EVS PROJECT ON OZONE LAYER DEPLETION
Project work on ozone
layer depletion
Introduction:
The ozone
layer is the layer present in the Stratosphere. It absorbs the harmful
ultraviolet rays that come from the sun. Moreover, it causes harmful radiation
that has a high concentration of ozone (O3) which is harmful to living beings
on the earth. The ozone layer is basically present in the lower stratosphere
that is near about 20 to 35 kilometres above the earth. Moreover, the thickness
of the ozone layer may differ depending upon the seasonal and geographical
changes.
The ozone
layer is important for the earth because it protects the earth from the harmful
ultraviolet radiation. This radiation comes from the sun and is harmful to the
earth’s surface. The flora and the fauna would not be able to survive if the
earth will be directly affected by the harmful ultraviolet rays. Moreover,
humans and animals on earth will face a lot of problems because of excess
heating.
When the
sun's rays split oxygen molecules into single atoms, Ozone is created in the
atmosphere. These single atoms combine with nearby oxygen to form a
three-oxygen molecule — Ozone.
The Ozone
Layer was discovered by the French physicists Charles Fabry and Henri Buisson
in 1913.
Importance of the Project:
The project
work on ozone layer depletion is important as
Ozone
protects the Earth from harmful ultraviolet (UV) rays from the Sun. Without the
Ozone layer in the atmosphere, life on Earth would be very difficult. Plants
cannot live and grow in heavy ultraviolet radiation, nor can the planktons that
serve as food for most of the ocean life. With a weakening of the Ozone Layer
shield, humans would be more susceptible to skin cancer, cataracts and impaired
immune systems.
When the
sun's rays split oxygen molecules into single atoms, Ozone is created in the
atmosphere. These single atoms combine with nearby oxygen to form a
three-oxygen molecule — Ozone.
The Ozone
Layer was discovered by the French physicists Charles Fabry and Henri Buisson
in 1913.
Ozone can
both protect and harm the Earth — it all depends on where it resides. For
instance, if Ozone is present in the stratosphere of the atmosphere, it will
act as a shield. However, if it is in the troposphere (about 10 km from the
Earth's surface), Ozone is harmful. It is a pollutant that can cause damage to
lung tissues and plants. Hence, an upset in the ozone balance can have serious
consequences.
Chemicals
containing chlorine and bromine atoms are released in the atmosphere through
human activities. These chemicals combine with certain weather conditions to
cause reactions in the Ozone Layer, leading to ozone molecules getting
destroyed. Depletion of the Ozone Layer occurs globally, but the severe
depletion of the Ozone Layer over the Antarctic is often referred to as the
'Ozone Hole'. Increased depletion has recently started occurring over the
Arctic as well.
Since the
1970s scientists have observed human activities to be disrupting the ozone
balance. Production of chlorine-containing chemicals, such as chlorofluorocarbons
(CFCs), have added to depletion of the Ozone Layer.
Montreal
Protocol is a multilateral environmental agreement that regulates the
production and consumption of ozone-depleting substances (ODS). It was adopted
on September 15, 1987. The Parties to the Montreal Protocol reached agreement
at their 28th Meeting of the Parties on 15 October 2016 in Kigali, Rwanda, to
phase-down hydro fluorocarbons (HFCs). Countries agreed to add HFCs to the list
of controlled substances, and approved a timeline for their gradual reduction
by 80-85 per cent by the late 2040s.
Objectives
The objective
of this project is to cut down the production and consumption of
ozone-depleting substances, in order to reduce their presence in the atmosphere
and thus protect the Earth's ozone layer.
Ensuring
that existing restrictions on ozone-depleting substances are properly
implemented and global use of ozone-depleting substances continue to be
reduced.
Ensuring
that banks of ozone-depleting substances (both in storage and contained in
existing equipment) are dealt with in an environmentally-friendly manner and
are replaced with climate-friendly alternatives.
Ensuring
that permitted uses of ozone-depleting substances are not diverted to illegal
uses.
Reducing use
of ozone-depleting substances in applications that are not considered as
consumption under the Montreal Protocol.
Ensuring
that no new chemicals or technologies emerge that could pose new threats to the
ozone layer (e.g. very short-lived substances).
Methodology
A new methodology to quantify greenhouse gas
emission reductions from activities that recover and destroy ozone-depleting
substances (ODS).
The
methodology – VM0016 Recovery and Destruction of Ozone-Depleting Substances
(ODS) from Products – was developed by USG Umweltservice GmbH and Energy
Changes Projektentwicklung GmbH. It is
applicable to project activities in any country that recover and destroy ODS
refrigerants, ODS blowing agents or both
Ozone-depleting
substances are industrial compounds – such as chlorofluorocarbons (CFCs) and
hydro chlorofluorocarbons (HCFCs) – which diminish stratospheric ozone. ODS
refrigerants are used in cooling mechanisms such as air conditioners or
refrigerators. ODS blowing agents are used to propel liquid plastic resin for a
wide variety of applications such as insulation foam.
ODS
compounds can contribute significantly to global warming. Some can have impacts
as great as 10,000 times that of carbon dioxide. Recovering and destroying ODS
refrigerants and blowing agents properly prevents them from being released to
the atmosphere.
The
methodology was assessed by two independent validation bodies under the VCS
methodology approval process.
Observation
Ozone
depletion consists of two related events observed since the late 1970s: a
steady lowering of about four percent in the total amount of ozone in Earth's
atmosphere, and a much larger springtime decrease in stratospheric ozone (the
ozone layer) around Earth's Polar Regions. The latter phenomenon is referred to
as the ozone hole. There are also springtime polar tropospheric ozone depletion
events in addition to these stratospheric events.
The main
causes of ozone depletion and the ozone hole are manufactured chemicals,
especially manufactured halocarbon refrigerants, solvents, propellants, and
foam-blowing agents (chlorofluorocarbons (CFCs), HCFCs, haloes), referred to as
ozone-depleting substances (ODS). These compounds are transported into the
stratosphere by turbulent mixing after being emitted from the surface, mixing
much faster than the molecules can settle. Once in the stratosphere, they
release atoms from the halogen group through photo dissociation, which catalyse
the breakdown of ozone (O3) into oxygen (O2). Both types of ozone depletion
were observed to increase as emissions of halocarbons increased.
Ozone
depletion and the ozone hole have generated worldwide concern over increased
cancer risks and other negative effects. The ozone layer prevents harmful
wavelengths of ultraviolet (UVB) light from passing through the Earth's
atmosphere. These wavelengths cause skin cancer, sunburn, permanent blindness,
and cataracts, which were projected to increase dramatically as a result of
thinning ozone, as well as harming plants and animals. These concerns led to
the adoption of the Montreal Protocol in 1987, which bans the production of
CFCs, haloes, and other ozone-depleting chemicals. Currently, scientists plan
to develop a new refrigerant to replace the old one.
The ban came
into effect in 1989. Ozone levels stabilized by the mid-1990s and began to
recover in the 2000s, as the shifting of the jet stream in the southern
hemisphere towards the South Pole has stopped and might even be reversing.
Recovery is projected to continue over the next century, and the ozone hole is
expected to reach pre-1980 levels by around 2075.In 2019, NASA reported that
the ozone hole was the smallest ever since it was first discovered in 1982.
The Montreal
Protocol is considered the most successful international environmental
agreement to date.
Analysis
Ozone-depleting
substances (chlorines and bromines) can be emitted from natural and
anthropogenic (man-made) sources. In the chart we see emissions of
ozone-depleting substances from 1960 onwards. This is measured in tonnes of
chlorofluorocarbon-11-equivalents (CFC11 equivalents). CFC11 equivalents is a
standardized measure to normalise the sum of a range of ozone-depleting
substances to a value equivalent to their potential to deplete ozone; as
we depleting substances are weighted by
their potential to destroy ozone.
Shown in the
chart is the level of natural emissions (which has been approximately
consistent over this period), and total emissions which is the sum of natural
and man-made emissions. Here we see a clear growth-peak-reduction trend in
ozone-depleting emissions, with a rapid rise in emissions (increasing more than
three-fold) from 1960 through to the late 1980s, followed by a similarly fast
reduction in the decades which followed. By 2010, emissions had returned to
1960 levels. This was largely the result of international regulatory agreements
and concerted action to phase-out the production and consumption of these
substances
Result and Conclusion:
The ozone layer,
15 miles above Earth, protects life on Earth by absorbing the hottest
ultraviolet radiation from Sun.
When the
ozone layer is thinned (depleted), more ultraviolet radiation than usual is
measured to reach Earth, raising Earth’s temperature and increasing risk of
sunburn and skin cancer.
Global
warming by one degree between 1965 and 1998 was caused by a rapid increase in
manufacturing of chlorofluorocarbon gases (CFCs) used in aerosol cans,
refrigerators, air conditioners, and certain fire extinguishers, which depleted
ozone, causing the Antarctic Ozone Hole, major depletion in the Arctic, and
more moderate depletion at mid-latitudes.
We can
develop all sources of energy without fear of causing global warming, but we
must minimize pollution.
We can keep
energy costs low because there is no longer a need for special taxes to
discourage use of fossil fuels.
We do not
need to fear the continued warming that has been predicted by current climate
models. The models and their predictions are mistaken.
We do need
to adapt to a world that is now one degree warmer.
We do need
to protect ourselves from increased risk of sunburn and skin cancer. We should
cover up more when in direct sunlight for extended periods of time.
We also need
to protect our belongings from increased risk of deterioration and colour
fading when left outside in direct sunlight. Put your lawn furniture away.
We should
explore ways to restore ozone to pre-1965 levels in order to stop the warming
of the oceans, which is pushing Earth’s thermostat higher.
We can
expect more accurate weather forecasts as scientists gain a better
understanding of the link between ozone and meteorology.
We should
expect improved public policy illuminated by better scientific understanding of
the technical issues.