It is estimated that by
the year 2030, the average sea level will increase by approximately
20cms. This will be due mainly to the melting of the polar ice cap,
but also warming of the atmosphere will heat the upper layers of the
oceans, which will expand when heated.
The Greenhouse Effect and its
Implications
by Tobi Nagy
Some information for those
who may not know much about the causes and implications of the
“Greenhouse Effect” For those of you who have been living under a
rock or asleep for the last 20 years or those who want to know more
about it, here is a brief article.
The Greenhouse Effect maybe
the most important natural phenomena and may lead to major changes
in our lifestyles within our lifetime.
Today, whenever there is a
natural disaster, the Greenhouse Effect seems to be on the agenda.
It wasn’t so long ago that scientists were dismissive of the
Greenhouse Effect and there are some still that do not believe it
exists, just like there are still people out there that think the
world is still flat and the Holocaust never existed. So what is the
Greenhouse Effect? What is the Greenhouse Effect? The Greenhouse
Effect is the culmination of various Greenhouse gases that have been
trapped in the Earth’s stratosphere that is leading to the changing
of the word’s climate. •Under the influence of the sun’s rays, the
earth’s temperature varies from 0 to about 50oC with an average
through night and day, winter and summer, of about 15o C •The
warming is done by rays from the sun, including the very shortest,
ultraviolet (UV) rays and the longest infra-red (IR) rays which give
you that warm feeling when you walk out into the sunshine, much like
an electric radiator warms you when you turn it on and get close to
it. •Some of the incoming rays are reflected back by the clouds in
the sky and others by the sea and land, particularly deserts and
snowfields. Not all those reflected rays go back into space,
instead, the atmosphere re-radiates many of the IR rays towards the
earth making it warmer still. It is this ability of the atmosphere
to re-radiate warm rays which creates the Greenhouse Effect. •Water
vapour, carbon dioxide and certain other trace gases, absorb some of
this radiation and prevent it being sent back into space. This
“blanket effect” keeps the earth warm. History of the Greenhouse
Effect It is not a new phenomena or concept. The term “Greenhouse
gas” was first used in the Nineteen Century, by Irish born scientist
John Tyndall in a paper he wrote in London’s Philosophical Magazine
in 1863. It wasn’t until the 1960’s that Professor Bert Bolin of
Stockholm University worked on the phenomenon. When he discussed it
with fellow scientists they said “This is science fiction. We don’t
believe it”. However by the mid 1970’s things were starting to
change rapidly as scientists were starting to accept he was right.
How do we know the Greenhouse Effect exists? What is the evidence?
1.Scientists have analysed climates on planets like Venus and our
moon. Venus which is covered by a very dense atmosphere of carbon
dioxide. Its surface temperature is around 500o C. Whilst the moon
which has no atmosphere has an average temperature of approximately
-18oC. Our atmosphere keeps the surface of our earth, with an
average of 15o C, some 33o C warmer and thus habitable.
2.Evidence of ice cores Over
the past 160,000 years carbon dioxide and methane levels trapped in
ice cores have varied with global temperature. Scientists have been
able to drill out ice cores from the Arctic and Antarctic and
measure the levels of carbon dioxide and methane.
3.Increase in surface
temperature of approximately 0.5oC over 100 years as carbon dioxide
levels increase Studies conducted by scientists have concluded that
the earth’s temperature remained fairly constant until the start of
the Industrial Revolution. Indeed it did not change much until the
start of the twentieth century.
From 1880 to 1940 there was
a warming of just a quarter of a degree. Most of it was lost between
1940 and 1970. •From 1950 to 1980 the average surface temperature
was 15oC. •Between 1970 and 1980 the temperature average went up by
three-tenths of a degree C. •1987 and 1988 were the warmest years on
record
4.Sea levels are rising and
small glaciers are melting Scientists using satellite and imaging
technology have been able to monitor the melting of polar ice caps
and glaciers. What are the results of the Greenhouse Effect By using
very sophisticated computer modeling, scientists have been able to
predict what the world’s climate will be like when carbon dioxide
levels have doubled. 1.Increase in world’s temperature It is thought
that there will be an increase in the average global temperature by
between 1.5 and 4.5oC . •By year 2030 an increase of 2oC, by 2100 an
increase of 6oC. The warming will be greater at higher latitudes and
in winter. This will lead to the melting of polar ice caps and
glaciers which is already evident, in places like Greenland, the
Arctic and Antarctic. 2.Changes in World’s climate The Greenhouse
Effect will lead to world-wide changes in weather and climate. Some
places may get more rain and storms while other places may get less.
Not all changes will be bad. However, almost everywhere in the world
will have changes in weather, which will have a big impact on our
lives 3.Rising Sea Level It is estimated that by the year 2030, the
average sea level will increase by approximately 20cms. This will be
due mainly to the melting of the polar ice cap, but also warming of
the atmosphere will heat the upper layers of the oceans, which will
expand when heated. For low lying countries in the Pacific like
Tuvalu and Kiribati, and in the Indian Ocean like the
Maldives
luxury resort islands and other countries like Holland may
altogether disappear. 4.Other impacts Other impacts could be the
dieing out of some species of animals and plants, such as coastal
marine environments and coral reefs. Some plants would not be able
to survive temperature increases. It takes thousands of years for
forests to move north or south to cooler climates. According to Joel
B. Smith, co-author of an EPA report states that “such a warming
over a century would require forests to move five times faster than
the fastest rate recorded by paleontologists since the end of the
last ice age”. What are the primary Greenhouse gases? They are a
number of organic compounds which have more than two bonds (i.e 3
atoms). The seven major Greenhouse gases are:
1.Carbon Dioxide (CO2)
2.Ozone (O3) 3.Methane (CH4) 4.CFC’s (Freons F11 & F12) 5.Water
vapour (H2O) 6.Nitrous Oxides (NOx) 7.Ethane (CH3CH3) Where do they
come from? •Most of the Greenhouse gases have resulted from the
burning of fossil fuels. Everything from power stations, motor
vehicles, refrigerators, and factory emissions •However, CO2 also
results from deforestation which releases carbon locked in the soil
when trees are felled. •CH4 is released from agriculture such as
sheep, cattle and manures and places such as tips, sewage treatment
plants and mines. Fossil Fuel contributions Due to the nature of
carbon to hydrogen ratio, different fossil fuels emit different
levels of CO2.
Fossil FuelCarbon to
Hydrogen Ratio CoalApprox. 1:1 Oil Approx. 1:2 Natural GasApprox.
1:4
Table 1: approximate carbon
to Hydrogen ratio for various fossil fuels
Hence combustion of coal
produces twice the CO2 of natural gas CO2 Levels in the atmosphere
Pre Industrial Revolution270
ppm 1988345 ppm Today>355 ppm
Table 2: Levels of CO2 in
ppm (parts per million)
By measuring bubbles of
gases trapped in polar ice, scientists have shown that the amount of
CO2 in the atmosphere prior to the Industrial Revolution was about
270 parts per million (ppm). •A special monitoring station
established atop from the mountain Mauna Loa in the Hawaiian Islands
showed that by 1957 CO2 levels in the atmosphere to 315 ppm, an
increase of 17%. •By 1988, it had passed 345 ppm. A rise in 31 years
of another 11%. An increased total of about 30% since the start of
the Industrial Revolution. •Expert’s further forecast that CO2 will
reach a level of 500-700 ppm by the year 2050, a doubling inside 200
years. Percentage Contribution of Greenhouse gases to the Greenhouse
Effect
CO255% CFC (F-11/F-12)*17%
CH415% NO26% Other7%
Table 3: Percentage
contribution of various Greenhouse Gases
* Please note that CFCs have
been phased out since the mid-nineties
To stablise atmospheric
concentration of various gases at present day levels, the following
reductions would be required instantly
CO260% CH415-20% NO270-80%
CFC (F-11)*70-75% CFC (F-12)*75-85%
Table 4: Reductions of
Greenhouse Gases required to stablise atmospheric concentrations
Remaining Scientific Uncertainty No argument that increasing
concentrations of heat trapping gases will lead to an increase in
average temperatures world-wide. However there is an argument about
the extent in some cases of various positive and negative effects.
1.Uncertainty in effects of
clouds Cumulus- negative cooling effect reflect incoming sunlight
High Altitude clouds- positive effect by trapping infra-red
radiation from earth •This uncertainty explains variation in
temperatures from 1.5oC to 4.5oC. 2.Combustion of fossil fuels e.g.
coal to sulphur dioxide (SO2) has cooling effect. 3.Variations in
sun’s output are responsible for temperature increases. 4.Ocean
levels will naturally increase due to thermal expansion of surface
ocean water and melting of glaciers. •An increase in temperature
will lead to increased precipitation, which will increase ice
thickness at poles, thus reducing sea level. 5.Natural regional
climatic changes, such as deforestation and bushfires, as opposed to
global changes. Policies for Greenhouse Emission Reduction Problems
1.Different countries emit vastly different CO2 levels per capita
2.Countries have very different per capita incomes 3.Very difficult
to work out the warming potential for each Greenhouse Gas in terms
of CO2 equivalent. 4.Emissions of gases from various countries are
not known with certainty Policies 1.Each country can reduce by the
same percentage Existing emission levels are uneven per capita are
taken as standard •Poor countries want to increase fossil fuel usage
2.Each country gets the same
emission quotas on a per capita basis. These countries sell quotas
to rich countries.
3.Rich countries could
reduce emissions by 20% with no reductions required by poor
countries.
Not all rich countries have
high emissions of CO2, and not all poor countries are low emitters
because of deforestation.
4.Assume Australia which is
high income and high Greenhouse Gas emitter per capita is required
to reduce emissions by 20%. •How should it be reduced? By: a)each
state? b)each industry section? Some methods of reducing CO2
emissions that have negative impact on our lives •Better managing of
natural resource; •Reducing waste in manufacturing; •Find
alternative end uses for waste (recycle and reuse); •Buying less
junks and goods that we don’t need (In Australia, estimated to be
worth AUD$10 billion per annum); •Buying quality goods that don’t
need replacing as often; •Recycling more (e.g. it takes about 8
times more energy to convert bauxite to aluminium than it does to
recycle it) Reduced use of motor vehicles; •Increased use of public
transport; •More efficient lighting, heating and cooling; Better
insulation; •Less reliance on electricity and electrical goods and
machines; •More efficient electrical appliances; •More efficient
cars; •Alternative technologies from natural sources such as wind,
thermal and tidal; •Converting landfills and sewage plants into
methane plants; •Bio-fuels such as bio-diesel, methanol and ethanol
production from organic sources Reduce large scale deforestation and
land clearing; •Increase tree planting; •More efficient agriculture
including No till and Conservation agriculture methods; •Organic
farming.
Tobi Nagy runs SDS
Consulting which is a small business enterprise development practice
which focuses on developing enterprises with sustainable business
principles and practices. His website can be viewed at
www.sustainable-development.net
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