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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,

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Presentation on theme: "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,"— Presentation transcript:

1 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 Panel EEAP

2 Depletion of strato- spheric ozone (O 3 ) Stratospheric chemistry, climate UV-B radiation ODS applications, substitutes O 3 depleting substances Human health Ecosystem health and services Materials Air Quality

3 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

4 INTERACTIONS Ozone depletion, climate change, UV radiation UV changes in relation to impacts: Human health Terrestrial ecosystems Aquatic ecosystems Carbon and other global chemical cycles Air quality Materials KEY FOCUS AREAS (Full Assessment Report 2010) Environmental Effects Assessment Panel EEAP

5 Ozone depletion, climate change, UV radiation KEY OUTPUTS *UV-B radiation, nm Environmental Effects Assessment Panel UV-B radiation causing sun-burn Assessment of future predictions of the effects of O 3, clouds & aerosols for: UV-B radiation involved in human vitamin D production Ecosystems, construction materials

6 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 O 3 depletion): large increases in UV-B radiation Sufficient to cause sunburn Environmental Effects Assessment Panel

7 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

8 Total chlorine (ppbv) O 3 (DU) Maximum UV Index The Montreal Protocol has PREVENTED large 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

9 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

10 Exposure to sunburning UV-B radiation is a major environmental risk for skin cancers M. Norval Cutaneous malignant melanoma Squamous cell carcinoma Basal cell carcinoma Non -melanoma 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

11 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 UV-induced immune-suppression Complex effect but increased UV exposure may have significant effects on infectious diseases and auto-immune diseases Human health

12 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

13 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

14 Higher temperatures may lead to more skin cancers For the same UV exposure, for every 10 o C 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

15 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

16 - 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

17 Terrestrial ecosystems - long-term effects of reduced plant growth may be important for potential carbon capture/retention - Interactions with other components of climate change

18 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 quality Environmental Effects Assessment Panel - Moderate drought: decreases UV sensitivity in plants - More frequent drought & rising temperatures reduce productivity Terrestrial ecosystems

19 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 CO 2 loss to the atmosphere Terrestrial ecosystems Combined effects of predicted climate change & UV radiation: plants and ecosystems

20 Implications for food security & food quality Ecosystem 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

21 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

22 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

23 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 lake Depth, m Irradiance, % of surface UV-B, 305 nm UV-A, 380 nm Visible light

24 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

25 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 CO 2 Increases acidity (low pH) Decreases skeletal formation in calcified organisms Increased vulnerability to solar UV B radiation

26 Aquatic ecosystems Environmental Effects Assessment Panel Implications for food security Ecosystem response to UV radiation & climate Impacts of changes in temperature, CO 2 and acidity on aquatic organisms and ecosystems Impacts of climate change & changes in stratospheric ozone on UV radiation penetrating into water bodies

27 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

28 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

29 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 CO 2 by the oceans - Increased production and release of nitrous oxide from the oceans Carbon and other global chemical cycles

30 Environmental Effects Assessment Panel Negative effects of climate change & UV radiation on aquatic organisms Decreased CO 2 uptake by the oceans Resulting increase in atmospheric CO 2 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 Increased CO 2 emissions from the oceans (also increased NOx ) Carbon and other global chemical cycles

31 Environmental Effects Assessment Panel Carbon and other global chemical cycles

32 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

33 Tropospheric air quality UV initiates production of hydroxyl radicals ( OH), which are atmospheric cleaning agents, destroying many air pollutants, ODS, photochemical smog With O 3 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

34 Tropospheric air quality Drivers used in the models for this: - doubling of CO % increase in emissions of plant compounds (isoprene) - doubling of emissions of soil-derived NOx (from human activity, and from the ocean) Surface (tropospheric) O 3 in mid-latitudes is predicted to increase because of climate change and interactions with atmospheric chemistry

35 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

36 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

37 Environmental Effects Assessment Panel Effect of climatic variables on light-induced degradation of materials +, effectiveness Materials damage

38 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

39 8th ORM, Geneve Environmental Effects Assessment Panel EEAP Solar UV radiation Terrestrial and aquatic ecosystems Human health Materials Climate change Current & future climate change interactions with UV radiation add to the uncertainty of many aspects of environmental impacts


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