TOWARDS REGULATION OF DEVASTATING AVIATION
EMISSION: AN ANALYSIS OFTHE CONTAMINANTS OF AVIATION EMISSION, ITS
GLOBAL ENVIRONMENTAL IMPACT AND THE LEGAL
REGIME
Murtala Ganiyu Murgan,*1 Abdul Ghafur Hamid @Khin Maung
Sein2
1 Lecturer, Dept. of Jurisprudence
and International Law, Faculty of Law, University of Ilorin, Nigeria and
currently, a PhD Law researcher, AIKOL, International Islamic University (IIUM)
Malaysia Email: muritalaganiyu@gmail.com
2 Professor, Ahmad Ibrahim Kulliyyah of Laws (AIKOL), International Islamic University (IIUM)
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ABSTRACT |
Keywords: Examination; Contaminants;
Aviation Emissions; Impact; Environment; |
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Throughout
the world, aviation transportation is noted to be increasing steadily largely
because globalization of world economy and economic growth, have made air
transportation affordable for a large number of populations in the world. The
increase in growth of air transportation has led to increase in volume of
aviation emission being discharged on the earth surface. This emission
however, has severe consequences on the global environment inform of
pollution of the atmosphere, stratosphere and lithosphere with high level of
greenhouse gases like carbon dioxide, carbon monoxide, nitrogen oxide and
others. It has been observed that though aviation emission initially
constitutes only 2% of the world’s total greenhouse emission, it has now
become the fastest growing source of anthropogenic greenhouse emission. This
is because aviation emission from annex 1 countries rose by 67% between 1991
and 2005 and is estimated to rise by as much as 90% when aviation emissions
from non -annex 1 countries are included for the period. The problem is that the
potential threat of aviation emission to the global environment is said to be
so much unless it is regulated. This paper therefore, analyses the
contaminants of aviation emission and its impact on human lives and the
global environment. It also discusses the international laws introduced to
curb its escalating growth. A
doctrinal research approach is applied to collect information from primary
and secondary sources on the above. The research finds that aviation emission
has adverse consequences on human lives, local and the global environment and
agree that it would require effective legal measures for its reduction. The
paper recommends that effective implementation of the international legal
regime will guarantee effective reduction of aviation emission. Publisher All rights reserved. |
INTRODUCTION
Aviation emission is the gaseous substance emitted
by air craft and aerospace engines as a result of their combustion activities.
In all activities involving aircraft combustion, aircraft releases gaseous
substance which contains carbon dioxide CO2, carbon monoxide (CO)2,
water vapour, sulphur dioxide SOx, nitrogenous oxide NOx,
un-burnt hydro carbons, soot and aerosol into the atmosphere, through the
burning of fossil fuels such as jet A for (turbine aircrafts) or AV gas for
(piston air craft). The earth environment is the totality of the earth
surroundings where human animals and non-living things exist to fulfil their
desires. It is also the atmospheric surroundings where combustion and emission
activities of air craft and aerospace engines take place. Therefore,
accumulation of carbon
emissions being released in large quantity into the atmosphere by several
aircraft on international and domestic flights, over a long period of time,
contributes in no small measure to inter-boundary and domestic pollution of the
atmospheric environment, which later contribute to global warming and depletion
of ozone layer with serious environmental consequences on human lives, animals
and plants.
The primary products of aircraft combustion process whereby aviation
fuel or aviation kerosene is sprayed
and bunt in the chamber of aircraft are carbon dioxide and water vapour which
constitute salient form of aviation emission. There is also the presence of
nitrogen oxide and sulphur oxide, the emissions coming out of these gases are
characterised as greenhouse gases (GHG) because when emitted into the
atmosphere they trap the infrared radiation from the earth surface and make
earth surface become warmer than before. The process of global warming of the
earth surface which is equally aided by excessive discharge of aviation
emission into the environment, takes place when certain gases which are below
the atmosphere absorb the infrared radiation being sent down on the earth
through energy from the sun. The direct energy from the sun which appears inform
of light and cloud is being absorbed on earth through certain gases called
Greenhouse Gases, which are naturally present below the earth surface.
Reasonable quantity of greenhouse gases will keep the atmosphere in normal warm
temperature but excessive release of greenhouse Gases into the atmosphere
through burning of fossil fuel in the aircraft and other sources too much in
the air, which cannot be absorbed by the earth surface. The heated earth
surface in turn sends the heat energy back into the air space (upper
atmosphere) which eventually leads to global warming of the earth environment.
As regards depletion of ozone layer, the release of gaseous substance called
aviation emission on the upper atmosphere by aircraft and aerospace engines on
domestic and international flights has a direct impact on the depletion of
ozone layer in the upper atmosphere. The consequences of which lead to acid
rain, melting of glaciers skin cancer, air borne diseases destruction of lives,
animals and plants.
Worldwide, aviation transportation has been increasing steadily, largely
due to globalization of world economy and economic growth which have made air
transportation affordable for a large number of populations in the world. The
increase in growth of air transportation has led to increase in volume of
aviation emission being discharged on the earth surface. This emission however,
caused severe consequences on the global environment, inform of pollution of
the atmosphere, stratosphere and lithosphere with high level of greenhouse
gases like carbon dioxide, carbon monoxide, nitrogen oxide and others. It has
been observed that aviation emission constitutes the fastest growing source of
anthropogenic greenhouse emission. This is because aviation emission from annex
1 countries rose by 67% between 1991 and 2005 and is estimated to rise by as
much as 90% when aviation emissions from non- annex 1 countries are included
for the period.[1] It has also been observed that about 3% of both the United States and
European Union’s (EU) total greenhouse gas emission are from aviation emission.
The E.U has forecasted that current growth in trend of emission from
international flights using E.U’s airports will increase by over 150% over 1990
level. This prediction is corroborated by the information in the table 1.1.1
below. Further, it has been observed that the share of aviation to total global
transportation emission is larger if non carbon dioxide emissions are added.
The overall impact of aviation emission is however; potentially double in the
case of aircraft in the air because aircrafts emit greenhouse gases directly
into the atmosphere.
TABLE 1.1.1 GLOBAL AVIATION DEMAND (In billion km)
Year: |
1990 |
2000 |
2010 |
2020 |
2030 |
2040 |
2050 |
2060 |
2070 |
2080 |
2090 |
2100 |
Quantity |
200 |
800 |
1200 |
2000 |
3500 |
4000 |
5000 |
6000 |
7000 |
8000 |
9000 |
10000 |
Table1.1.1 shows the increasing trend of global aviation demand
(1990-2100) in billion Km
The impact of
aviation emission on the environment is said to be more evident in correlation
between increase in carbon dioxide (CO2) emission and increase in
average temperature observed over entire planets. Since 1860, the beginning of
industrial era, the average temperature on the surface of the earth has
increased by 0.8oc. The sudden rise in average temperature since the
start of industrial era, is said to be abnormal compared with trends, both in
view of its relative amplitude and the speed of change on geological time
scale. Therefore, scientific studies have suggested that reducing global
emission by 50 to 80 percent below 1990 levels by year 2050 is necessary in
order to stabilize the climate and avoid most destructive impacts of climate
change. Based on the above, this paper intends to
analyse the contaminants of aviation emission and the impact of aviation emission
on human lives and the global environment as well as discuss the outline of the
legal regime for its control. This approach will enable proper understanding of
the impact of aviation emission on the environment and the justification for
ensuring its reduction through the use of relevant legal measures.
THE CONCEPT OF AVIATION
EMISSION
The concept of aviation emission needs to be
examined in order to have an insight into how aviation emission impacts the
environment. The concept of aviation emission is however examined as follows:
Definition of Aviation
Emission
Aviation emission can be explained as the gaseous
pollutants emitted by air craft and aerospace engines as a result of their
combustion activities. According to Oxford Advance Learner’s dictionary of
English, aviation emission is the sending out of carbon dioxide and other gases
into the atmosphere by aircraft. Also, according to the report of Global
Aviation Emission Inventories, aviation emissions are described as the smoke
pollutants or gases from aircraft which originate from fuel burnt in air craft
engines Further, the Kyoto Protocol to the United Nations Frame work
Convention on Climate Change, though did not define aviation emission , brings
to our awareness about the existence and limitation of aviation emission when
it states in article 2 (2) that; “parties shall pursue limitation of
reduction of emission of greenhouse gases not controlled by Montreal protocol
from aviation by working through International Civil Aviation Organization. In all activities involving aircraft
combustion, aircraft releases gaseous substance which contains carbon dioxide
C02, carbon monoxide(C0)2,water vapour, sulphur dioxide
S0, nitrogen oxide N0x, unburnt carbons, soot and aerosol into the atmosphere,
through the burning of fossil fuel such as
jet A for (turbine aircrafts) or Av gas (for piston aircraft).
Therefore, the above shows that the emitted pollutants from aircraft emanating
from the burning of the various gases above, are referred to as aviation
emission.
Scope of aviation emission
In a broad
sense, the scope of aviation emission under a typical aviation industry,
extends beyond emission from air craft engines and aviation technologies to
include emissions from ground airport vehicles and those used by passengers and
staff to access airport, as well as through emission generated by production of
energy used in airport buildings, the manufacture of aircraft and construction
of airport infrastructure. However, for the purpose of this research, our focus
of aviation emission shall be limited to emissions from civil aviation aircraft
engines and aerospace engines only and even excluding military aircrafts.
Specifically, this study will focus on emission emanating from civil aviation air
craft engines being accounted and reported for under the regulations of
International Civil Aviation Organization, which is the body responsible for
regulation of aviation emission.
THE CONTAMINANTS OF AVIATION EMISSION
Contaminant is defined as biological,
chemical or physical substance which its sufficient supply can adversely affect
living organism and the environment. By nature, aviation emission is in the
form of gaseous pollutants which are made up of greenhouse gases and other
pollutants that affect the living and the environment. The role of Greenhouse
gases which form the major part of aviation emission is explained below:
Greenhouse gases
According to Oxford
Advanced Dictionary of English, Green house in technical context, is used to
explain the atmosphere play in warming the earth surface. Short solar radiation
passes through the atmosphere and absorbed by earth surface, this is then
re-emitted and reflected back to the atmosphere by gases like carbon dioxide,
methane, nitrous oxide, ozone etc which are known as greenhouse gases. Also,
the Special Assessment Report (1999), of Intergovernmental Panel on Climate
Change while reporting on the effect of aviation emission on global warming,
refers to greenhouse gases as the cause of global warming. According to the
report, such greenhouse gases as carbon CO2, nitrogen oxide NOx
water vapour H2O, Sulphate aerosol and soot cause global warming
when emitted form air craft engines. Further, according to Thornton J. Beckwith
S, greenhouse gases which act to maintain the earth’s relative warm
temperature. But too much of trapping of the warmth from the sun in the lower
atmosphere caused by too much presence of greenhouse gases such as carbon
dioxide ,methane, nitrous oxide and others in the lower atmosphere leads to
global warming. Generally, greenhouse gases (GHGs) are a term used for gases
which cause warming of the earth, although (GHGs) production occurs naturally,
greenhouse gases are majorly produced by burning of fossil fuel such as coal, oil
gas, petrol, and kerosene. The use of fossil fuel which has contributed
immensely to industrialization and aviation development, has also caused a
steady increase in the release of high level carbon gases and other pollutants
into the atmosphere. These greenhouse gases when emitted into the atmosphere,
are like blankets, and are known for trapping heat in the atmosphere instead of
allowing it to radiate back in to the space. As a result of this, the
atmosphere is over heated at an abnormal rate and this leads to global warming
and a change in weather pattern. In combustion process, aviation fuel
(kerosene) is sprayed at high pressure into the combustion chamber of the jet
engine where it mixes with hot high pressure air supplied by the compressor and
when ignited ,the products of this
process are carbon dioxide and water vapor which characterize the greenhouse
gases, because when emitted into the atmosphere they enhance natural greenhouse
effect by trapping the infrared radiation from the earth surface.The greenhouse
effect is a natural phenomenon that warms the earth to support life and without
it, the earth temperature will be a frozen -180c (Celcius) instead
of normal/average of +150c. The greenhouse effect is believed to
cause abnormal warming of the atmosphere leading to melting of the polar ice
caps and flooding of the low land mass. The major greenhouse gases and other
pollutants which form the components of aviation emission and contribute to
global warming and other atmospheric changes are explained as follows:
Carbon dioxide (CO2)
Carbon dioxide is a gaseous
pollutant in aviation emission which contributes to global warming and climate
change. It is estimated that the current world wide fleet of air craft produces
about 2 to 3% of the fossil fuel released into the atmosphere. According to
report, the combustion of one kilogram of aviation emission kerosene directly
results in emission of about 3160 grams of CO2 into the atmosphere.
Carbon dioxide (CO2) is believed to have a very long atmospheric residence
time (approximately 100years) and C02 emitted from air craft becomes
well mixed with CO2 from other fossil fuel sources. Since the effect
of CO2 on climate change is direct and depends on atmospheric
concentration, aviation emission of CO2 will continue to be a matter
of environmental concern in view of projected growth in aviation emission.
Nitrogen Oxide (N0x)
Nitrogen Oxides are part of greenhouse gases.
Nitrogen oxides and oxygen are readily formed by direct reaction of nitrogen
and oxygen in high temperature combustion process that occurs in jet engine
aircraft because, air contains 78% of nitrogen and 21% oxygen. This combustion
process produces several oxides of nitrogen like nitric oxide (N0x)
and nitrogen dioxide (N02) both termed as (N02) .This
nitrogen oxide (N0x) is known to have great influence in the
chemistry of troposphere and atmosphere especially in ozone production and
destruction processes. A natural occurrence of gas in the atmosphere which
about 80 -90% reside in the stratosphere is known as ozone. This is produced by
reaction of oxygen molecules and ultra violet radiation (UV) from the sun in a
process called photo dissociation. Chemical reaction in a pollution free
atmosphere ensures a balance between production and destruction of ozone which
leads to a steady state of abundance of
gas in the stratosphere and this is called ozone layer. The ozone layer doubly
acts as the shield that protects biological system on the earth surface from
damaging ultra violet radiation from the sun and also acts as a greenhouse gas
but its efficiency in this role depends on its altitude and latitude.
Therefore, a discharge of nitrogen oxide in the upper stratosphere from
aviation emission, has a profound effect upon atmospheric ozone. In addition,
nitrogen oxide emissions below cloud level are washed out of the atmosphere as
acid rain.
Methane
Methane is another
pollutant of aviation emission among the greenhouse gases. Though, not emitted
in large quantity like carbon dioxide, methane also plays an important role in
atmospheric changes through reactions with nitric oxide and other hydro carbon
products. Methane is known to represents 15% to 20% of man-made additions to
global warming, despite the fact that methane only lasts for a period of ten
years in the atmosphere, it absorbs twenty to thirty times more heat than
carbon dioxide. Methane has warming effect on the atmosphere and too much
presence of methane in the atmosphere from aircraft emission has global effect
on climate change.
Water Vapour (H20)
Water vapour is a pollutant
which constitutes an active radiative gas in aviation emission, therefore,
additional water vapour in the atmosphere can directly modify the radiative
capacity of the earth by enhancing greenhouse effect. Water vapour which is
another primary product of combustion in air craft jet engine however has its
effect on the atmosphere influenced by its altitude. The potential climatic
effect of water vapour emission by air craft in this respect, depends on the
relative contribution of the emission to the back ground water vapour level in
the atmosphere. Water vapour H2O, is emitted by very large air craft
in flight at high altitude. Emission of water vapour from aircraft engines in
conjunction with soot and sulphur compounds, form condensation nuclei and
trigger additional cloud formation in the atmosphere which indirectly
contributes to radiative forcing and climate change. Condensation
nuclei forms when soot particles present in the air craft emissions are
activated, these condensed water vapour keeps growing in size until clouds are
formed. These clouds called condensation trails or contrails may not stay long
and may be persistent in the atmosphere based on the background temperature and
high humidity level. Whenever the air is super saturated with water and
temperature is below freezing point, formation of persistent contrail with
longer residence period in the atmosphere takes place Water vapour is
considered in determining radiative balance and chemical composition of
atmosphere because of the dramatic role it plays in polar ozone loss through
formation of polar stratospheric cloud.
Sulphur (Oxide S0x)
Some amount of sulphur
about 0.04 – 0.05 % is contained in a standard jet engine fuel (Aviation
kerosene). In a combustion process, the oxidation of fuel sulphur leads to
production of sulphur dioxide (SO2) which further reacts with other
species in the exhaust of plane to produce sulphur trioxide (SO3)
and possibly sulphuric acid (H2SO4). The atmosphere shall
be affected by these oxides of sulphur by increasing sulfate aerosol level,
thereby enhancing heterogeneous processing of halogen reservoir gases and by
reactivating carbon soot particulate to bring about condensation nuclei which
will bring about an increase in the formation of contrails and cirrus clouds
Carbon monoxide (C0)
Carbon monoxide is a
poisonous gas contained in aviation emission. It is not a greenhouse gas
contributing to climate change, but a product of incomplete combustion with a
particular concern to the health of people in urban environment.C0 reduces the
atmosphere’s hydroxyl content which acts as nature’s detergent. Carbon monoxide
is known to be a common irritant when emitted as a surface level pollutant, it
is primarily generated by aircraft at low engine power level at idle or taxi
time by aircraft.
Products of incomplete Combustion
Due to incomplete
combustion of fuel, air raft engines emit a number of effluents which include
volatile organic compound (VOCs) such as benzene, toluene formaldehyde and 1.3
butadiene. There are also non methane hydro carbons (HC) such as alkaline
aldehydes and aromatase, carbon monoxide (CO) and carbon soot (smoke). Soot is
generated at high engine power level while hydro carbon and carbon monoxide are
generated at low engine power level. The quantity emitted by any air craft
engine however depends on the combustion efficiency of the engine. The
atmospheric effects of products of incomplete combustion are however mostly
localized. For instance, soot and unburnt hydro carbons are responsible for
poor air quality and smog around airport while carbon monoxide is a common
irritant emitted as a surface level pollutant. As a matter of fact initial
concern about atmospheric impact of air transport focused on these localized
environmental problems.
THE IMPACT OF AVIATION EMISSION ON THE ENVIRONMENT
It is observed that the
above discussed contaminants of aviation emission have serious impact on human health. Not only that, the contaminants
also have serious local, regional and global effects on the environment.
However, before discussing about the impact, the concept of environment shall
briefly be discussed for the purpose of better understanding of discussion on
the impact.
Concept of environment
Environment can be
explained as the constituent of the totality of the earth surroundings which
includes the land, the sea, the air, the vegetation and human life. The earth
is therefore a source of human sustenance that human beings depend upon for
food, fuel machine material and even spiritual material. The English language
term “Environment” is known to be borrowed from French word “environner.”
Webster dictionary defines environment on the original French meaning as
“circumstances, object or condition by which one is surrounded”. It states
further that environment is the complex physical, chemical and biotic factor,
including climate, soil and living thing or an ecological community and
untimely determine its form and survival. In law content, environment may relate
to a limited area or the entire planet including atmosphere and stratosphere.
The international court of justice defines environment to include social
dimension, stating that environment represents the living space, quality of
life and the health of human beings including generation unborn. However, the
international legal instruments have referred to environment to include water,
air, land and their inter relationship as well as relationship between them and
living organism. Specifically, the United Nations Stockholm Conference on Human
Environment (UNCHE)1972, refers to man’s environment as that which gives him
physical sustenance and affords him opportunity for intellectual, spiritual,
moral and social growth, adding that both the
natural and manmade environment are made essential for wellbeing of
human life. From the above, it can be understood that the environment is the
atmospheric surrounding where human beings animals and plants survive and the
scope of environment includes water, air and land. In the context of this
study, this same environment is referred to as the surrounding where combustion
and emission activities of aircrafts and aerospace engines take place. On the other hand, impact shall simply be explained
to mean the effect, the result or consequences of an action. Based on the
above, the impact, the effects or negative consequence of aviation emission on
the state of earth environment shall now be discussed.
Aviation plays a
significant role in social and economic life today, in the sense that it
provides a quick, reliable and safe means of transportation to people whether
for business holidays or family tours. Besides, aviation offers easy access to
remote areas of the globe and has virtually turned the whole world into a
global village. Aviation also shortens travel time considerably when compared
to other types of travelling. Because aviation enables goods and services to be
transported to their destinations quickly, it has contributed to increase in
the volume of import and export of goods in the world. Altogether, aviation
accounts for 1.6 billion air lines passengers in year 2000, over 29million
tonnes of freight in 1998while 40 % value of world manufactured goods are
transported by air as at today. In 1993,the world airline made an annual
turn-over of US $307 billion while aviation industry generated employment of
over 28 million world-wide in year 2000 and many jobs also created as a
multiplier effect in relevant sectors like hotels, travel agencies and car hire
services. However, it is important to note that despite the tremendous benefits
mentioned above, aviation industry has its bad side in the sense that aviation
emission being generated by aircraft engines during air transportation has a
negative impact on the environment both at local and global levels.
Local and Regional impact of aviation emission
By local and regional
impact of aviation emission, we mean the domestic or national impact as well as
international impact of aviation emission on the environment. The above is discussed
as follows:
Pollution of air environment around airports
In the environment around
the airports, emission of gaseous and particulate products from aircraft jet
engine during landing and take-off cycles had for long been recognized as a
strong factor contributing to urban smoke problem and photo chemical smog
generation. The level at which aircraft exhaust emission within the airport and
airport neighbourhood has great influence on the environment around the airport
as emission of critical gases has
critical effects on climate process of the area. Emission of carbon monoxide
from aircraft engines are at the peak when aircraft is stationery at the
airport. Carbon monoxide when combined with haemoglobin in blood to form carbon
haemoglobin will reduce oxygen capacity of the blood and dangerous to the body
when inhaled in large concentration as this may lead to high rate in death of
human beings and animals living around the airports. In the 1990s, a number of
published epidemiological studies found association between elevated level of
air pollution on one hand, mortality and respiratory health care symptoms on
the other. Although, there were some disagreements over the nature o0f the
symptoms, some effects manifested in lung function deficits, to aggravation of
symptoms of asthma while some effects emerged only after a long term cumulative
exposure.
It has also been recognized
that the environment and the people living around the airports are subjected to
serious problem of environmental odour by aviation pollutants like sulphur
dioxide SO2 and ground level ozone caused odour problem, especially
when mixed with serious odour from aviation kerosene. This type of
environmental odour is known to be irritable to lungs, reduce resistance to
infection and aggravate heart disease, asthma and bronchitis. A relevant
example is that of Chicago O’ Hare international airport which its annual
record of 900,000 flights operation, ranks it as one of the top of five toxic
pollution source in the state of Illinois, in America.
Particulate like soot is known for contributing to formation of
smog and hazes around the airport and urban areas which reduce visibility
during vehicular movement. This formation also destroys the soil and aesthetic
value of buildings and properties around the airports. Hydro carbons like
Benzene and other related carbons are carcinogenic when emitted from aircraft
engines and persistent exposure to these carbons by human beings is deadly.
For example in 1993, aircraft at
US air ports produced 350million pounds of VOCS and N0x during their
landing and take-off cycles (LTOs), more than twice their 1970 level. An
airport arriving and departing aircraft, creates much if not more than ground
level VOCs and N0x than their industrial neighbours. This type of
development portends a dangerous impact to the people and the airport
environment in the United States of America.
Trans boundary air pollution and acid deposition
Aviation emission impacts
on the environment through trans boundary air pollution in the sense that notable oxides of sulphur
and nitrogen which are observed to have capacity to remain airborne for several days or travel through a
number of kilo meters, contribute greatly to secondary pollutants that damage
the environment when transported and emitted into the air of another
country by aircraft engines. This is the
case when sulphur oxide and nitrogen oxide normally oxidize to form sulphates
and nitrate particulates which also precipitate independently into a dry fall
or combine with cloud vapour to form sulphuric nitric acid and subsequently
precipitating as snow into acidic wet fall. Occurrence of dry fall can be localized,
whereas occurrence of acidic wet fall may occur at a considerable distance away
from original source of emission. The fact that these oxides have the capacity
to remain air borne for several days and travel thousand kilo meters before
being deposited has made it possible for the oxides to be transported and
deposited on trans boundary basis via aircraft engine emission with devastating
consequences on the lives of people and the environment of the deposited
country in other jurisdiction. Despite remarks that air craft engine emission
makes only a minimal contribution to long range pollution, the fact still
remains that aircrafts are non stationery sources of long range pollution and
also the fact that aircrafts emit these oxides into the atmosphere directly at
high altitude, reinforces the capacity of the oxides to stay for longer period
in the atmosphere and to be transported over long distance.
Acid deposition by aircrafts through long range air craft
emission, usually results into acid rain which has serious acidizing
consequencies on forests, wet land, and river courses. Acidizing of river
courses has serious effects on fish and water lives. Leaching of plant
nutrients and radiation in forest productivity especially at altitude over 600
meters are the serious effects of acid deposition in forest areas. Also, acid
deposition and acid rain have serious corrosive effect on metal monuments and
historic buildings, thereby affecting the environment.
Global impact of Aviation Emission
The global impact of
aviation emission globally impacts on Climate Change, haze, acid rain and
atmospheric ozone concentration as follows:
The impact of aviation emission on Climate Change
Aviation emission impacts a
lot on Climate Change because international aviation has been experiencing fast
growth and this growth is known to be connected with socio economic and
environmental harm which centres impact on climate change. A change of climate
or climate change is that which alters the composition of the global atmosphere
in addition to natural climate variability observed over comparable time
periods .It is a change in the statistical distribution of weather over period
of time that ranges from decade to millions of years. It may be a change in
average weather, or a change in distribution of weather events and may be
associated with a specific region or occur across the whole hearth and it is
presently known as a change in modern climate. The UNFCC describes climate
change as an alteration in the atmospheric temperature caused by greenhouse gas
which is accumulating in the earth’s atmosphere as result of human activities
and which cause surface air temperatures and subsurface ocean temperature to
rise. However, climate change is a wider phrase which includes global warming
as one the extreme weather events arising out of climate change.
Consequences of climate change which according to
Intergovernmental Panel On Climate Change include rising temperature and extreme
weather, disaster such as flood and draughts have already affected millions of
people. There is also, illness, loss of forest and biodiversity, dislocation of
communities and socio economic decline all of which will be hardest on the poor
and the developing countries. Climate change is predicted to lead to variety of
other impact such as melting of glaciers and mountain snow cap, a rise in sea
levels due to melting of glaciers, extreme bad weather, lower agricultural
productivity, increase in vector borne diseases and extinction of higher level
species.
Aviation emission globally
impacts on the environment by bringing about global warming which changes the
radiative balance of the atmosphere and eventually lead to climate change. It
also impacts on human health by adversely affecting the air quality as
explained above. However, an efficient understanding of the impact of aviation
emission on climate change will rely on clear understanding of contribution of
aviation emission to climate change as contained in the published reports of
Intergovernmental Panel on Climate Change from 1990 - 1999. According to the
comprehensive report of IPCC (1999) on the effect of aviation emission on
global atmosphere, the aviation sector represents approximately 3.5 % of the
global anthropogenic radiative forcing which was a great measure of warming. This
was caused by a group of Green House Gases emitted from aircraft engines mainly
(C02 and N0x, water vapour, sulphate, aerosol and soot).Aviation
emission was estimated to increase to 5 percent in 2050. Several other
researches carried out since 1999, confirmed this position and stated that
aviation emission has been projected to
increase above 35% due to expected growth in air travel. Although, 3.5%
radiative forcing may be said to be low
comparatively, severity of aviation emission which may be explained by
considering the following three factors; firstly, air craft emissions are
injected directly into the upper troposphere and lower stratosphere and the
impact of burning fuel at altitude is about double than burning fuel on the
ground.
Secondly, the impact of burnt mixture of emission species was
calculated to be two or four times more than exhaust of carbon dioxide alone
from aircraft, causing radiative
forcing. Thirdly, the rapid growth in aviation sector is expected to continue
as globalization of industry and commerce progresses. Further, the fourth
assessment report of IPCC fixed total air transportC02 emission
at280mt in 2000 and 282Mt in 2005.It was forecasted in the report that such
emissionwillbe584 Mt in2010, 860 Mt in2020 1262 Mt in 2030 and 2377 Mt in 2050.
Also report from International Air Transport Association (IATA) 2010 indicated
that air travel and freight volume have increased tremendously. Air lines are
expecting to have 16 billion travellers and handle 400 million tons of cargo in
2050(a strong growth from 2.4 billion passengers and 43million tonnes of cargo.
The above shows the increasing of growth of aviation emission and its
corresponding impact on global warming as crystalized by greenhouse effects. It
also shows the need for urgent reduction in aviation emission as a way of
combating climate change. However, further understanding of the impact of
aviation emission on climate change, can be appreciated by a careful
examination of the negative contributions of carbon dioxide water vapour and
other processes of aircraft engine emission to global environment.
Aircraft emission contains carbon dioxide with serious global
warming impact on the environment. Carbon dioxide C02, has a
significant warming effect on the environment. Carbon dioxide is relatively
straight forward to estimate as it is effectively a direct function of aircraft
fuel burn. Aviation emission represents 2.25% of total annual anthropogenic
human induced carbon dioxide emission at the global level, according to
International Energy Agency statistics. At present, carbon dioxide accounts for
0.9% of cumulative anthropogenic emission since the pre industrial era because
affordable mass air travel is relatively a recent phenomenon. The impact of
concentration of Carbon dioxide emission in the atmosphere as reported above is
warming of the earth surface, melting of the glaciers and adverse climate
change consequences.
Air craft emission produces water vapour with global warming
impact on the environment. Water vapour (H20) is another pollutant
emitted by very large aircrafts at high altitude with warming effect. Under a
certain atmospheric condition, water vapour forms condensation contrails and
visible lines that form in cold humid
atmosphere and are known to have a global
warming effect though not as much as that of carbon dioxide C02 and
nitrogen oxide N0x. In addition, the amount of dissolved oxygen in
water is inversely related to temperature as such there will be less oxygen
available for animals and plants at high water temperatures and a slight change
in water temperature can alter the growth rates and species composition of
aquatic organisms like fish.
Impact of aviation emission
on Haze
Aircraft emission is
responsible for formation of haze with global impact on climate change. It has
been observed that mixture of particulates called soot and unburnt carbons
emitted by air craft engines are responsible for poor air quality, smog and
haze around the airports. Soot absorbs heat, it has a warming effect and
influences the formation and properties of cloud globally. This is also
responsible for poor visibility in vehicular movements around the airports.
Impact of aviation emission on acid rain
It has been observed that
aviation emission contributes to acid rain which has global effect on
environment. Sulphur dioxide S02
emitted by air crafts, contributes to acid rain after mixing with
Nitrogen dioxide and water vapour to produce sulphuric acid. Apart from being
emitted at altitude, emission of sulphur below the cloud level washed away as
acid rain .The effect of acid rain on the environment is that it causes severe
pollution of water, acidify lakes, damage to ,plants and animals in the
environment, as well as corrosive effects on metals, monuments and buildings. Acid
rain is a major global problem. It is said to have caused decline of forest in
central and Eastern Europe and many lakes in Scandinavia and Canada are now in
capable of supporting life because of acidification. Lake acidification is
known to have killed some fish population and can slow forest growth.
Impact of aviation emission on atmospheric ozone concentration
There is a good evidence
that aircraft Nitrogen oxide NOx emission affects climate change by
producing ozone (O3) with a warming effect and destroying methane
(CH4) with a cooling effect. The observation which is restricted to
the present commercial fleet of subsonic aircraft whose emission occurs in the
upper troposphere and lower troposphere said that emission of nitrogen oxide N0x
by aircraft in the upper Troposphere( UT) / Lower stratosphere(LS) increases
ozone concentration in those regions of the atmosphere, but similar emission in
the upper stratosphere tried to deplete ozone, thereby minimally offsetting the
N0x induced increases with ozone of upper troposphere and lower
stratosphere. Although, the degree of this occurrence is not yet quantified, it was estimated that
in 1992, aircraft reduced the erythema dose rate of solar ultra violet radiation reaching the surface of the earth
by 0.5% at 45degree North in July that year. Comparatively, the calculated increase
in erythema dose rate due to ozone
depletion was about 4% over 1970 -1992 at 45% North in July. The above appears
to be an increase in column ozone and decrease in UV radiation reaching the
surface of the earth. The impact of this is that the increase in Ultra Violet
radiation (UV) is detrimental to human health as it leads to suppression of
human immune system, sunburn. Skin cancer and cataract. It also reduces growth rate of forest and
productivity of crop and disrupts aquatic life in the ocean.
It has been observed that aviation transport accounts for 43%
of N0x emission in the United States and 60% in Europe. According to
report, nitrogen oxide depletes ozone at higher altitude, while in another
sense, below a level of 12km, N0x increases the amount of ozone,
acting as a potent green-house gas. In 1998, a published study in a scientific
magazine, twenty four scientists concluded that air craft emission of nitric
oxide interact with sunlight in the upper troposphere to produce ozone
resulting in the formation of more green-house gas than previously thought. In
Europe, tropospheric ozone has increased by 500% since 1970, concentrations are
increasing one to two percent per year in Northern Hemisphere.
From all the above, it has been seen that aviation emission has
adverse socio economic and environmental effects on the lives of people and the
earth environment. It therefore requires necessary legal intervention to halt its further
damage.
THE LEGAL REGIME
In realisation of the
impact and bad consequences of increasing aviation emission on the environment,
the international community responded to the adverse atmospheric effects of
aircraft engine emission in two ways: One approach was to control aviation
emission through ratification of international conventions and protocols by
member states. The notable convention and protocol for this are the United
Nations Framework Convention on climate change, UNFCCC (1992) and the Kyoto
protocol to the UNFCCC (1977). Under Public International Law principle, such
convention and protocol are to be signed, ratified and domesticated by member
states to become implemented as part of the domestic Acts of a state. The other
approach has been to address reduction in aviation emission directly from air
craft engines through the regulatory regime of International Civil Aviation
Organization (ICAO). The regime include the Standard Recommended Practices on
air craft engines (SARPs) and other regulations contained in annexe 16 volume
II of the Chicago convention 1944.The ICAO regulations equally need adoption
into national regulations for the purpose of implementation by member states,
in line with ratified convention.
The ICAO is the global organization responsible for regulation
of international civil aviation. Its functions include making laws on
international standard and best practices in aviation, which are to be
implemented among member states. Based on this approach, the International
Civil Aviation Organization (ICAO) has since June 1981 adopted a continually
updated international standard and recommended practices on aircraft engine
emission in exercise of its laws making power under article 37 of the Chicago
Convention on international civil aviation 1944. The SARPs contained in annex
16 vol. II call for prevention of international oil venting and established
standard for air craft emission control. Added to this, annex 16 volume II of
Chicago convention limits certain aircraft emission through engine
certification process, depending on the age and type of aircraft. It also
established highly technical process for measuring emissions. The emissions
under ICAO control include, smoke, hydro carbon, carbon dioxide CO2
and Nitrogen Oxide NO2 from new engines. The above international
conventions and regulations are however expected to be applied and implemented
by member states of ICAO for achieving effective reduction in the
increasing volume of aviation emission.
CONCLUSION
From the above, this paper
has analysed the definition of aviation emission, the contaminants of aviation
emission. It also analysed the impact of aviation emission on human lives, the
local and trans boundary environment, as
well as the global environment. It is
now clear from the above that contrary to the claim that aviation emission only
contributes 2% of the total global emission and thus has little impact on
climate change, aviation emission has a significant impact on climate change
both locally and globally and this impact will continue to increase as a result
of global increase in aviation transportation .It has been established that
aviation’s plea to continue to grow above 2% will constitute serious threat to
the environment. It is also established that the impact of burning aviation
fuel at altitude is about double than that of burning same fuel on ground. It
has been noted that the impact from the mixture of emission from air craft goes
beyond radiative effect of C02 alone, as the mixture of such species
was calculated to be two or four times more than exhaust of carbon dioxide
alone from aircraft, as the mixture is known for causing radiative forcing.
Also, it was observed that as long as globalization of industry and commerce
increases, the fast growth of aviation sector is expected to continue. Added to
the above, various reports have pointed to the fact that future scenario of air
transportation and aviation emission shall continue to rise. The report of
International Air Transport Association (IATA)
2010, indicated that air tr and freight volume has increased
tremendously and predicted 16 billion
travellers and 400 million tons of cargo for air lines in 2050. The Intergovernmental
Panel on Climate Change (IPCC),in its fourth assessment report, put total air transport carbon dioxide at
280mt in 2005 and later predicted that such emission will be 594mt in 2010,
860mt in2020, 1262mt in 2030 and 2377 in 2050. The purport of these reports is
to show that as a result of continuous fast growth in global air
transportation, aviation emission will continue to grow in future and this will
constitute a serious threat to the environment unless a decisive action is
taken in term of applying the regulatory measures for achieving reduction in
the global volume of aviation emission.
The impact of aviation emission or the consequences resulting
from continuous excessive discharge of aviation emission on the global environment include are also found to
include global warming and climate change, atmospheric pollution with adverse
effect on air quality leading to asthma, bronchitis and other lung diseases.
Prevalence of Aviation emission also lead to haze, fog and bad weather resulting in flight delays
and cancellation and poor visibility for vehicles around the airports. It also
causes atmospheric ozone depletion resulting in skin cancer and cataract. It further causes acid rain
resulting in acidification of lakes and rivers leading to the killing of fishes
of fishes and water lives.
As already discussed above that aviation emission is fast
increasing in growth and that the increase has adverse impact on human lives
and the global environment, it is hereby recommended that the UNFCCC
convention, the Kyoto Protocol and the ICAO international Standards regulations
introduced should be effectively applied and implemented by member states so as
to achieve effective reduction in aviation emission globally.
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