Ozone Depletion and the Montreal
Amit Kumar Das
Amit Kumar TO
Amit Kumar Das
The atmosphere of the Earth is divided into 5 layers.
The layers are: troposphere, stratosphere,
mesosphere, thermosphere and exosphere.
Ozone is a triatomic form of oxygen (O3) found in
Earth’s upper and lower atmosphere.
The majority of the atmosphere’s ozone resides in
the stratosphere, which extends from 6 miles above
the Earth’s surface to 31 miles.
Humans rely heavily on the absorption of ultraviolet
B rays by the ozone layer because UV-B radiation
causes skin cancer and can lead to genetic damage.
The lowest layer (about 15 km from the ground)
Contains normal air composed of N2, O2, water vapour, CO2,
Temperature decreases with altitude
Above the troposphere
Temperature increases with altitude
Contains a lot of ozone (ozone layer):
Found in the stratosphere between 10 - 50km above the ground
Protects us from the harmful effects of UV of certain wavelengths
Decrease in ozone concentration Increase in UV-B radiation
reaching the earth surface
The ozone layer
•The ozone layer was discovered
in 1913 by the French physicists
Charles Fabry and Henri Buisson.
•Ozone layer depletion, is simply
the wearing out (reduction) of the
amount of ozone in the
•The ozone layer absorbs 97–99%
of the Sun's medium-frequency
ultraviolet light , which otherwise
would potentially damage
exposed life forms on Earth.
•The ozone layer is being
destroyed by CFCs and other
Ozone formation and depletion
• The movement of O2 from ocean to air that began with
cyanobacteria continues today, as photosynthesis by microorganisms
in the oceans supplies most of the oxygen to the atmosphere.
• As O2 dissolved throughout the atmosphere, solar radiation began to
split O2, which then recombines to form ozone O3.
• Ozone has the unique property of absorbing the frequency of UV that
is the most disruptive to the complex molecules of living organisms.
• Only after the UV was blocked by ozone could more complex living
things begin to use the upper areas of the oceans where there was
• The protective ozone layer and high levels of oxygen allowed complex
life to evolve on the planet.
• Artificial chemicals such as CFCs are depleting the ozone by delivering
chlorine high into the atmosphere where each chlorine atom
destroys thousands of ozone molecules.
Ozone formation and depletion (cont…)
• Chloroflourocarbons (CFCs) are chemicals that were used as propellants in
spray cans, blowing agents to make plastic foam products, and as
• CFCs, aka Freon, is still used in most refrigeration equipment in homes,
offices, cars, and are also used as a cleaning agent in other nations.
• A global agreement is reducing the amount of CFC produced, but other
chemicals also affect ozone, and the CFC already in the atmosphere will be
destroying ozone for decades.
• Not all the effects of ozone depletion can be predicted, but it may directly
produce greater skin cancer and cataracts, and may indirectly affect all
living things on the surface of the planet by making plants sick.
• People can help to protect the ozone layer by making sure that the
refrigerant from their air conditioners and refrigerators is not leaking, that
the Freon is recovered when the machines are serviced, and insist that nonCFC refrigerant be used to recharge the machine or in a new machine, and
that all nations stop using CFCs.
• People can protect themselves from the effects of ozone depletion by using
UV sunblock and avoiding excessive exposure to the sun.
Main uses of ODS
Vehicles (mobile airconditioning systems)
Why is the ozone layer important to life on
• The stratospheric
completely stops the
penetration of UV-C
rays and eliminates
most of the UV-B rays.
• Therefore, the ozone
layer protects life on
Earth from the
harmful effects of
solar radiation on a
Why control Ozone Depleting Substances?
• Harmful to the environment and human health
– Ozone (Layer) depletion
– Climate Change
– Global Warming
– Economic impact
• International agreement for their complete phase out
• National legal obligation for their phase out
• Personal obligation to protect and care for our natural environment
– Our generation
– Our children’s generation
Some Effects of Ozone Layer Depletion
Damages DNA which suppresses immune system resulting in increase in infectious
diseases e.g. , Skin Cancer; Eye Cataracts
Plants & Trees
Reduces crop production, damage to seeds
Reduces quality of crops
Damage to plankton, aquatic plants, fish larvae, shrimp, crabs
Affects marine food chain
degrades paints, rubber, wood, & plastics, especially in tropical regions
Ground Level Smog
Increase in the formation of Ground level ozone as a pollutant
High economic cost
Damages could be in billions of US dollars
So what might life be like without the ozone
The Ozone Hole (cont…)
• An area of the ozone layer where there is very little
• A severe depletion of ozone in a region of the ozone
layer, particularly over Antarctica and over the Arctic.
• Since the 1970’s the ozone hole has been increasing in
size over the Antarctic.
• For the first time, in September of 2000, the ozone hole
became so large it actually left populated areas of
southern Chile fully exposed to the effects of the Sun’s
• The depletion is caused by the destruction of ozone by
CFCs and by other compounds, such as carbon
tetrachloride (CCl4 ) and carbon tetrafluoride (CF 4 ).
Hole in the ozone layer
What can be done?
• Reduce the use of CFCs
• They are already banned in aerosols (1987)
• BUT they are still used as refrigerants
• Recycle fridges and air conditioning plants
The current situation
• The holes developing over the pole suggest that
they may be show an improvement
• BUT CFC molecules take 30 years to rise up to the
• The chlorine radicals last a long time
• The peak ozone damage was supposed to be in
• Damage could go on another 50 years
16 September 1987
1 January 1989 if 11 states have
ratified by then
ratification by 20 states
197 (all United Nations members, as
Niue, the Cook Islands, the Holy See and the
Secretary-General of the United
Arabic, Chinese, English, French,
Russian and Spanish.
Montreal Protocol (cont…)
• An international agreement, signed by most of the
industrialized nations, to substantially reduce the use of
• The Montreal Protocol on Substances that Deplete the
Ozone Layer was designed to reduce the production
and consumption of ozone depleting substances in
order to reduce their abundance in the atmosphere,
and thereby protect the earth’s fragile ozone Layer.
• The protocol set limits on the production of
chlorofluorocarbons (CFCs), halons, and related
substances that release chlorine or bromine to the
ozone layer of the atmosphere.
What Is Being Done to Counter the Effects of Ozone
• Montreal Protocol (adopted in 1987) – panel
of experts was formed to investigate substances
responsible for hole formation
– Established policies that prevent future use of
certain types of chemicals
– Stipulated that the production and consumption of
compounds contributing towards depletion of
ozone in the stratosphere were to be phased out by
the year 2000 (2005 for methylchloroform)
The Environmental Protection Agency (EPA)
• Responsible for enforcing the Montreal
Protocol within the U.S.
– The EPA has several programs in place;
• Regulating and enforcing on-road car and truck airconditioning systems
• Regulating most air-conditioning and refrigeration
• Technician certification
• Service equipment
INDIA’S COMMITMENT TO THE MONTREAL PROTOCOL
19th June 1991 : India became a Party to the Vienna
17th September 1992 : India became a Party to the
Montreal Protocol and ratified the London Amendment.
3rd March 2003 : India ratified Copenhagen Amendment
(1992), Montreal Amendment (1997) and Beijing
November 1993 : India’s Country Programme was
January 2006 : India’s Country Programme was updated.
INSTITUTIONAL FRAMEWORK IN INDIA
Ozone Cell is established under the Ministry of Environment &
Forests for undertaking activities relating to implementation of
Vienna Convention and Montreal Protocol.
Empowered Steering Committee (ESC) has been constituted in the
MOEF with the approval of Cabinet. It is the apex body Chaired by
Secretary (E&F) to take policy decisions and to oversee the overall
implementation of the Montreal Protocol in India.
The following two Standing Committees have also been constituted
set up to provide assistance on specific implementation issues to the
Empowered Steering Committee (ESC) :
1. Technology and Finance Standing Committee.
2. Monitoring and Evaluation Committee.
Signs of Recovery???
There have been some signs of recovery
– 1997 satellite showed a decline of several known ozone-depleting
– Satellite images show some slowing down of ozone loss
Antarctica - Dec. 2005
Recovery is slow
Images of Antarctica Taken Indicate A Slow
Results to date
• The Montreal Protocol is working. There is clear evidence
of a decrease in the atmospheric burden of ozonedepleting substances in the lower atmosphere and in the
• Some early signs of the expected stratospheric ozone
recovery are also evident.
• Furthermore, if the Parties were to eliminate all emissions
of ozone depleting substances soon after 2006, it would
advance by about 15 years (from around 2050 to 2035) the
global ozone layer recovery to pre-1980 levels.
Montreal Protocol provided dual protection:
to Ozone layer and to Climate change
Climate benefits already achieved larger than
Kyoto Protocol targets for 2008-2012
Potential for additional climate benefits
significant compared to Kyoto
Without the Montreal Protocol by 2050
• Ozone depletion would have reached to at least 50 % in the
northern hemisphere’s mid latitudes
• 70% in the southern mid latitudes
• Doubling on the UV-B radiation reaching earth’s surface
• Estimated increases of
– 19 million more cases of non-melanoma cancer
– 1.5 million more cases of melanoma cancer
– 130 million more eye cataracts
• The Montreal Protocol has been called the most
successful international environmental agreement
to date. It has been hailed as an example of
exceptional international co-operation.
• In a 2001 report, NASA found the ozone thinning
over Antarctica had remained the same thickness
for the previous three years.
• The most recent scientific evaluation in the year
2006 of the effects of the Montreal Protocol states,
"The Montreal Protocol is working. There is clear
evidence of a decrease in the atmospheric burden
of ozone depleting substances and some early signs
of stratospheric ozone recovery."
The Former Secretary of the United Nations,
Kofi Annan has been quoted as saying that "perhaps
the single most successful international agreement
to date has been the “Montreal Protocol". It has
been ratified by 196 states.