influences of ozone layer depletion and climate change on uv-radiation: impacts on human health and...
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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
8th ORM, Geneve
Environmental Effects Assessment PanelEEAP
EEAP
Depletion of strato-spheric ozone (O3)
Stratospheric chemistry, climate
UV-B radiation
ODS applications, substitutes
O3 depleting substances
Human health
Ecosystem health and services
Materials
Air Quality
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
INTERACTIONSOzone depletion, climate change, UV radiation
UV changes in relation to impacts:Human health
Terrestrial ecosystemsAquatic ecosystems
Carbon and other global chemical cyclesAir qualityMaterials
KEY FOCUS AREAS (Full Assessment Report 2010)
Environmental Effects Assessment PanelEEAP
Ozone depletion, climate change, UV radiation
KEY OUTPUTS
*UV-B radiation, 280-315 nmEnvironmental Effects Assessment Panel
UV-B radiation causing sun-burn
Assessment of future predictions of the effects of O3, clouds & aerosols for:
UV-B radiation involved in human
vitamin D production
Ecosystems, construction materials
Current UV-B radiation compared with 1980
Ozone depletion, climate change, UV radiation
At mid-latitudes: increases in UV-B radiation by ca 5%
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 high latitudes (areas of large O3 depletion): large
increases in UV-B radiation
Sufficient to cause sunburn
Environmental Effects Assessment Panel
Projected future changes in UV: ozone and clouds
Ozone depletion, climate change, UV radiation
At high latitudes: cloud cover increases (by ca 5%)
Reduction of UV radiation(UV already low)
Less easy to achieve exposure times needed to
produce sufficient vitamin D
At low latitudes (near the equator): cloud cover decreases by ca 3%
Increase in UV radiation(UV already high)
Greater risk of sun-burn: additional increase in
sunburning-UV of 3 to 6%
Environmental Effects Assessment Panel
1980 2020 2040 2065Total chlorine (ppbv) 2 11.5 20 40O3 (DU) 310 250 220 100Maximum UV Index 10 12.5 15 30
The Montreal Protocol has PREVENTEDlarge increases in sun-burning UV
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
Environmental Effects Assessment Panel
Skin and eye diseases (especially
cancers)
Assessment of the effects of UV radiation, and interactions with other environmental change,
on human health, including:
Immune responses
Vitamin D production
KEY OUTPUTS
Exposure to sunburning UV-B radiation is a major environmental risk for skin cancers
M. N
orv
al
Cutaneous malignant melanoma
Squamous cell carcinoma
Basal cell carcinoma
Environmental Effects Assessment Panel
The Montreal Protocol has PREVENTED
large increases in skin cancers that would have
resulted from uncontrolled ozone
depletion
ALTHOUGH incidence currently is high
Human health
Environmental Effects Assessment Panel
Malignant melanoma of the eyeMost common eye cancer in adults and may be a link between its incidence and UV-B radiation
UV-induced allergyOccurs in ca 5-20% of the population often after first spring/summer exposure to UV radiation
UV-induced immune-suppressionComplex effect but increased UV exposure may have significant effects on infectious diseases and auto-immune diseases
Human health
Need to balance the risks of over-exposure to UV radiation with the potential beneficial effects
Importance of vitamin D
Environmental Effects Assessment Panel
Vitamin D is produced in the skin following UV-B irradiation
Supports bone health
May decrease risk of:
- 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
Human health
Environmental Effects Assessment Panel
Balance between sun-burning UV-B radiation and that needed for vitamin-D, and the effects of future environment
change remain unclear
Human health
Solar UV-B at mid-high latitudes are
below that required for adequate Vitamin
D synthesis from Autumn-Spring
• 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
Combined effects of climate change & solar UV radiation
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
Human health
Terrestrial ecosystems
Environmental Effects Assessment Panel
Food security & food quality
Assessment of the effects of future changes in UV radiation, and interactions with other
environmental change on:
Ecosystem responses to UV radiation & climate
Assessment of effects of ozone depletion since 1980 on current plant productivity
KEY OUTPUTS
- UV
•Green pigment used for energy capture & growth
•Loss of green pigment
•Reduced growth
+ UV
Growth reductions are due to direct damage plus diversion of plant resources towards protection and repair
Terrestrial ecosystems
Plant growth has been reduced by ca 6% in response to increased UV radiation in areas of significant ozone
depletion
Plant growth has been reduced by ca 6% in response to increased UV radiation in areas of significant ozone
depletion
Terrestrial ecosystems
- long-term effects of reduced plant growth may be important for potential carbon capture/retention
- Interactions with other components of climate change
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
Important implications for food security and qualityEnvironmental Effects Assessment Panel
-Moderate drought: decreases UV sensitivity in plants
- More frequent drought & rising temperatures reduce productivity
Terrestrial ecosystems
Climate-change-related reduced cloud cover (low latitudes)Deforestation and other land-use changes
Increased UV radiation exposure
Environmental Effects Assessment Panel
Promotes decay of dead plant material
Reduces plant biomass production
Effects on important ecosystem processes including nutrient cycling and CO2 loss to the atmosphere
Terrestrial ecosystems
Combined effects of predicted climate change & UV radiation: plants and ecosystems
Implications for food security & food qualityEcosystem responses to UV radiation & climate
Environmental Effects Assessment Panel
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)
Terrestrial ecosystems
Aquatic ecosystems
Environmental Effects Assessment Panel
Aquatic organisms and ecosystem
processes
Assessment of the effects of future changes in UV radiation, and interactions with other
environmental change on:
Sensitivity of waterborne human pathogens to UV
radiation
KEY OUTPUTS
Aquatic ecosystems
Ozone layer
Clouds,aerosols
UV attenuation
Environmental Effects Assessment Panel
Main factors affecting the quantity & quality of UV radiation received by aquatic organisms
Quantity & quality of UV radiation received by aquatic organisms depends on:
•Water properties•Ozone levels•Clouds•Elevation
Aquatic ecosystems
Dissolved organic matter determines UV penetration into water
High UV irradiance
Low levels of dissolved organic matter – increased penetration
Penetration of UV-B, UV-A radiation
& visible light in an alpine lake0
5
10
15
20
1 10 100
Dep
th, m
Irradiance, % of surface
UV-B, 305 nm
UV-A, 380 nm
Visible lig
ht
Aquatic ecosystems
Environmental Effects Assessment Panel
Dissolved organic matter is a key
limiting factor for UV penetration in to water bodies
Changes in climate and UV are expected to:
- 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
Aquatic ecosystems
Environmental climate‐driven changes may exceed protective strategies to adapt to UV radiation
Combined effects of predicted climate change & UV radiation: global change processes
Environmental Effects Assessment Panel
Increasing temperature
increases breakdown of dissolved organic material
More exposure of aquatic organisms to solar UV-B
Increasing CO2
Increases acidity (low pH)
Decreases skeletal formation in calcified organisms
Increased vulnerability to solar UV‐B radiation
Aquatic ecosystems
Environmental Effects Assessment Panel
Implications for food securityEcosystem response to UV radiation & climate
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
Carbon and other global chemical cycles
Environmental Effects Assessment Panel
The cycling of carbon and other
elements
Assessment of the effects of future changes in UV radiation and interactions with other
environmental change on:
The potential for “feedbacks” through
changes in global element cycles
KEY OUTPUTS
Environmental Effects Assessment Panel
Ecosystem responses to UV radiation and climate change will affect global chemical cycles,
resulting in feedbacks into environmental change and its effects
Carbon and other global chemical cycles
Environmental Effects Assessment Panel
Ecosystem response to UV radiation and climate change will affect global chemical cycles, resulting
in feedbacks into environmental change and its effects
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
Carbon and other global chemical cycles
Environmental Effects Assessment Panel
Negative effects of climate change & UV radiation on
aquatic organisms
Decreased CO2 uptake by the
oceans
Resulting increase in atmospheric CO2 may enhance global warming beyond current predictions
Increased run-off of organic matter from land into the
oceans
UV-induced breakdown of this organic matter
Carbon and other global chemical cycles
Environmental Effects Assessment Panel
Carbon and other global chemical cycles
Tropospheric air quality
Environmental Effects Assessment Panel
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)
KEY OUTPUTS
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
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)
Surface (tropospheric) O3 in mid-latitudes is predicted to increase because of climate change
and interactions with atmospheric chemistry
Tropospheric air quality
Environmental Effects Assessment Panel
CFC replacements break down into trifluoroacetic acid (TFA) but this is currently judged to present a negligible risk to human health or the environment
Materials damage
Environmental Effects Assessment Panel
UV radiation degradation of
plastics & wood
Assessment of effects of UV radiation and climate change on construction materials
Damage due to high temperatures, humidity, &
atmospheric pollutants
Assessment of availability of technologies as protective measures/agents
KEY OUTPUTS
Environmental Effects Assessment Panel
Effect of climatic variables on light-induced degradation of materials
+, effectiveness
Materials damage
•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
UV radiation and climate change shorten useful outdoor lifetimes of materials
Environmental Effects Assessment Panel
Pine wood surface after 2 years of
outdoor exposure
Materials damage
8th ORM, Geneve
Environmental Effects Assessment PanelEEAP
Solar UV radiation
Terrestrial and aquatic ecosystems
Human health
Materials
Climatechange
Current & future climate change interactions
with UV radiation add to the uncertainty of
many aspects of environmental impacts
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