[] TL: UPDATE BRIEFING ON OZONE DEPLETION, UV-B AND SKIN CANCER
(GP)
SO: Greenpeace UK, (GP)
DT: June 1993
Keywords: environment ozone atmosphere uk europe health cancer
uk europe /

CANONBURY VILLAS, LONDON N1 2PN
TEL: 071-354 5100
TELEX: 25245 GPEACEG * FAX: 071-696 0012/ 071-696 0014

What effect could ozone depletion have on the world?

Ozone acts as a shield from the worst of the damaging UV-B
radiation emitted by the sun. UV-B can damage cells of living
organisms, causing then to die (if levels are very high) or
malfunction in some way. There is always some UV-B that gets
through the ozone shield, and causes sunburn for instance, but
as ozone is depleted over the coming decade or so we can expect
to see increases in the levels of UV-B radiation reaching the
earth's surface. 

Ozone depletion, as a result of pollution of the stratosphere
with chemicals such as CFCs, has been increasing alarmingly in
recent years in an unpredictable manner. Plants, marine
ecosystems and humans are all at risk. 

What effects could increased levels of UV-B have on humans? 

UV-B can cause non-melanoma skin cancer (NMSC) in humans. As
ozone is depleted and UV-B levels rise as is expected, we can
expect to see an increase in the incidence of NMSC depending on
the extent of ozone depletion. It has been estimated that for
every one percent depletion in ozone there will be a 2-3%
increase in the incidence of NMSC. 

UV-B probably plays a role in causing melanoma skin cancer (the
more dangerous form), may cause some types of eye cataract and
harm the immune system. It is more difficult to put numbers on
the likely increases of these conditions or determine their
effects because their relationship with exposure to sunlight is
more complex and difficult to model. 

Have levels of skin cancer already increased because of ozone
depletion? 

Not yet, but ozone depletion over the highly populated areas of
the northern hemisphere is set to worsen considerably over the
next decade. It is during that decade and the decades which
follow until ozone levels return to normal, when people are
expected to be exposed to an increasing level of UV-Bs which
should then decline as ozone increases. 

There will also be a 'lag' period before cases of skin cancer as
a result of ozone depletion arise. The peak incidence of cases
of NMSC as a result of increases of UV-B following ozone
depletion is not expected until 2040, around 35 years after the
time when ozone depletion will have been at its maximum.


It has only been over the past few years that significant ozone
depletion has been detected over the more populated regions of
the world. Before that time ozone depletion had been considered
to be mainly a problem for Antarctica where the ozone 'hole'
occurs each spring. 

Levels of skin cancer have been increasing dramatically in
recent years, isn't this because of ozone depletion? 

No. The increases which have been seen in skin cancer have been
due to changes in people's lifestyle. People have been keen to
get a tan and have more leisure time than in the past. Therefore
they spend more time outdoors with less clothes on than they
did. The high levels of skin cancer being seen now are the
reflection of past behaviour. Ozone depletion is adding to the
future risk. 

We wouldn't have expected to see increases in skin cancer due to
ozone depletion yet, because there is a time lag between
exposure and developing cancer, and because it is the future
decades when we will be at increasing risk. 

It is children alive today and those born over the next 2
decades who will face the consequences of ozone depletion in the
future. Because children spend a lot of time out of doors, it is
more likely that their lifetime risk of developing NMSC will
increase than for an adult alive today. 

Is it possible to protect against the effects of UV-B? 

Yes, it's quite easy for people. The same measures which should
always be taken against the harmful effects of the sun will also
protect against rises in UV-B as a result of ozone depletion in
the future. So especially in the summer, it is important to
cover up - wear a hat, long sleeved shirt or blouse and wear
sunscreen on those areas you can't cover up. 

Have levels of UV-B already begun to increase as a result of
ozone depletion? 

Yes, but it depends where you are. For instance, in Antarctica
there have been 5-fold increases in UV-B when the ozone hole
occurs. There have also been increases in UV-B recorded in
Australia, New Zealand and South America.   

In the northern hemisphere the picture is more complex because
low level pollution with ozone can absorb UV-B and hide any
increase in UV-B. So in many populated regions there has been no
clear evidence of an increase in UV-B, and in some areas UV-B
seems to have decreased. However, in the Alps for instance,
where the air is clean, there has been a downward trend in UV-B
over the past few years. 

As ozone depletion progresses, there is every expectation that
levels of UV-B will-inevitably rise. 


What is happening to UV-B in the UK? 

Recording of UV-B has only been undertaken by the NPRB since
1988 and so there is no really reliable baseline from which to
detect trends of UV-B, especially as there is considerable
natural variation due to clouds, the influence of pollutants
like low level (tropospheric) ozone and season. Measuring UV-B
is also quite difficult and in the first couple of years there
were problems with the monitoring system. There are only 3 sites
where UV-B is measured by the NRPB so monitoring is not
comprehensive. 

It may take some time, therefore, to detect a trend. And
ancillary data on tropospheric ozone is also needed to be able
to interpret any data. 

Could low level ozone effectively protect us against rises in
UV-B? 

Depending on tropospheric ozone, which is a pollutant and
harmful to humans and plant life at low concentrations, to
protect against UV-B is like treating the symptoms of one poison
with another. Ozone produced at ground level cannot move up to
the stratosphere to replace ozone lost there. The most sensible
course of action is to take steps to ensure that the production,
use and release of ozone depleting substances is stopped and the
production of ozone as a pollutant at ground level is prevented.


THE IMPACTS OF OZONE DEPLETION

Presentation by Jan Sinclair
Greenpeace International

Chlorine-Free Great Lakes: local action for a global solution
Monroe, Michigan
December 5 1992

OZONE DEPLETION: DESTROYING LIFE'S PROTECTION

The ozone layer acts as a protective shield, filtering out
radiation from the sun that threatens the health and even the
survival of all forms of life on Earth. Now, however, man-made
chemicals are destroying this protection, with alarming
consequences. 

Ozone depletion is already damaging a variety of forms of life
on Earth. This damage will worsen for at least another decade,
because of the long lifetimes of the chlorine chemicals that
catalyze ozone destruction. The ozone layer will not heal for a
much longer period of time, because of the huge quantities of
long-lived chlorine chemicals either already in the
stratosphere, or making their way up there. It may take almost
a hundred years before levels of chlorine in the stratosphere
have dropped below those at which the Antarctic ozone hole first
began to appear. No form of life is exempt from these impacts.
The extra ultraviolet radiation allowed through a depleting
ozone layer harms plants, animals, birds, humans and life in the
oceans. 

EFFECT ON HUMANS: IMMUNE SYSTEMS AND VACCINATION PROGRAMS

Ultraviolet radiation profoundly affects the immune system, and
particularly the system of immunity-producing cells directly
beneath the layer of our skin - often the body's first line of
defence against infection. Normally a vaccine injected into the
skin triggers an immune response, instructing the body to
produce antibodies to fight the disease in question. However,
when skin has been over-exposed to ultraviolet radiation, this
system breaks down. The body then fails to recognize that the
vaccine being injected is an enemy that requires defences.
Instead, it treats the vaccine as the same sort of friend as the
body's own enzymes. 

This effect of ozone depletion clearly has serious implications
not only for the development of skin cancers, but also for many
infectious diseases - including the speed with which HIV-
positive virus is activated into full-blown AIDS. 

The consequences for developing countries are also deeply
worrying. In many of these countries, the control of infections
such as measles depends on effective immunization. The United
Nations Environment Programme (UNEP) has warned that many
diseases could be affected by this suppression of immune
systems. At the very least, these include all diseases that have
a stage involving the skin - such as measles, chicken pox,
herpes, malaria, tuberculosis and leprosy. 

SKIN CANCER

Excessive exposure to the biologically damaging form of
ultraviolet radiation (UV-B) allowed through a depleting ozone
layer is known to cause skin cancer. In addition, because UV-B
suppresses the skin's immune responses, the body's immune system
is less likely to reject a growing tumor. UNEP medical experts
have calculated that a sustained 10 percent global ozone
depletion would result in a 26 percent increase in non-melanoma
skin cancer cases world-wide, affecting more than 300,000
people, with a further 4500 cases of melanoma. The UNEP experts
warned that this prediction may be "extremely conservative...
possibly off by a factor of two or more". 

Global ozone depletion is already running at almost 6 percent,
and rising. It is now affecting heavily-populated mid-latitude
regions of the world, with winter depletion above the United
States and Europe running at 15 to 20 percent. The US
Environmental Protection Agency has concluded that every 1
percent decrease in stratospheric ozone could mean an extra 2
percent of the world's population - more than 100 million people
- developing another form of skin cancer - cutaneous malignant
melanoma - and an extra 10 - 15 million dying as a result. 

EYE DAMAGE

As the ozone layer thins, cataracts and blindness are expected
to increase. Unlike the skin, which can partially adapt to UV-B
by becoming thicker and browner, the eye has no such protection.
Rather, eyes become more sensitive the more they are exposed to
ultraviolet radiation. 

The first symptom of excessive exposure to UV-B is the condition
of photokeratitis or snow blindness, in which the front of the
eye, the eyelids and the skin around the eyes redden. Further
exposure can cause cataracts, which already are the single
largest cause of blindness world-wide. In 1985 the World Health
Organization estimated that cataracts were responsible for some
17 million cases of blindness - more than half the global total.
UNEP has estimated that for every 1 percent depletion of the
ozone layer, we can expect an extra 100,000 to 150,000 cases of
blindness. Further, its experts say a 10 percent sustained ozone
depletion would mean an extra 1.75 million cataracts worldwide
each year. 

IMPACTS ON ANIMALS AND BIRDS

All the impacts on humans can be expected to affect animals and
birds as well. While fur, hair and feathers offer greater
protection against skin cancer, exposed parts such as eyes and
lips will still be vulnerable to skin cancer. Moreover, while
humans can protect against the ravages of excessive UV-B by
wearing sunscreen, covering up with long sleeves and trousers or
skirts, and wearing sunglasses and hats, this is not an option
available to birds and animals. 

IMPACTS ON THE OCEANS. 

Ozone depletion is already affecting the very base of the marine
food web. Phytoplankton, the tiny marine organisms that form the
first step of the oceanic food chain, are highly sensitive to
ultraviolet radiation, because they lack the protective outer
layers of higher forms of plants and animals. Beneath the
Antarctic ozone hole, scientists have measured losses of
phytoplankton averaging 6 - 12 percent, with 25 percent
reductions in some cases. The seriousness of this recorded
impact cannot be overestimated. The Southern Ocean contains a
huge proportion of global quantities of phytoplankton. Their
concentrations in sub-polar waters may be 1000 to 10,000 greater
than in tropical and sub-tropical waters. 

Even slightly increased doses of UV-B reduce the amount of food
which phytoplankton create through photosynthesis. And even a
small loss of this basic food source would dramatically affect
the intricate marine ecosystem, with serious knock-on effects
for global food supply. 


Zooplankton feed off phytoplankton and form the second stage of
the marine food web. They are also highly sensitive to increased
UV-B radiation. UNEP has reported that if ozone depletion
reached 15 percent over temperate waters, it would take less
than five days in summer for half the zooplankton in the top
meter of these waters to die from the increased radiation. 

UV-B also damages juvenile forms of fish, shrimp, crab larvae
and other small animals in the oceans. The ability of food fish
larvae to reproduce, grow and survive diminishes as ultraviolet
radiation increases. UNEP has also reported that on the North
American Pacific coastal shelf at the height of summer, a 16
percent reduction in ozone would kill 50 percent, 82 percent and
100 percent of anchovy larvae aged 2, 4, and 12 days
respectively. 

Extra amounts of ultraviolet radiation reaching the oceans - and
this radiation penetrates more than 60 meters below the surface
of the oceans - could also dramatically change species
composition, further disrupting the marine food web. 

The damaging effects of UV-B on phytoplankton also has serious
implications for the scale of the threat of global warming. The
oceans are responsible for absorbing up to half the carbon
dioxide in the atmosphere, and phytoplankton play by far the
greatest role in this oceanic absorption. Any reduction in this
carbon-fixing activity would undoubtedly affect global warming
by allowing large quantities of carbon dioxide to remain in the
atmosphere. UNEP has calculated that a 10 percent decrease in
carbon dioxide uptake by the oceans would leave about the same
amount of carbon dioxide in the atmosphere as is produced by
fossil fuel burning. 

IMPACTS ON LAND PLANTS

Increased amounts of ultraviolet radiation inhibits germination
rates, stunts plant growth, and can adversely affect
photosynthetic activity, transpiration rates and flowering. It
can also affect the timing of flowering, which could have far-
reaching effects if insect-pollinated plants start flowering
earlier or later than the appearance of their natural insect
pollinators. 

When the increasing amount of toxic pollution is added to the
stress of extra UV-B radiation, the overall harmful effect on
plants increases substantially. In addition, certain plant
diseases can become more severe when the plants are exposed to
excessive amounts of ultraviolet radiation. 

Rice production seems likely to be drastically affected by ozone
depletion. The tiny organisms such as cyanobacteria which supply
natural nitrogen fertilizer to rice paddies are highly sensitive
to UV-B. As increasing amounts of radiation reach the Earth's
surface, it is expected that this natural nitrogen supply will
be significantly reduced. 

This impact will hit developing nations particularly hard. These
nations have little money available for artificial nitrogen
fertilizers. Even before the harmful effects of artificial
nitrogen on global warming and soil and water pollution are
considered, there simply would not be enough artificial nitrogen
available in any case. It has been estimated that cyanobacteria
produce some 35 million tonnes of nitrogen each year, compared
with an annual global production of 30 million tonnes of
artificial nitrogen. 

Yields of many other crops are expected to drop as well. While
only a few studies have been made under realistic ultraviolet
conditions, the results from these studies suggest that global
agricultural yield is potentially at risk as ozone depletion
continues. Significant yield reductions of up to 25 percent for
a 25 percent ozone depletion have been found in several soybean
cultivars. Food quality also drops, because excessive UV-B
reduces the protein and oil content of seeds. In a trial of 10
crop species, half the species showed yield reductions of
between 5 percent and 90 percent. Wheat yields dropped by 5
percent, potato yields by 21 percent and squash by 90 percent. 

INCREASED AIR POLLUTION

Extra quantities of ultraviolet radiation reaching the lower
atmosphere will speed up the chemical reactivity of the
troposphere, creating more smog and acid rain in both urban and
rural areas. UNEP has warned that while this problem will be
worst in heavily polluted urban areas with few emission
controls, even urban areas with extensive air pollution
regulations will be affected. 

Ozone depletion is expected to spark significant increases in
acid rain for another reason as well. The extra ultraviolet
radiation reaching the lower atmosphere is expected to cause
global increases in atmospheric hydrogen peroxide. This is the
principal chemical that oxidizes sulphur dioxide to form
sulfuric acid in cloud water, making it an important part of
acid rain formation. 

In addition, it now seems at least possible that the rate and
number of chemical reactions caused by increased UV-B radiation
could generate higher concentrations of solid particles in the
atmosphere - and it is known that when these particles reach the
lower stratosphere where the ozone layer lies, they provide a
surface for the kind of large-scale destruction of ozone at
present observed only above Antarctica and the Arctic.
Consequently, heavily polluted areas could find ozone depletion
approaching the level of mini ozone holes above them as the
polluting particles spark even greater ozone destruction in the
stratosphere immediately overhead. 

DAMAGE TO MATERIALS


The increasing amounts of ultraviolet radiation reaching the
Earth's surface will cause many materials to degrade more
rapidly. These materials include rubber products, plastics,
paints and coatings, wood, paper and textiles. Polyvinyl
chloride, polyurethane, polypropylene and other composites used
in aircraft construction will not last as long. Nylon,
polyethylene and polypropylene fishing nets, ropes and sacks
will deteriorate faster, as will vessel hulls made of
unsaturated reinforced polyester. 

FUTURE DANGER

Chlorofluorocarbons (CFCs) and other chlorine and bromine based
chemicals are highly stable substances. Because they do not
break down easily they survive intact in the atmosphere for
decades and even centuries, making their way inexorably up to
the stratosphere where the ozone layer lies. Once there, they
finally begin to disintegrate, releasing their chlorine and
sparking off a chain reaction in which chlorine tears apart
ozone molecules and then re-forms to break down more and more
ozone molecules. Under the right conditions, one chlorine
molecule can destroy 100,000 ozone molecules. 

This damage is not just theoretical. Large-scale destruction of
the ozone layer is already well under way, and not just above
Antarctica. Ozone depletion is also accelerating above mid-
latitudes - above highly populated regions of north America and
northern Europe. Currently, this mid-latitude depletion is
running at twice the rate predicted by scientists. It is now
known that an ozone hole will inevitably form above the Arctic
during some northern Springs - probably, scientists believe,
before the end of this decade. 

In fact, such a hole did form for three days last February, when
Scandinavian scientists measured 50 percent depletion above
Northern Europe. It is important to bear in mind that for every
one percent ozone depletion, on average two percent extra
ultraviolet radiation makes its way to the surface of the
planet. 

The risks are alarming. So far, the history of ozone depletion
has been a history of ozone depletion consistently outstripping
scientific predictions. Science did not predict the formation of
the Antarctic ozone hole. It did not predict the extent of mid-
latitude depletion now being recorded; nor did it predict Arctic
ozone losses of 20 percent, recorded in early 1992. There is no
guarantee that ozone depletion will not spring any more
unpleasant surprises. Given the past record, the reverse is more
likely. 

Yet rather than acting aggressively to immediately ban any
further production and emission of ozone-destroying chemicals,
industry and governments alike are moving as slowly as possible,
with an eye to the survival of every last drop of industry's
profits, rather than to the survival of life itself. CFCs will
not be phased out officially till January 1 1996, and even then,
there are enough loopholes in the Montreal Protocol
international treaty to permit their continued and large-scale
production for at least another decade. 

Worse, industry has persuaded the world's leaders to accept the
long-term production of a new class of ozone-destroyers:
hydrochlorofluorocarbons (HCFCs). 

We already know that because of slow phase-outs and the long
lifetimes of CFCs, we are committed to loading the stratosphere
with 20 percent more chlorine before international agreements
begin to bite. We also know that there are thresholds of
chlorine concentrations, past which exponential ozone depletion
occurs, such as the formation of the Antarctic ozone hole. And
we know that the millions of tonnes of HCFCs which governments
and industry have just agreed can be produced annually for the
next thirty years will wreak their damage on the ozone layer
during the period of extreme risk in the next couple of decades,
when levels of chlorine in the stratosphere reach their highest
peak. 

For the sake of the health and future of all of life on Earth,
Greenpeace demands an immediate ban on all substances which
destroy ozone. 

REFERENCES: 

United Nations Environment Programme (UNEP): Environmental
Effects of Ozone Depletion, 1989, 1991 update 

United Nations Environment Programme / Global Environment
Monitoring System (UNEP/GEMS): The Impacts of Ozone-Layer
Depletion, 1992 

World Meteorological Organization (WMO): Scientific Assessment
of Stratospheric Ozone, 1988, 1991

National Aeronautics and Space Administration (NASA) press
release 30 April 1992

European Arctic Stratospheric Ozone Expedition (EASOE) and
Airborne Arctic Stratospheric Expedition (AASE II) 

International Union for the Conservation of Nature (IUCN): A
strategy for Antarctic Conservation, 1991

Smith, R.C., Prezelin et al: Science 265: 952-959, 1992: Ozone
Depletion: Ultraviolet radiation and phytoplankton biology in
Antarctic waters