influences of ozone layer depletion and climate change on uv-radiation: impacts on human health and...

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)


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


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


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%


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


Human health


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


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


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


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


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)


Human health

Terrestrial ecosystems


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


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


- 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


Climate-change-related reduced cloud cover (low latitudes)Deforestation and other land-use changes

Increased UV radiation exposure


Promotes decay of dead plant material

Reduces plant biomass production

Effects on important ecosystem processes including nutrient cycling and CO2 loss to the atmosphere


Combined effects of predicted climate change & UV radiation: plants and ecosystems

Implications for food security & food qualityEcosystem responses to UV radiation & climate


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)


Aquatic ecosystems


Aquatic organisms and ecosystem

processes

Assessment of the effects of future changes in UV radiation, and interactions with other


Sensitivity of waterborne human pathogens to UV

radiation

KEY OUTPUTS

Aquatic ecosystems

Ozone layer

Clouds,aerosols

UV attenuation


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


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


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


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


The cycling of carbon and other

elements

Assessment of the effects of future changes in UV radiation and interactions with other


The potential for “feedbacks” through

changes in global element cycles

KEY OUTPUTS


Ecosystem responses to UV radiation and climate change will affect global chemical cycles,

resulting in feedbacks into environmental change and its effects



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



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


Tropospheric air quality


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


• 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



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



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


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


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


Pine wood surface after 2 years of

outdoor exposure

Materials damage

8th ORM, Geneve


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

influences of ozone layer depletion and climate change on uv-radiation: impacts on human health and...

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