasible.”
4.1 Evolution of Technology
Hydroelectric reservoirs emit fewer greenhouse gases than the amount previously
attributed to them, says an international team of scientists. Reservoirs used to generate
hydroelectric power emit 48 million metric tonnes of carbon annually, according to a new
study of 85 reservoirs published in this week's online version of Nature Geoscience. That is
14
very small compared to a previous estimate of emissions from all man-made reservoirs,
including hydroelectric reservoirs, of 321 million metric tonnes.
"Our analysis indicates that hydroelectric reservoirs are not major contributors to the
greenhouse gas problem," Jonathan Cole, a limnologist at New York State's Cary Institute of
Ecosystem Studies, said in a release."But there are some caveats," he warned. "To date, only
17 per cent of potential hydroelectric reservoir sites have been exploited, and impacts vary
based on reservoir age, size, and location."In particular, emissions are correlated with latitude
and the amount of vegetation being flooded.
4.2 People's Contribution to Reducing CO2 Emissions
„Citizens can put pressure on their governments to take responsible actions. There is a
lot that governments can do to contribute to the efforts to reduce carbon dioxide emissions”.
To begin with, they can impose stricter regulations on those engaged in activities that
contribute to the problem. This includes requiring factories to curb their emission rates. It also
includes restricting all sorts of transportation manufacturers from selling their goods if those
goods do not meet certain standards.
Governments can also invest in cleaner technology that will help people meet their
needs. For example, countries that rely heavily on coal to produce electricity can begin to
invest in renewable energy resources, such as solar, wind, and hydro power. Putting a halt to
deforestation is another way to reduce carbon dioxide emissions. Like humans inhale oxygen
to live, trees consume carbon dioxide. Yet millions of acres of trees are cut down every year
to make room for other purposes such as urban development and cattle grazing. If this trend
15
were reversed, and replanting projects were undertaken, it would help because the trees would
soak up some of the emitted carbon dioxide.
16
Conclusion
Global warming is one of the most widely debated issues in our world today. There has been a
large amount of query conducted to support both sides of the issue. Regardless of the
opposing viewpoints it cannot be denied that the cosmos is, in fact, warming up. In their
article, Signs from Earth, Appenzeller and Dimick state Theres no question that the Earth is
getting hotter and fast. The real questions argon: How a great deal of the warming is our fault,
and are we go outing to slow grim the meltdown by curbing our insatiable appetite for dodo
fuels? Many scientists believe that gases in the gentle wind are causation Earths temper to
become gradually warmer. This is called global warming. Global warming is the emergence
in the average temperature of the Earths near-surface air and the oceans since the midtwentieth century and its projected continuation. Increasing global temperature will energise
sea levels to rise and will change the amount and soma of precipitation, likely including an
expanse of the subtropical desert regions. Several rate of flow trends clearly demonstrate that
global warming is directly impacting on; rising sea levels, the melting of icecaps, and
significant worldwide climatical changes.
According to Revkin Some of the changes could be beneficial, but most will prove harmful
in the long run. The majority of climate scientists suspects that recent global warming can be
unsaved on a sudden and steadily growing increase in the glasshouse effect caused by the
burning of fossil fuels. If this increase in the greenhouse effect turns out to be harmful, it will
be a matter of too much of a good thing, because the greenhouse effect is a live-giving
process. Without the greenhouse effect, our planet would be uninhabitable. Earths atmosphere
whole kit and caboodle something like the glass of a greenhouse. It is serves as a container
that allows us to survive.
17
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