Significant ideas:
Stratospheric ozone is a key component of the
atmospheric system because it protects living systems
from the negative effects of ultraviolet radiation from
the Sun.
Human activities have disturbed the dynamic
equilibrium of stratospheric ozone formation.
Pollution management strategies are being employed
to conserve stratospheric ozone.
1)
2)
3)
Rowland and Molina's warnings about CFCs and ozone
depletion, followed by the discovery of the ozone hole,
spurred the negotiation of several international agreements
to protect the ozone layer, leading eventually to a worldwide
ban on CFC production in 1996
Big Questions:
•
•
•
To what extent have the solutions emerging form this
topic been directed at preventing environmental
impacts, limiting the extent of the environmental
impacts or restoring systems in which environmental
impacts have already occurred?
How are the issues addressed in this topic of relevance
to sustainability or sustainable development?
In what ways might the solutions explored in this topic
after your predictions for the state of human societies
and the biosphere some decades from now?
Big Questions:
•
•
•
Why has the Montreal Protocol been so successful? Will
it continue to be successful?
Outline the links between stratospheric ozone and
sustainability/sustainable development.
What are the greatest threats to stratospheric ozone
likely to be, and from where, in the decades to come?
Understandings
Statement
Guidance
6.2U1
Some ultraviolet radiation from the Sun is
absorbed by stratospheric ozone causing the
ozone molecule to break apart. Under normal
conditions the ozone molecule will reform. This
ozone destruction and reformation is an example
of a dynamic equilibrium.
The use of chemical symbols, formulae or equations
for the destruction of ozone is not required.
6.2.U2
Ozone depleting substances (including
halogenated organic gases such as
chlorofluorocarbons—CFCs) are used in aerosols,
gas-blown plastics, pesticides, flame retardants
and refrigerants. Halogen atoms (such as
chlorine) from these pollutants increase
destruction of ozone in a repetitive cycle,
allowing more ultraviolet radiation to reach the
Earth.
6.2.U3
Ultraviolet radiation reaching the surface of the
Earth damages human living tissues, increasing
the incidence of cataracts, mutation during cell
division, skin cancer and other subsequent
effects on health.
Understandings
Statement
6.2U4
The effects of increased ultraviolet radiation on
biological productivity include damage to
photosynthetic organisms, especially
phytoplankton, which form the basis of aquatic
food webs..
6.2.U5
Pollution management may be achieved by
reducing the manufacture and release of ozonedepleting substances. Methods for this reduction
include: recycling refrigerants, developing
alternatives to gas-blown plastics, halogenated
pesticides, propellants and aerosols, developing
non-propellant alternatives.
6.2.U6
UNEP has had a key role in providing
information, and creating and evaluating
international agreements, for the protection of
stratospheric ozone.
6.2.U7
An illegal market for ozone-depleting substances
persists and requires consistent monitoring.
Guidance
Understandings
Statement
6.2U8
The Montreal Protocol on Substances that
Deplete the Ozone Layer (1987) and subsequent
updates is an international agreement for the
reduction of use of ozone-depleting substances
signed under the direction of UNEP. National
governments complying with the agreement
made national laws and regulations to decrease
the consumption and production of halogenated
organic gases such as chlorofluorocarbons (CFCs).
6.2.U9
Pollution management may be achieved by
reducing the manufacture and release of ozonedepleting substances. Methods for this reduction
include: recycling refrigerants, developing
alternatives to gas-blown plastics, halogenated
pesticides, propellants and aerosols, developing
non-propellant alternatives.
Guidance
Applications and Skills
Statement
6.2.A1
Evaluate the role of national and international
organizations in reducing the emissions of ozonedepleting substances.
Guidance
Stratospheric ozone is a key component of the atmospheric
system because it protects living systems from the negative
effects of ultraviolet radiation from the Sun
• What issues have you heard regarding the ozone layer?
https://geekswipe.net/research/nature/ozone-layer-will-take-50-years-to-recover-2070/
Stratospheric ozone is a key component of the atmospheric
system because it protects living systems from the negative
effects of ultraviolet radiation from the Sun
• During the Cambrian Explosion, many complex multicellular
organisms evolved in the oceans,
• Marine organisms became mobile and were able to live in
shallower areas of the ocean with greater sunlight exposure.
• Around 420 million years ago, ozone levels were high enough to
allow for organisms to survive on land, without any shielding from
water
https://earthhow.com/proterozoic-eon/
6.2.U1 Some ultraviolet radiation from the Sun is absorbed by
stratospheric ozone causing the ozone molecule to break apart.
Under normal conditions the ozone molecule will reform. This
ozone destruction and reformation is an example of a dynamic
equilibrium.
Allows UVa and UVb through, but blocks UVc waves
• UVa - causes wrinkles
• UVb - causes skin cancer
• UVc - worst one because of
damage to organisms/tissues
https://scied.ucar.edu/ozone-layer
6.2.U1 Some ultraviolet radiation from the Sun is absorbed by
stratospheric ozone causing the ozone molecule to break apart.
Under normal conditions the ozone molecule will reform. This
ozone destruction and reformation is an example of a dynamic
equilibrium.
• Some ultraviolet radiation
from the Sun is absorbed
by stratospheric ozone
causing the ozone
molecules to break apart
O2 + O + UV → O3
the energy provided by incoming UV light changes O2 → O3
http://www.theozonehole.com/ozonecreation.htm
6.2.U1 Some ultraviolet radiation from the Sun is absorbed by
stratospheric ozone causing the ozone molecule to break apart.
Under normal conditions the ozone molecule will reform. This
ozone destruction and reformation is an example of a dynamic
equilibrium.
• Under normal conditions
the ozone molecule will
reform.
• This ozone destruction
and reformation is an
example of a dynamic
equilibrium
https://en.wikipedia.org/wiki/Ozone_layer
Click image for more information on
ozone production
Evaluate the diurnal fluctiation of atmospheric ozone
6.2.U2 Ozone depleting substances (in clouding halogenated
organic gases such as chlorofluorocarbons-CFCs) are used in
aerosols, gas-blown plastics, pesticides, flame retardants and
refrigerants. Halogen atoms (such as chlorine) from these
pollutants increase destruction of ozone in a repetitive cycle,
allowing more ultraviolet radiation to reach the Earth
• How ozone is depleted by CFC’s:
Click on the image to watch a video on ozone depletion
6.2.U2 Ozone depleting substances (in clouding halogenated
organic gases such as chlorofluorocarbons-CFCs) are used in
aerosols, gas-blown plastics, pesticides, flame retardants and
refrigerants. Halogen atoms (such as chlorine) from these
pollutants increase destruction of ozone in a repetitive cycle,
allowing more ultraviolet radiation to reach the Earth
Click on the image to watch a video on ozone depletion
Human activities have disturbed the dynamic equilibrium of
stratospheric ozone formation
There are two
important things to
remember here
1. The 1-2-3
sequence
outlined at right
2. The class of
ozone-depleting
chemicals at the
center bottom
6.1U3 Ultraviolet radiation reaching the surface of the Earth
damages human living tissues increasing the incidence of
cataracts, mutations during cell division, skin cancer and other
subsequent effects on health
https://www.gayaopticians.com/uv-an-invisible-danger/
6.1U3 Ultraviolet radiation reaching the surface of the Earth
damages human living tissues increasing the incidence of
cataracts, mutations during cell division, skin cancer and other
subsequent effects on health
• DNA readily absorbs
UV-B radiation, which
commonly changes the
shape of the molecule
• Changes often mean
that protein-building
enzymes cannot “read”
the DNA code at that
point on the molecule.
• As a result, distorted
proteins can be made,
or cells can die.
https://earthobservatory.nasa.gov/features/UVB
6.1U3 Ultraviolet radiation reaching the surface of the Earth
damages human living tissues increasing the incidence of
cataracts, mutations during cell division, skin cancer and other
subsequent effects on health
https://freeness.us/gel-manicures-linked-to-skin-cancer/
6.1U3 Ultraviolet radiation reaching the surface of the Earth
damages human living tissues increasing the incidence of
cataracts, mutations during cell division, skin cancer and other
subsequent effects on health
Beneficial Effects of UV
• In animals stimulates the production of Vit D.
• Treat psoriasis and vitiligo (skin diseases)
• Steriliser, water purifier
• Forensics, lighting, lasers
6.1U3 Ultraviolet radiation reaching the surface of the Earth
damages human living tissues increasing the incidence of
cataracts, mutations during cell division, skin cancer and other
subsequent effects on health
Take care not to confuse effects of ozone decline in the stratosphere
(i.e. increase in UV radiation reaching the earth) with impacts of ozone
in the troposphere.
6.2.U4 The effects of increased ultraviolet radiation on biological
productivity include damage to photosynthetic organisms,
especially phytoplankton which form the basis of aquatic food
webs
• Phytoplankton do not
exist in isolation
• Other microbes, the
protozoa, bacteria and
viruses, can be directly
damaged or killed by solar
UVB.
• Due to the interactions
between trophic levels of
the microbial community,
any UVB-induced impact
at one level can alter the
entire community
http://www.antarctica.gov.au/magazine/2001-2005/issue-1-autumn-2001/science/effect-ofozone-depletion-on-antarctic-marine-microbes
6.2.U4 The effects of increased ultraviolet radiation on biological
productivity include damage to photosynthetic organisms,
especially phytoplankton which form the basis of aquatic food
webs
• Plants are vulnerable to increased UV-B radiation because many
cellular components can absorb UV directly
• Increased UV-B radiation has many effects on plant morphology,
physiology and development, and its impacts on growth and
development
• Reduction in biomass accumulation due to UV-B exposure has been
verified
• Many plants exposed to this radiation exhibit decreased rates of
photosynthesis
6.2U6 UNEP has had a key role in providing information and
creating and evaluating international agreements, for the
protection of stratospheric ozone.
International Agreements
• The United Nations (UN) was instrumental in establishing binding
legislation to encourage countries to reduce damage to the ozone
layer.
• Vienna Convention in 1985
• Montreal Protocol in 1987.
• In 2009, it became the first
UN treaty to be ratified by
all 197 nations.
6.2.U8 The Montreal Protocol on Substances that Deplete the
Ozone Layer (1987) and subsequent updates is an international
agreement for the reduction of use of ozone-depleting substances
signed under the direction of UNEP. National governments
complying with the agreement made national laws and regulations
to decrease the consumption and production of halogenated
organic gases such as chlorofluorocarbons (CFCs)
Progress
Implementation of the Montreal Protocol has resulted most of the main
ODS to be banned with some exceptions for medical and research use.
• CFCs production has stopped and are resulting in atmospheric levels
stabilizing or declining.
• Production of halons has stopped, but atmospheric levels continue to
rise, possibly due to emissions from old fire extinguishers.
Adoption and performance of the Montreal Protocol reporting the cumulative
number of countries ratifying the Montreal Protocol, area of the ozone hole, and
production of CFCs.
http://ozone.unep.org/new_site/en/index.php; http://ozonewatch.gsfc.nasa.gov/.
6.2.A1 Evaluate the role of national and international oganizations
in reducing the emissions of ozone-depleting substances
Why is the Montreal
Protocol regarded as one of
the most successful
international environmental
agreements in history?
Justify your response with
evidence, named examples,
and/or specific case studies
http://www.theozonehole.com/dualbenefits.htm
6.2.A1 Evaluate the role of national and international oganizations
in reducing the emissions of ozone-depleting substances
Watch the following video by UNEP which provides a summary
of some the key issues of stratospheric ozone depletion.
Answer the questions on the study guide
6.2.A1 Evaluate the role of national and international oganizations
in reducing the emissions of ozone-depleting substances
HFC Kigali Amendment to the Montreal
Protocol – 2019
• HFCs harm the atmosphere
• environmental issues need to be
addressed at an intergovernmental
level;
• changes in behavior
• MEDCs agreed to provide financial
assistance LEDCs;
• technological development has found
alternatives to HFCs;
6.2.A1 Evaluate the role of national and international oganizations
in reducing the emissions of ozone-depleting substances
• Your response must include named
references to both national
organizations and international
organizations involved in the
reduction of ozone-depleting
emissions.
• Remember that evaluate means
weighing the pros and cons and
make a determination as to which
are more significant
Click on the logo to get a history of the Montreal Protocol
https://sgerendask.com/en/short-history-of-the-montreal-protocol-and-holes-in-the-ozone-layer/
6.2.A1 Evaluate the role of national and international oganizations
in reducing the emissions of ozone-depleting substances
Watch the following video Explain how the Kigali Accord supports the
protection of the ozone layer and takes action against climate change
6.2.U7 An illegal market for ozone-depleting substances persists
and requires consistent monitoring
Challenges
Click on the image to watch a video on “Someone in East Asia is Damaging
the Ozone Layer”
https://www.bloomberg.com/news/articles/1997-07-06/the-black-market-vs-dot-the-ozone
6.2.U7 An illegal market for ozone-depleting substances persists
and requires consistent monitoring
Challenges
• Long life span of ODS
• ODS present in discarded equipment
• Lack of alternatives
• Replacement chemicals also ODS
• Lack of policing and enforcement
• Illegal markets
http://www.sviva.gov.il/English/env_topics/InternationalCooperation/IntlConventions/Pa
ges/ViennaConvention.aspx
6.2.U7 An illegal market for ozone-depleting substances persists
and requires consistent monitoring
Challenges
• CFC emissions should have
followed the blue trend line,
according to numbers
reported to the UN
• However two different
monitoring methods (red
and orange trend lines)
show that CFC emissions
started to rise again in 2012
https://gosint.wordpress.com/2018/05/18/the-rise-of-the-cfc-an-atmospheric-spythriller/
6.2.U7 An illegal market for ozone-depleting substances persists
and requires consistent monitoring
Challenges
• Data points indicate the
source is north of the
equator and somewhere
in eastern Asia
https://gosint.wordpress.com/2018/05/18/the-rise-of-the-cfc-an-atmospheric-spythriller/
6.2U5 Pollution management may be achieved by reducing the
manufacture and release of ozone-depleting substances. Methods
for this reduction include:
From most effective strategy to the least
effective:
• Tier 1: Campaign to educate public
and pressure, industry to find and
use suitable replacement
• Tier 2: Policing and enforcement to
ensure compliance, recover and
recycle CFC’s from refrigerators and
AC units
• Tier 3: Remove and destruction of
ozone-depleting compounds
https://www.agasamericas.com/products-services/refrigerants/
6.2U5 Pollution management may be achieved by reducing the
manufacture and release of ozone-depleting substances. Methods
for this reduction include:
Evaluate – weight the pros and cons, then reach conclusions about which
are more significant
• Think of it as a cost benefit analysis
• How is each intervention level
successful?
• What hinders the success of each
intervention level?
• Which level is likely to be the most
effective and feasible to implement?
• Justify your conclusion with reasons
and evidence