Presentation on theme: "Environmental Effects Assessment Panel"— Presentation transcript:
1 Environmental Effects Assessment Panel 22nd MOPBangkokEnvironmental Effects Assessment PanelEEAPEnvironmental effects of ozone depletion and its interactions with climate change Janet F. Bornman, co-chair Nigel Paul, Xiaoyan Tang, co-chairs
2 SAP EEAP TEAP Stratospheric chemistry, climate Depletion of strato-spheric ozone (O3)UV-B radiationO3 depleting substancesAir QualityEcosystem health and servicesMaterialsHuman healthODS applications, cost-effective options
3 Environmental Effects Assessment Panel EEAP 22nd MOPBangkokEnvironmental Effects Assessment Panel EEAPKEY FOCUS AREAS FROMTHE FULL ASSESSMENT REPORT 2010Interactions with climate changeOzone depletion, climate change, UV radiation Human health Terrestrial ecosystems Aquatic ecosystems Biogeochemical cycles Air quality Materials
4 Ozone depletion, climate change, UV radiation KEY FINDINGSStrong interactions between O3 depletion& climate changeFuture predictions for sun-burning UV-B radiation - effects of O3, clouds & aerosolsConsequences for human Vitamin DproductionWorld avoided – implications for effects(UV-B radiation, nm)Environmental Effects Assessment Panel
5 sufficient to induce sunburn Ozone depletion, climate change, UV radiationCurrentlyUV-B radiation: Large variability due to clouds & aerosolsMid-latitudes: increased UV-B irradiances: ca 5% relative to 1980Large increases in UV-B radiation in areas of large O3 depletionsufficient to induce sunburnS Hemisphere: cloudier overall than corresponding NH(global satellite data)
6 Ozone depletion, climate change, UV radiation Projected changes in ozone and cloudsCloud cover increases at high latitudes (by ca 5%)Reduction of UV radiation(UV already low)More difficult to achieve optimal exposure times for sufficient vitamin D productionCloud cover decreases at low latitudes by ca 3% (near the equator)Increase in UV radiation(UV already high)Additional increase in sunburning-UV of 3 to 6%
7 The Montreal Protocol has PREVENTED large increases in sun-burning UV radiation (UV index)1980202020402065Total chlorine (ppbv)211.52040O3 (DU)310250220100UV Indexmax1012.51530UV Index: an estimation of the UV levels important for the effects on the human skincalculated using observed & currently predicted chlorine concentrationsUV index for clear skies predicted by a climate-chemistry model versus year for two future scenarios: (black curve) the “world avoided” by implementing the Montreal Protocol, and (red curve) a “reference future” calculated using the observed and currently predicted chlorine concentrations. The UV index is calculated using the July 30o – 50o N zonal-mean ozone, and for local noon on 2 July. The horizontal grey line shows the 1975–1985 average from the fixed chlorine simulation
8 Human health Impacts of UV-B radiation on: KEY FINDINGSImpacts of UV-B radiation on:Increasing cataract & skin cancer incidenceDecreased immunityInteractions with climate changeVitamin D productionEnvironmental Effects Assessment Panel
9 Environmental Effects Assessment Panel Human healthNeed for balancing potential beneficial effects of UV with over-exposure: Importance of vitamin DProduced in the skin following UV-B irradiationSupports bone healthMay decrease risk of:- several internal cancers- autoimmune & infectious diseases- cardiovascular diseasesEffectiveness of oral vitamin D supplementation?High vitamin D status beneficial?Internal cancers.Suggested mechanismSolar UV radiation prevents cancer through vitamin D productionEnvironmental Effects Assessment Panel
10 Human health Exposure to sunburning UV-B radiation Major environmental risk for skin cancersCutaneous malignant melanomaSquamous cell carcinomaSUPER-IMPOSE A TEXT BOX WITH INFO BELOW:annual incidence of cutaneous malignant melanoma (CMM) varies geographically from between 5 and 24 per 100,000 in Europe and the USA34-36 to over 70 per 100,000 in higher ambient UV radiation regions of Australia and New Zealand Even in locations with lower incidence, there are specific high-risk groups such as non-Hispanic white men older than 65 years in the USA, where the incidence is greater than 125 cases per 100, In Australia, melanoma is currently the third most commonly reported cancer in men and women overall, and the commonest in women aged years.40 CMM is uncommon in individuals under the age of 20, although an increase of 2.9% per year between 1973 and 2003 in the USA has been reported in a recent review.41Many studies in various countries indicate that the incidence of CMM has increased by 1-3% per year over the past half century In a few instances it has stabilised over recent years,37, 47 particularly in people younger than 40 years. For example, in Sweden, the previously rapid increase in the incidence of CMM in teenagers from 1973 levelled off between 1983 and 1992, and since then has decreased.48 This situation has been attributed to intensive public health campaigns over the past 30 years or so advocating avoidance of sunburn and seeking medical care promptly if pigmented skin lesions arise.49-53_______________non-melanoma skin cancers (NMSCs): basal cell carcinoma (BCC) and squamous cell carcinoma (SCC) For example, the incidence of BCC increased by 3% per year from in the UK,75 and the incidence of SCC increased four-fold from in Sweden.54 The incidence of NMSC in Australia in 2002 was five times greater than the incidence of all other cancers combined.76Non-melanomaBasal cell carcinomaM. NorvalEnvironmental Effects Assessment Panel
11 Human health Most common eye cancer in adults May be a link between UV-B radiation & incidenceMalignant melanoma of the eyeA. CullenOccurs in ca 5-20% of the populationOften after first spring/summer exposureUV-induced allergyS. IbbotsonLegend: Figure 1. Intraocular malignant melanoma: (a) an amelanotic iris melanoma with nutrient blood vessels, causing a rolling out (ectropion) of the pigment layer and distortion of the pupil, and (b) a dome-shaped choroidal melanoma with mottled appearance (photographs supplied by Dr A, Cullen, University of Waterloo, Canada).Ocular melanomaLimited evidence indicates that there may be a link between solar UV-B radiation and the development of ocular melanoma. Such tumours include both external, involving the eyelid and conjunctiva, and intraocular tumours, involving the iris, ciliary body and choroid (collectively known as the uvea). The latter comprise the majority of ocular melanomas and are the most common primary eye cancer in adults with a reported annual incidence per million of 6 in fair-skinned and 0.3 in dark-skinned individuals______________UV-induced sun allergyPolymorphic light eruption (PLE) is the most common of the disorders that are provoked by sunlight, occurring in about 5-20% of the population. It is most frequent in the spring or early summer, or during a sunny holiday, following the first exposure to an intense dose of sunlight, and is characterised by red, itchy skin eruptions (Figure 4).Figure 4. Subject with polymorphic light eruption showing pruritic skin eruptions on sun-exposed body sites (photograph supplied by Dr S. Ibbotson, University of Dundee, Scotland).
12 World avoided: Human health protected By 2065: Peak values of sun-burning UV radiation could have tripled at mid-northern latitudesWith the MP, clear-sky UV radiation_only slightly greater than that prior to the start of O3 depletionFuture sun-burning UV radiation with and without the Montreal Protocol.Sun-burning UV radiation with and without the Montreal ProtocolP. Newman, R. McKenzie
13 Human health Combinations of climate change & solar UV radiation Higher temperatures likely lead to more skin cancersFor the same UV irradiance: for every 10C increase, estimated 3-6% increase in skin cancersSeveral indications of further interactionsIncrease in certain infectious diseases (malaria, Lyme)Increase in allergic diseasesSuppression of the immune response to diseaseIncreased photosensitivity of the skin (temp., dust -deserts)Higher temperatures likely lead to more skin cancers for the same exposureto UV radiationLyme disease (a bacterial infection spread by ticks) and leishmaniasis (a protozoal infection spread by sand-fly bites)Climate factors suggested to affect infectious and other human diseases include increased water temperature leading to increased survival of waterborne agents, increased rainfall leading to increased breeding sites for insect vectors, increased humidity leading to enhanced microbial survival in the environment, decreased seasonal exposure to solar UV-B radiation leading to lower vitamin D levels with diminished protective effects, increased atmospheric pollutants leading to less efficient mucociliary action, and changing rainfall patterns and ocean temperatures that result from long term natural variabilities such as the El Nino Southern Oscillation events.Skin sensitivity increase:UV, andRecent changes in the climate of Pusan include increased air temperature all year round, expanding desertification with Asian dust and a year-by-year increase in sunshine duration.
14 Terrestrial ecosystems KEY FINDINGSDecreased plant productivity in areas of large ozone depletionClimate change & land-use change:Regional increased UV-B radiationUV radiation and climate change:- Implications for food security & quality- Evolving ecosystem modifications & acclimation to UV radiation & climateEnvironmental Effects Assessment Panel
15 Terrestrial ecosystems Plant productivity & adaptation/repairPlant growth is reduced in response to increased UVca 6% reduction in plant growth since 1980 in areas of significant ozone depletionCaused by:- direct damage- increased diversion of plant resources towards protection and repair processesConsequences:- long-term effects of reduced plant growth may be important for potential carbon capture/retention
16 UV-B radiation causes damage in Antarctic plants Loss of green pigmentReduced growthGreen pigment used for energy capture & growthPigment loss+ UV- UVHigh pigment levelsUV-B causes -yellow plantsLoss of chlorophyllIncrease in antioxidant pigmentsNo change in UV-B screening pigmentsShorter stemsFirst evidence of negative effect of UV on an Antarctic plantLeaf density 7% higher under UV26% of leaves mutant form compared with 12% without UVConfocal pics show healthy chlorophyll as red, can see in the UV treatment cells with no chlorophyll and that means no photosynthesis.Microscopic viewsTurnbull et al. 2005
17 Many plants produce screening pigments that protect against UV damage (induced antioxidants) MossesLettuce+ UV+ UV- UVOther examples of the protective molecules produced by plants, in response to UV radiation include the red pigments seen in lettuces (c; top), whilst those shielded from UV are mostly green. Similarly, Antarctic mosses shielded by small stones are green (d: centre) whilst the plants around them produce protective red pigments. Nigel’s lettuce picture+ UVS. RobinsonN. Paul
18 Terrestrial ecosystems Combinations of predicted climate change & UV radiationEffects on plant and ecosystem responseExample 1Spread of plant pests with increasing temperature, rainfall+ >>> UV-B radiation: large effects on plant interactions with pestsInduces increases in certain compoundsusually decreases plant consumption by e.g. insectsImportant implications for food security and quality
19 Terrestrial ecosystems Combinations of predicted climate change & UV radiationEffects on plant and ecosystem responseExample 2Moderate drought: decreases UV sensitivity in plantsBut further decreases in rain + increasing temperatures:Reduced plant growth and survivalEnvironmental Effects Assessment Panel
20 Terrestrial ecosystems UV radiation and global environmental changeExample 3Predicted reduced cloud cover (low latitudes)DeforestationLand-use changesIncreased UV radiationexposurePromotes decay of dead plant materialimportant ecosystem process fornutrient cyclingalso CO2 loss to the atmosphere
21 Aquatic ecosystemsKEY FINDINGSIncreased exposure to UV radiation with climate changePotentially greater vulnerability to UV radiationChanges in UV transparency of watersIncreased in some regionsDecreased in othersConsequences for sensitivity of waterborne human pathogens to UV radiationDetrimental effects of solar UV‐B radiation have been demonstrated for many aquatic organisms. In contrast, relatively little information is available regarding consequences on biodiversity and species composition as well as the interactions between trophic levels within natural ecosystems.Climate change will alter the exposure of aquatic organisms to solar UV radiation by influencing their depth distribution as well as the transparency of the water. Increased temperature due to climate change tends to decrease the depth of the upper mixed layer, thus exposing cells to higher irradiances. Dissolved organic matter (DOM) is the major factor influencing UV transparency in most inland waters and coastal areas. In some regions, DOM concentrations have nearly doubled in the past 20 years. Since some waterborne human pathogens are sensitive to solar UV radiation, changes in DOM may alter their exposure and inactivation.Environmental Effects Assessment Panel
22 Environmental Effects Assessment Panel Main factors affecting the quantity & quality of UV radiation received by aquatic organismsOzone layerUV attenuationClouds,aerosolsMain factors affecting the quantity and quality of UV radiation received by aquatic organisms
23 Penetration of UV-B, UV-A radiation and visible light in an alpine lakeHigh UV irradianceLow levels of dissolved organic matter >>> penetrationIrradiance as % of surface110100UV-B, 305 nm5UV-A, 380 nmDepth, m10Visible light1520Environmental Effects Assessment Panel
24 Aquatic ecosystems Climate change and solar UV radiation Environmental climate‐driven changes may exceed protective strategies to adapt to UV radiationIncreasing temperatureincreases breakdown of dissolved organic materialMore UV exposure to aquatic organismsIncreasing CO2Increases acidity (low pH)Decreases skeletal formation in calcified organismsmore vulnerable to solar UV‐B radiationIncreases acidityDecreases skeletal formation in calcified organisms (e.g., phytoplankton, corals)
25 Biogeochemical cycles KEY FINDINGSUV radiation & climate change interactions accelerate global carbon cyclingEffect of decreased uptake of atmospheric CO2 by oceans on living organismsCauses & consequences of increased production and release of nitrous oxideEnvironmental Effects Assessment Panel
26 in terrestrial and aquatic ecosystems Central to UV and climate changeSolar UVradiationCarbon cyclingin terrestrial and aquatic ecosystemsClimatechangeBiogeochemistryof trace gasesand aerosolsFeedbacksQuantification of the scale remains difficult, but the interactions and feedbacks have been established
27 Biogeochemical cycles Predicted increase in atmospheric CO2 may enhance global warming beyond current predictionsProjected warmer and drier conditions increasesUV-induced breakdown of dead plant materialNegative effects of climate change & UV radiation on aquatic organisms decrease uptake of atmospheric CO2 by the oceansClimate-related increases in run-off of organic material from land to oceans and UV-induced breakdown of this material increase emission of CO2 from the oceans
28 Biogeochemical cycles Increasing production of nitrous oxide, (N2O) Climate-related increase in run-off also increases nitrogen input in to the oceans; further N inputs from atmosphereIncreasing production of nitrous oxide, (N2O)Increases O3-depletion Increases the GH effectIncreases UV radiationN2O: Mainly from natural sources & human activities (e.g., agric.)_____________________________Oxygen depletion in the ocean, coupled with increased inputs of reactive nitrogen from rivers and the atmosphere, will lead to changes in nitrogen cycling that will result in increased production and release of nitrous oxide that will further increase global warming as well as stratospheric ozone depletion (Figure 7) As CFC emissions drop in response to compliance to the Montreal Protocol, the importance of nitrous oxide as an ozone depleting substance (ODS) will escalate throughout the 21st century.___________________________From Richard ZClimate-change related changes in circulation are leading to decreases in oxygen concentrations that enhance nitrous oxide production in the ocean. The increases in N2O production are projected to be particularly pronounced in near coastal areas as shown in Figure 7. The UV connection relates to the fact that N2O is playing an important role in stratospheric ozone depletion (which enhances UV-B radiation reaching the Earth's surface), This role is on the upswing as N2O fluxes increase and CFC levels decrease. N2O also is an important greenhouse gas and increases in stratification linked to climate change lead to reduced productivity and increased UV penetration into the upper ocean. This in turn positively feeds back to oceanic N2O production by reinforcing decreases in oceanic oxygen concentrations._______________
29 Tropospheric air quality KEY FINDINGSProjected increase in tropospheric ozone(low & mid-latitudes)Implications of changes in climate, pollutants & stratospheric O3 on human health & the environmentLikely insignificant effect of breakdown products of ODS substitutes-hydrochlorofluorocarbons (HCFCs)-hydrofluorocarbons (HFCs)Future changes in emissions of pollutants together with changes in climate and stratospheric ozone will modify the chemistry of the lower atmosphere and thus directly affect human health and the environment. Ultraviolet radiation is one of the controlling factors for the formation of photochemical smog which includes tropospheric ozone and aerosols; it also initiates the production of hydroxyl radicals, which control the amount of many climate- and ozone-relevant gases in the atmosphere. Uncertainties still exist in quantifying the chemical processes and wind-driven transport of pollutants. The net effects of future changes in UV radiation, meteorological conditions, and anthropogenic emissions may be large but will depend on local conditions, posing challenges for prediction and management of air quality.Aerosols composed of organic substances have a major role for climate and air quality, and contribute a large uncertainty to the energy budget of the atmosphere. Aerosols are mostly formed via the UV-initiated oxidation of volatile organic compounds from anthropogenic and biogenic sources, although the details of the chemistry are still poorly known and current models under-predict their abundance. A better understanding of their formation, chemical composition, and optical properties is required to assess their significance for air quality and to better quantify their direct and indirect radiative forcing of climate.Environmental Effects Assessment Panel
30 ∙OH is predicted to decrease globally by ca 20% by 2100 Tropospheric air qualityFuture changes in UV radiation & climate will modifyair qualityUV initiates production of hydroxyl radicals (∙OH)A controlling factor of photochemical smogWith O3 recovery, less UV∙OH is an atmospheric ‘cleaning agent,’ destroys many air pollutants, ODS, GHGs∙OH is predicted to decrease globally by ca 20% by 2100Certain regions of low and middle latitudesTropospheric ozone - projected to increase over the next years because of interactions of emissions (nitrogen oxides), chemical processes, and climate change drivers (temperature, humidity)Of concern for future protection of human health and the environmentConsequencesPotential for increased photochemical smogNegative effects on human health, environment
31 Tropospheric air quality Predicted changes in surface ozone between 2000 & 2050 because of climate change and interactions with atmospheric chemistryTropospheric air qualityFurther increase in tropospheric O3 in mid-latitudes(ca 4 ppbv)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)Alternate graphic for Figure 4Predicted changes in surface ozone between 2000 and A, shows changes predicted for additional emissions of precursors. B, shows the change in ozone predicted to result from changes in climate. C, shows the result for the Combined impact of increased emissions of precursors of O3 and increases resulting from climate change.
32 Breakdown of CFC replacements into trifluoroacetic acid (TFA) Salt lakes with no outflow, loss by evaporation only – negligible effects from TFASmall fraction of TFA from natural sources – negligible effectBreakdown in soil and waterTFAHFCs, HFOs, and HCFCsCF3- CXyHOCF3-C-OHCF2Cl-C-OHBreakdown of CFC replacements into trifluoroacetic acid (TFA)chloro-difluoroaceticQ&A CH6 Fig 2The main breakdown product, trifluoroacetic acid (TFA) and other related short-chain fluorinated acids are presently judged to present a negligible risk to human health or the environment.The hydrofluorocarbons (HFCs) and hydrochlorofluorocarbons (HCFCs) are replacements for the chlorofluorocarbons (CFCs) as they have a smaller effect on the ozone layer. The HFCs and HCFCs are largely degraded before reaching the stratosphere.HFCs and HCFCs break down relatively rapidly into several products including persistent substances such as trifluoroacetic acid (TFA) and chlorodifluoroacetic acid. The compounds are washed from the atmosphere by precipitation and reach surface waters, along with other chemicals washed from the soil. Microbiological degradation slowly removes these substances from the water. In locations where there is little or no outflow and high evaporation (seasonal wetlands and salt lakes), these products are expected to increase in concentration over time.The effects of increased concentrations of these naturally occurring mineral salts (from natural sources such as undersea vents and volcanic activity) and other materials would be greater and more biologically significant than those of breakdown products of the HFCs and HCFCs. TFA is very resistant to breakdown, and amounts deposited in flowing surface water will ultimately accumulate in the oceans. Based on estimates of current and future use of HFCs and HCFCs, additional inputs to the ocean will add only fractionally (less than 0.1%) to amounts already present.___________________________Decomposition of substitutes for ozone-depleting substances (ODS)hydrochlorofluorocarbons (HCFCs) and hydrofluorocarbons (HFCs)can break down into trifluoroacetic acid (TFA) and monofluoroacetic acid MFAaccumulates in oceans, salt lakes, and desert basins (playas)However, increased loadings of TFA and MFA judged to have an insignificant effect on humans and other organisms__________________From previous report:Trifluoroacetic acid -- breakdown product of HCFC, HFCNo new evidence to suggest that TFA will have adverse effects on humans or the environmentWorst-case estimate of release of TFA from complete conversion of HFCs and HCFCs global increase of 22,000 kt of TFA by planned phase-out of the HFCs and HCFCsincrease in TFA in the oceans by ca ng/lTFA: currently judged to present a negligible risk to human health or the environment
33 Materials damage Implications of climate change for KEY FINDINGSImplications of climate change forconstruction materialsUV radiation degrades plastics & woodIncreased damage with high temperatures, humidity, & atmospheric pollutantsCurrent availability of photostabilisers as protective measures/agentsEnvironmental Effects Assessment Panel
34 Effect of climatic variables on light-induced degradation of materials +, effectivenessIncrease in Solar UVIncrease in Temp.Increase in HumidityIncrease in PollutantsS, NOx, O3Polymer++++++++Wood++
35 Environmental Effects Assessment Panel Materials damageUV radiation and climate change shorten useful outdoor lifetimes of materialsImproved stabilisation technologiesAllow service lifetimes of materials to be maintained or improvedSome control of deleterious environmental effectsStabilisersRelatively high solar UV radiation stabilityPlastic nanocomposites and wood-plastic compositesNanofillers in compositesImproved stabilisation technologiesallow service lifetimes of materials to be maintained or improved, despite increased solar UV-B levelscan control the deleterious effects of environments with enhanced UV radiation and temperature to some extent and only for some types of the common plasticsrelatively high solar UV stabilityPlastic nanocomposites and wood-plastic compositesuse of nanofillers in composites is effectiveEnvironmental Effects Assessment Panel
36 UV radiation discoloration effects on polymer pigments UV-caused chalking of vinyl siding & rundown with rainUV-caused chalking from titanium dioxide in rigid PVCDegraded surfaces release titanium dioxide bound in the PVC matrixTitanium dioxide (TiO2)-photostabiliser for plasticsTitanium dioxide (TiO2) Photostabiliser for plasticsshows chalking due to UV degradation of vinyl (or PVC) siding and rundown with rain waterChalking in rigid PVC siding is due to UV in sunlight. This is because the degradation of surfaces releases the titanium dioxide bound in the PVC matrix. When the hand is run over the siding, the titanium dioxide ribs off like chalkDiscoloration due to UV is common. This shows that the organic pigment in the polymer or paint underwent degradation and changed color (not the plastic itself)______________________Control of photodegradation of plastics & wood:Using surface modification with appropriate coating chemistryClear polyurethane coatings reduce UV-B-induced yellowing/ discoloration of woodPhotostabilisers for plastics:Hybrid organic-inorganic polymers (ceramers)
37 Adapted from Fabiyi et al. 2008 & Taylor et al., 2009 Materials damageUse of composites to lessen UV degradation of materialsAdapted from Fabiyi et al & Taylor et al., 2009Products made with wood-plastic compositesPine wood surface after 2 years of outdoor exposureFigure 1: Left: Magnified image (electron micrograph) of HDPE/Pine wood composite with an inset at the same magnification, showing the surface after 2 years of outdoor exposure in Idaho (USA). Adapted from Fabiyi et al., Right: Processed wood plastic composite product. Reproduced with permission from Taylor et al., 2009.
38 Terrestrial and aquatic ecosystems LINKAGES: Environmental effects of O3 depletion & its interactions with climate changeTerrestrial and aquatic ecosystemsCurrent & future climate change interactions with UV radiation add to the uncertainty of many aspects of environmental impactsSolar UVradiationClimatechangeProcesses are defined, but the magnitude of the effects remains a challengePrevious central box:Changes in the concentration ofaerosols and atmospheric gases:Stratospheric ozone andozone-depleting gasesCO2 and other greenhouse gasesAerosols and gases that affecttropospheric air qualityHuman healthMaterials
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