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Transcript
Environmental Effects Assessment Panel
EEAP
8th ORM,
Geneve
Influences of Ozone Layer Depletion
and Climate Change on UV-radiation:
Impacts on Human Health and the
Environment
Janet F. Bornman and Nigel D. Paul, co-chairs
Stratospheric
chemistry, climate
Depletion of stratospheric ozone (O3)
UV-B radiation
O3 depleting substances
EEAP
Human
health
ODS applications,
substitutes
Ecosystem
health and
services
Air
Quality
Materials
Environmental Effects Assessment Panel
EEAP
The role of the Environmental Effects
Assessment Panel
Effects of ozone
depletion
Effects of
climate change
Consequences for life on Earth
Environmental Effects Assessment Panel
EEAP
KEY FOCUS AREAS
(Full Assessment Report 2010)
UV changes in relation to impacts:
Human health
Terrestrial ecosystems
Aquatic ecosystems
Carbon and other global chemical cycles
Air quality
Materials
INTERACTIONS
Ozone depletion, climate change, UV radiation
Ozone depletion, climate change, UV
radiation
KEY OUTPUTS
Assessment of future predictions of the effects of
O3, clouds & aerosols for:
UV-B radiation causing
sun-burn
UV-B radiation
involved in human
vitamin D production
Ecosystems, construction materials
*UV-B radiation, 280-315 nm
Environmental Effects Assessment Panel
Ozone depletion, climate change, UV
radiation
Current UV-B radiation compared with 1980
Measurable effects of ozone depletion but also large
variability in UV-B radiation due to clouds & aerosols
Southern Hemisphere cloudier overall than corresponding
Northern Hemisphere (global satellite data)
At mid-latitudes: increases
in UV-B radiation by ca 5%
At high latitudes (areas of
large O3 depletion): large
increases in UV-B radiation
Sufficient to cause sunburn
Environmental Effects Assessment Panel
Ozone depletion, climate change, UV
radiation
Projected future changes in UV: ozone and clouds
At high latitudes: cloud
cover increases (by ca 5%)
At low latitudes (near the
equator): cloud cover
decreases by ca 3%
Reduction of UV radiation
(UV already low)
Increase in UV radiation
(UV already high)
Less easy to achieve
exposure times needed to
produce sufficient vitamin D
Greater risk of sun-burn:
additional increase in
sunburning-UV of 3 to 6%
Environmental Effects Assessment Panel
The Montreal Protocol has PREVENTED
large increases in sun-burning UV
Total chlorine (ppbv)
O3 (DU)
Maximum UV Index
1980
2
310
10
2020
11.5
250
12.5
2040
20
220
15
2065
40
100
30
UV Index: an estimation of the UV important for damage to human skin
Reference future
calculated using
observed & currently
predicted chlorine
concentrations
Environmental Effects Assessment Panel
Human health
KEY OUTPUTS
Assessment of the effects of UV radiation, and
interactions with other environmental change,
on human health, including:
Immune
responses
Skin and eye
diseases (especially
cancers)
Environmental Effects Assessment Panel
Vitamin D
production
Human health
Exposure to sunburning UV-B radiation is a major
environmental risk for skin cancers
M. Norval
Squamous
cell
carcinoma
Basal cell
carcinoma
Non-melanoma
Cutaneous
malignant
melanoma
The Montreal Protocol
has PREVENTED
large increases in skin
cancers that would have
resulted from
uncontrolled ozone
depletion
ALTHOUGH incidence
currently is high
Environmental Effects Assessment Panel
Malignant melanoma of the eye
Most common eye cancer in adults and
may be a link between its incidence and
UV-B radiation
A. Cullen
UV-induced allergy
Occurs in ca 5-20% of the population
often after first spring/summer exposure
to UV radiation
S. Ibbotson
Human health
UV-induced immune-suppression
Complex effect but increased UV exposure may have
significant effects on infectious diseases and auto-immune
diseases
Environmental Effects Assessment Panel
Human health
Need to balance the risks of over-exposure to UV radiation
with the potential beneficial effects
Importance of vitamin D
Vitamin D is produced in the skin following UV-B irradiation
May decrease risk of:
Supports
bone health
- several internal cancers
- autoimmune & infectious diseases
- cardiovascular diseases
Effectiveness of oral vitamin D supplements, and the health
effects of very high vitamin D status are both unclear
Environmental Effects Assessment Panel
Human health
Solar UV-B at midhigh latitudes are
below that required
for adequate Vitamin
D synthesis from
Autumn-Spring
Balance between sun-burning UV-B radiation and that
needed for vitamin-D, and the effects of future environment
change remain unclear
Human health
Combined effects of climate change & solar UV
radiation
• Higher temperatures may lead to more skin cancers
• For the same UV exposure, for every 10oC increase, there
is an estimated 3-6% increase in skin cancers
Several indications of further interactions
• Increase in certain infectious diseases (malaria, Lyme)
• Increase in allergic diseases
• Suppression of the immune response to disease
• Increased photosensitivity of the skin (temp., dust -deserts)
Environmental Effects Assessment Panel
Terrestrial ecosystems
KEY OUTPUTS
Assessment of effects of ozone depletion since
1980 on current plant productivity
Assessment of the effects of future changes in
UV radiation, and interactions with other
environmental change on:
Food security &
food quality
Ecosystem responses to UV
radiation & climate
Environmental Effects Assessment Panel
Terrestrial ecosystems
Plant growth has been reduced by ca 6% in response to
increased UV radiation in areas of significant ozone
depletion
Growth reductions are due to direct damage plus diversion of
plant resources towards protection and repair
• Green
• Loss of green
pigment used
for energy
capture &
growth
pigment
• Reduced
growth
+ UV
- UV
Terrestrial ecosystems
Plant growth has been reduced by ca 6% in response to
increased UV radiation in areas of significant ozone
depletion
-
long-term effects of reduced plant growth may be
important for potential carbon capture/retention
-
Interactions with other components of climate
change
Terrestrial ecosystems
Combined effects of predicted climate change & UV
radiation: plants and ecosystems
- Increasing temperature, rainfall
leads to spread of plant pests
- Increased UV-B radiation: large
effects on plant interactions
with pests because of induced
chemical compounds
- Moderate drought:
decreases UV
sensitivity in plants
- More frequent drought
& rising temperatures
reduce productivity
Important implications for food security and quality
Environmental Effects Assessment Panel
Terrestrial ecosystems
Combined effects of predicted climate change & UV
radiation: plants and ecosystems
Climate-change-related reduced cloud cover (low latitudes)
Deforestation and other land-use changes
Increased UV radiation exposure
Reduces plant biomass
production
Promotes decay of
dead plant material
Effects on important ecosystem processes including
nutrient cycling and CO2 loss to the atmosphere
Environmental Effects Assessment Panel
Terrestrial ecosystems
Impacts of climate
change & land-use
change on organisms
and ecosystems
Impacts of climate
change & changes in
stratospheric ozone
on UV radiation
(includes increased
UV-B radiation in
some regions)
Implications for food security & food quality
Ecosystem responses to UV radiation & climate
Environmental Effects Assessment Panel
Aquatic ecosystems
KEY OUTPUTS
Assessment of the effects of future changes in
UV radiation, and interactions with other
environmental change on:
Aquatic organisms
and ecosystem
processes
Sensitivity of waterborne
human pathogens to UV
radiation
Environmental Effects Assessment Panel
Aquatic ecosystems
Ozone layer
Clouds,aerosols
Main factors
affecting the
quantity &
UV
quality of UV
attenuation radiation
received by
aquatic
organisms
Environmental Effects Assessment Panel
Aquatic ecosystems
•Water properties
•Ozone levels
•Clouds
•Elevation
Depth, m
Quantity & quality
of UV radiation
received by
aquatic organisms
depends on:
Dissolved organic
matter determines
UV penetration into
water
Penetration of UVIrradiance, % of surface B, UV-A radiation
& visible light
1
10
100
0
in an alpine lake
5
High UV irradiance
10
Low levels of
dissolved organic
matter – increased
penetration
15
20
Aquatic ecosystems
Changes in climate and UV are
expected to:
Dissolved organic
matter is a key
limiting factor for
UV penetration in
to water bodies
- Increase inputs of organic matter
in some areas of the oceans
- Increase the degradation of
dissolved organic matter
- The balance will vary between
different oceanic regions, but in
many areas, aquatic organisms
will be exposed to increased UV
radiation
Environmental Effects Assessment Panel
Aquatic ecosystems
Combined effects of predicted climate change &
UV radiation: global change processes
Environmental climate‐driven changes may exceed
protective strategies to adapt to UV radiation
Increasing temperature
increases breakdown of
dissolved organic material
Increasing CO2
Increases acidity (low pH)
Decreases skeletal formation
in calcified organisms
More exposure of aquatic
organisms to solar UV-B
Increased vulnerability to
solar UV‐B radiation
Environmental Effects Assessment Panel
Aquatic ecosystems
Impacts of changes
in temperature, CO2
and acidity on
aquatic organisms
and ecosystems
Impacts of climate
change & changes in
stratospheric ozone
on UV radiation
penetrating into
water bodies
Implications for food security
Ecosystem response to UV radiation & climate
Environmental Effects Assessment Panel
Carbon and other global
chemical cycles
KEY OUTPUTS
Assessment of the effects of future changes in UV
radiation and interactions with other
environmental change on:
The cycling of
carbon and other
elements
The potential for
“feedbacks” through
changes in global
element cycles
Environmental Effects Assessment Panel
Carbon and other global
chemical cycles
Ecosystem responses to UV radiation and climate
change will affect global chemical cycles,
resulting in feedbacks into environmental change
and its effects
Environmental Effects Assessment Panel
Carbon and other global
chemical cycles
Interactions between continuing changes in UV
radiation and the effects of other components of
environmental change are diverse and complex
Interactions are best defined in the oceans and involve:
- Decreased uptake of atmospheric CO2 by the oceans
- Increased production and release of nitrous oxide
from the oceans
Ecosystem response to UV radiation and climate
change will affect global chemical cycles, resulting
in feedbacks into environmental change and its
effects
Environmental Effects Assessment Panel
Carbon and other global
chemical cycles
Negative effects of
climate change &
UV radiation on
aquatic
organisms
Decreased CO2
uptake by the
oceans
Increased run-off of organic matter
from land into the oceans
UV-induced breakdown of this
organic matter
Increased CO2 emissions from the
oceans (also increased NOx )
Resulting increase in atmospheric CO2 may enhance
global warming beyond current predictions
Environmental Effects Assessment Panel
Carbon and other global
chemical cycles
Environmental Effects Assessment Panel
Tropospheric air quality
KEY OUTPUTS
Assessment of the interactive effects of ozone
depletion and other components of
environmental change on tropospheric ozone (at
low & mid-latitudes), and other tropospheric air
pollutants
Assessment of effects on human health and
ecosystems of breakdown products of ODS
substitutes (HCFCs and HFCs)
Environmental Effects Assessment Panel
Tropospheric air quality
•
UV initiates production of hydroxyl radicals (∙OH), which
are atmospheric ‘cleaning agents,’ destroying many air
pollutants, ODS, photochemical smog
•
With O3 recovery, less UV, as a result ∙OH is predicted to
decrease globally by ca 20% by 2100
Potential for increased photochemical smog, with
negative effects on human health and the
environment
Environmental Effects Assessment Panel
Tropospheric air quality
Surface (tropospheric) O3 in mid-latitudes is
predicted to increase because of climate change
and interactions with atmospheric chemistry
Drivers used in the models for this:
- doubling of CO2
- 50% increase in emissions of plant compounds
(isoprene)
- doubling of emissions of soil-derived NOx
(from human activity, and from the ocean)
Tropospheric air quality
CFC replacements break down into trifluoroacetic
acid (TFA) but this is currently judged to present a
negligible risk to human health or the environment
Environmental Effects Assessment Panel
Materials damage
KEY OUTPUTS
Assessment of effects of UV radiation and
climate change on construction materials
UV radiation
degradation of
plastics & wood
Damage due to high
temperatures, humidity, &
atmospheric pollutants
Assessment of availability of technologies as
protective measures/agents
Environmental Effects Assessment Panel
Materials damage
Effect of climatic variables on light-induced
degradation of materials
+, effectiveness
Environmental Effects Assessment Panel
Materials damage
UV radiation and climate change shorten useful
outdoor lifetimes of materials
• Development of technologies to
counteract these effects of UV
radiation and climate change
- allows service lifetimes of
materials to be maintained or
improved
• Use of plastic nanocomposites &
wood-plastic composites
• Increased use of nanomaterials
as stabilisers
Pine wood surface
after 2 years of
outdoor exposure
Environmental Effects Assessment Panel
Environmental Effects Assessment Panel
EEAP
8th ORM,
Geneve
Solar UV
radiation
Terrestrial and aquatic
ecosystems
Current & future climate
change interactions
with UV radiation add
to the uncertainty of
many aspects of
environmental impacts
Human health
Materials
Climate
change