Air Pollution

Air PollutionAir Pollution

THE AIR AROUND USTHE AIR AROUND US

Air pollution-physical or chemical changes brought Air pollution-physical or chemical changes brought about by natural processes or human activities that about by natural processes or human activities that result in the decrease of air quality result in the decrease of air quality

~147 million metric tons annually in US~147 million metric tons annually in US– Worldwide ~2 billion metric tons.Worldwide ~2 billion metric tons.

Improving air quality in developed countries, Improving air quality in developed countries, developing getting worse.developing getting worse.

NATURAL SOURCES OF AIR NATURAL SOURCES OF AIR POLLUTIONPOLLUTION

Natural Fires - SmokeNatural Fires - Smoke Volcanoes - Ash and acidic componentsVolcanoes - Ash and acidic components Sea Spray - SulfurSea Spray - Sulfur Bacterial Metabolism - MethaneBacterial Metabolism - Methane DustDust PollenPollen

HUMAN-CAUSED AIR HUMAN-CAUSED AIR POLLUTIONPOLLUTION

Primary Pollutants – emitted directly into air Primary Pollutants – emitted directly into air from a point sourcefrom a point source

Secondary Pollutants – formed in air when Secondary Pollutants – formed in air when primary pollutants react or interactprimary pollutants react or interact

Major Sources of Primary PollutantsMajor Sources of Primary Pollutants

Stationary SourcesStationary Sources Combustion of fuels for power and heat – Power PlantsCombustion of fuels for power and heat – Power Plants Burning wood, crops, and/or forest firesBurning wood, crops, and/or forest fires IndustryIndustry Solvents and aerosolsSolvents and aerosols

Mobile SourcesMobile Sources Highway: cars, trucks, buses and motorcyclesHighway: cars, trucks, buses and motorcycles Off-highway: aircraft, boats, locomotives, farm Off-highway: aircraft, boats, locomotives, farm

equipment, RVs, construction machinery, and lawn equipment, RVs, construction machinery, and lawn mowersmowers

Major Air PollutantsMajor Air Pollutants

• Carbon monoxide (CO)

• Nitrogen dioxides (NO2)

• Ozone (O3)

• Particulate matter (PM-10, PM-2.5)

• Sulfur dioxide (SO2)

• Lead (Pb)

• Greenhouse gases (CO2 and others)

Carbon MonoxidesCarbon Monoxides PropertiesProperties:: colorless, odorless, 0.0036% of colorless, odorless, 0.0036% of

atmosphereatmosphere EffectsEffects:: reduces ability of blood to bring oxygen to reduces ability of blood to bring oxygen to

body cells and tissues, body cells and tissues, mental functions and visual mental functions and visual acuity, even at low levelsacuity, even at low levels

Sources:Sources: incomplete combustion of fossil fuels incomplete combustion of fossil fuels – 60 - 95% from auto exhaust60 - 95% from auto exhaust

5.5 billion tons enter atmosphere/year5.5 billion tons enter atmosphere/year

Sulfur DioxidesSulfur Dioxides PropertiesProperties:: colorless gas with irritating odor colorless gas with irritating odor EffectsEffects:: produces acid rain (H produces acid rain (H22SOSO44), breathing ), breathing

difficulties, eutrophication due to sulfate formationdifficulties, eutrophication due to sulfate formation SourcesSources::

– Natural: sea spray, volcanic fumes Natural: sea spray, volcanic fumes – Human sources: Human sources: burning high sulfur coal or oil, burning high sulfur coal or oil,

smelting or metals, paper manufacturesmelting or metals, paper manufacture

Particulate MatterParticulate Matter

PropertiesProperties:: particles suspended in air particles suspended in air (<10 um)(<10 um)

EffectsEffects:: lung damage, mutagenic, carcinogenic, lung damage, mutagenic, carcinogenic, teratogenic, reduces visibilityteratogenic, reduces visibility

Sources:Sources: –Natural: dust, volcanic ash, pollen, sporesNatural: dust, volcanic ash, pollen, spores–Human sources: Human sources: Smoke, dust, soot, asbestos, factories,

unpaved roads, plowing, lint, burning fields

Particulate MatterParticulate Matter• Impacts: Visibility at Shenandoah Nat’l Park

Source: Ref. (2)

Nitrogen OxidesNitrogen Oxides PPropertiesroperties:: reddish brown gas, strong oxidizing reddish brown gas, strong oxidizing

agent, forms Nitric acid in airagent, forms Nitric acid in air EffectsEffects:: acid rain, lung and heart problems, acid rain, lung and heart problems,

decreased visibility (yellow haze), suppresses plant decreased visibility (yellow haze), suppresses plant growthgrowth

SourcesSources:: – Natural: forest fires, volcanoes, lightning, bacteria in Natural: forest fires, volcanoes, lightning, bacteria in

soilsoil– Human sources: fossil fuels combustion, power plants, Human sources: fossil fuels combustion, power plants,

LeadLead PropertiesProperties:: grayish metal grayish metal EffectsEffects:: accumulates in tissue; affects kidneys, accumulates in tissue; affects kidneys,

liver and nervous system (children most liver and nervous system (children most susceptible); mental retardation; possible susceptible); mental retardation; possible carcinogen; 20% of inner city kids have [high]carcinogen; 20% of inner city kids have [high]

SourcesSources:: particulates, smelters, batteries particulates, smelters, batteries 2 million tons enter atmosphere/year2 million tons enter atmosphere/year

Ozone (Ground Level)Ozone (Ground Level)

PropertiesProperties:: colorless, unpleasant odor, major part of colorless, unpleasant odor, major part of photochemical smogphotochemical smog

EffectsEffects:: lung irritant, damages plants, rubber, fabric, lung irritant, damages plants, rubber, fabric, eye, reduces visibilityeye, reduces visibility

SourcesSources:: Created by sunlight acting on NO Created by sunlight acting on NOxx and VOCs and VOCs NOx + VOCs + sunlight -> NOx + O3

cars, industry, gas vapors, chemical solvents, cars, industry, gas vapors, chemical solvents, incomplete fuel combustion productsincomplete fuel combustion products

Ozone (OOzone (O33)) 10,000 to 15,000 people in US admitted to 10,000 to 15,000 people in US admitted to

hospitals each year due to ozone-related illnesshospitals each year due to ozone-related illness Children more susceptibleChildren more susceptible

VOCsVOCs PropertiesProperties:: organic compounds (hydrocarbons) that organic compounds (hydrocarbons) that

evaporate easily, usually aromatic evaporate easily, usually aromatic EffectsEffects:: eye and respiratory irritants; carcinogenic; eye and respiratory irritants; carcinogenic;

liver, CNS, or kidney damage; damages plants; lowered liver, CNS, or kidney damage; damages plants; lowered visibility due to brown haze; global warmingvisibility due to brown haze; global warming

Sources:Sources: vehiclesvehicles (largest source),(largest source), evaporation of evaporation of solvents or fossil fuels, aerosols, paint thinners, dry solvents or fossil fuels, aerosols, paint thinners, dry cleaningcleaning

Concentrations indoors up to 1000x outdoorsConcentrations indoors up to 1000x outdoors 600 million tons of CFCs 600 million tons of CFCs

Formation & IntensityFactors Local climate (inversions, air pressure, temperature,

humidity) Topography (hills and mountains) Population density Amount of industry Fuels used by population and industry for heating,

manufacturing, transportation, power Weather: rain, snow,wind Buildings (slow wind speed) Mass transit used Economics

...when polluted air is stagnant (weather conditions, geographic location)

Los Angeles, CA

Smog FormsSmog Forms

Primary PollutantsPrimary Pollutants

Secondary PollutantsSecondary Pollutants

SourcesSourcesNaturalNaturalStationaryStationary

COCO COCO22

SOSO22 NONO NONO22

Most hydrocarbonsMost hydrocarbons

Most suspendedMost suspendedparticlesparticles

SOSO33

HNOHNO33 HH22SOSO44

HH22OO22 OO33 PANsPANs

MostMost andand saltssaltsNONO33––

MobileMobile

SOSO4422 ––

Photochemical SmogPhotochemical Smog

Primary Pollutants

NO2 + Hydrocarbons

Auto Emissions

UV radiation

H2O + O2

Secondary Pollutants

HNO3 O3

nitric acid ozone

Photochemical Smog

Temperature InversionsTemperature Inversions

Occurs when a stable layer of warm air overlay Occurs when a stable layer of warm air overlay cooler air near the groundcooler air near the ground– Usually happens at night since ground loses heat Usually happens at night since ground loses heat

quicklyquickly

Heat IslandsHeat Islands

Heat islands-Urban development creates warm, Heat islands-Urban development creates warm, stable air masses over large cities.stable air masses over large cities.– Sparse vegetation and dark surfacesSparse vegetation and dark surfaces– Concentrates pollutants in a “dust dome”.Concentrates pollutants in a “dust dome”.

Rural areas downwind have decreased visibility and Rural areas downwind have decreased visibility and increased rainfall.increased rainfall.

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Acid DepositionAcid Deposition• Occurs when sulfur dioxide and nitrogen oxides are Occurs when sulfur dioxide and nitrogen oxides are

emitted into the atmosphere emitted into the atmosphere – Coal burning plantsCoal burning plants– Automobiles Automobiles

• Absorbed by water droplets in clouds Absorbed by water droplets in clouds

Fossil fuelsPower plants

Industrial emissionsAuto emissions

Primary PollutantsSO2

Secondary Pollutants

H2SO4 HNO2

sulfuric acid nitric acid

soilsleaching of minerals

vegetationdirect toxicity

indirect health effects

sedimentsleaching aluminum

acidic precipitation

2 Forms of Acid Deposition2 Forms of Acid Deposition

Wet deposition-acidic rain, fog, snow and cloud Wet deposition-acidic rain, fog, snow and cloud vaporvapor– Falls in downward winds areas within 4-14 daysFalls in downward winds areas within 4-14 days

Dry deposition-acidic particles and gasesDry deposition-acidic particles and gases– Falls near the emission sources within 2-3 daysFalls near the emission sources within 2-3 days

Transformation tosulfuric acid (H2SO4)

and nitric acid (HNO3)

Nitric oxide (NO)

Acid fog

Sulfur dioxide (SO2)and NO

Windborne ammonia gasand particles of cultivated soilpartially neutralize acids and

form dry sulfate and nitrate salts

Dry aciddeposition

(sulfur dioxidegas and particles

of sulfate andnitrate salts)

Lakes indeep soil

high in limestoneare buffered

Lakes in shallowsoil low inlimestonebecomeacidic

Wet acid deposition(droplets of H2SO4 andHNO3 dissolved in rain

and snow)

AcidicAcidicPrecipitationPrecipitation

Factors that effect…Factors that effect…

• The strength of the effects depend on many The strength of the effects depend on many factorsfactors– How acidic the water isHow acidic the water is– The chemistry and buffering capacity of The chemistry and buffering capacity of

the soils involvedthe soils involved– The types of fish, trees, and other living The types of fish, trees, and other living

things that rely on the waterthings that rely on the water

Effects of Acid RainEffects of Acid Rain• Damages forests and soils, fish and other Damages forests and soils, fish and other

organisms, materials, and human health.organisms, materials, and human health.• most clearly seen in the aquatic environmentsmost clearly seen in the aquatic environments

• young of most species are more sensitiveyoung of most species are more sensitive• At pH 5, most fish eggs cannot hatch. At pH 5, most fish eggs cannot hatch. • At lower pH levels, some adult fish die.At lower pH levels, some adult fish die.

Effects of Acid Rain Effects of Acid Rain • Acidic water Acidic water

– dissolves the nutrients and helpful minerals dissolves the nutrients and helpful minerals in the soil in the soil

– washes them away before trees and other washes them away before trees and other plants can use them to growplants can use them to grow

Buffering CapacityBuffering Capacity

• Acid rain primarily affects sensitive bodies of waterAcid rain primarily affects sensitive bodies of water• soils have a limited “buffering capacity”soils have a limited “buffering capacity”

• Lakes and streams become acidicLakes and streams become acidic

• In areas where buffering capacity is low, acid rain also releases aluminum from In areas where buffering capacity is low, acid rain also releases aluminum from soils into lakes and streamssoils into lakes and streams• Aluminum is highly toxic to many species of aquatic organisms.Aluminum is highly toxic to many species of aquatic organisms.

GermanyGermanyMongoliaMongolia

Great Smoky Mountains, NC

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Ozone – Two FacesOzone – Two Faces• Stratosphere – Good OzoneStratosphere – Good Ozone

–Blocks UV radiationBlocks UV radiation–Hole caused by depletion due to Hole caused by depletion due to

CFC’sCFC’s

• Troposphere – Bad OzoneTroposphere – Bad Ozone–Pollution Pollution

• Photochemical smogPhotochemical smog

• Eye irritantEye irritant

Ozone FormationOzone Formation

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Destroying Good OzoneDestroying Good Ozone

• Chloroflourocarbons created in 1928 as non-toxic, non-Chloroflourocarbons created in 1928 as non-toxic, non-flamable refrigerantsflamable refrigerants• first produced commercially in the 1930's by DuPontfirst produced commercially in the 1930's by DuPont

• In 1974, a laboratory study demonstrated the ability of In 1974, a laboratory study demonstrated the ability of CFC's to breakdown Ozone in the presence of high CFC's to breakdown Ozone in the presence of high frequency UV lightfrequency UV light

• Cl + OCl + O33 -> ClO + O -> ClO + O22 ClO + O ClO + O33 ---> 2 O ---> 2 O22 + Cl + Cl• In a 1985, a study summarized data that had been collected In a 1985, a study summarized data that had been collected

by the British Antartic Survey showing that ozone levels by the British Antartic Survey showing that ozone levels had dropped to 10% below normal January levels for had dropped to 10% below normal January levels for Antarctica.Antarctica.

• http://www.nas.nasa.gov/About/Education/Ozone/history.html

Destruction of Stratospheric OzoneDestruction of Stratospheric Ozone

•CFCs persist up in the atmosphere for decades

•Models indicate that 75-85% of the observed ozone losses in the stratosphere since 1976 are the result of ozone depleting chemicals released in the early 1950s

404040 http://www.mmscrusaders.com/newscirocks/ozone/cfc.jpg

Stratospheric OzoneStratospheric Ozone

Winds isolate Antarctic air and allows Winds isolate Antarctic air and allows stratospheric temperatures to drop and create ice stratospheric temperatures to drop and create ice crystals at high altitudes.crystals at high altitudes.– ozone and chlorine molecules are absorbed on the ozone and chlorine molecules are absorbed on the

surfaces of these ice particles.surfaces of these ice particles. When sun returns in the spring and provides energy When sun returns in the spring and provides energy

chlorine molecules are releasedchlorine molecules are released

Harmful effects of UV radiationHarmful effects of UV radiation

Skin cancerSkin cancer Cataracts and sun burningCataracts and sun burning Adverse impact on crops and animalsAdverse impact on crops and animals Alters photochemical reaction rates Increases smog and surface layer ozone Degradation of paints and plastic materialDegradation of paints and plastic material

Montreal ProtocolMontreal Protocol An international treaty designed to protect the ozone An international treaty designed to protect the ozone

layer layer Phasing out production of number of substances Phasing out production of number of substances

believed to be responsible for ozone depletionbelieved to be responsible for ozone depletion Effective January 1, 1989Effective January 1, 1989

– Five revisionsFive revisions• 1990 (London)1990 (London)

• 1992 (Copenhagen)1992 (Copenhagen)

• 1995 (Vienna)1995 (Vienna)

• 1997 (Montreal)1997 (Montreal)

• 1999 (Beijing)1999 (Beijing)

As a result CFC production fell 85%As a result CFC production fell 85%

Global Warming…What is it?Global Warming…What is it?

Global Warming refers to an average increase in Global Warming refers to an average increase in the Earth's temperature,the Earth's temperature,– Which in turn causes changes in climateWhich in turn causes changes in climate– Caused by the GREENHOUSE EFFECTCaused by the GREENHOUSE EFFECT

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Greenhouse GasesGreenhouse Gases

The greenhouse gases contribute to holding heat inside The greenhouse gases contribute to holding heat inside our atmosphere.our atmosphere.

They include:They include:– carbon dioxide (COcarbon dioxide (CO22))– methane (CHmethane (CH44))– nitrous oxide (Nnitrous oxide (N22O)O)– chlorofluorocarbons (CFCs)chlorofluorocarbons (CFCs)– ozone (Oozone (O33) ) – water vaporwater vapor

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Global Warming• Current Causes

– Deforestation

– Greenhouse Gases• Burning of Fossil Fuels

• Main villain is currently Carbon Dioxide (CO2)

• China leader (~21%)

• US 2nd runner up (~19%)

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Deforestation - USDeforestation - US• About one half of About one half of

the forests that the forests that covered the Earth covered the Earth are gone are gone

• Since 1600, 90% Since 1600, 90% of the U.S. forests of the U.S. forests have been cleared have been cleared awayaway

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Results of DeforestationResults of Deforestation• Loss of trees’ ability to remove CO2 • Decaying trees release CO2 and methane • Fallen trees are often burnt which releases

CO2 • Deforestation the largest source of emissions in

developing countries

Current EvidenceCurrent Evidence

COCO2 2 and temperatureand temperature

– Measured by analyzing radioisotopes in rocks, Measured by analyzing radioisotopes in rocks, fossils, ocean sediments, ice coresfossils, ocean sediments, ice cores

Temperature change (blue) and carbon dioxide change (red) observed in ice core records

55http://web.mit.edu/12.000/www/m2011/finalwebsite/graphics/climate/tempmap1.png

EvidenceEvidence COCO22 and Temperature and Temperature

GlaciersGlaciers

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GlaciersGlaciers• Have been shrinking throughout the Have been shrinking throughout the

20th Century20th Century

• Loss of glaciers in South America Loss of glaciers in South America and Asia glaciers is particularly and Asia glaciers is particularly rapid and will threaten the water rapid and will threaten the water supplies of millions of peoplesupplies of millions of people

GlaciersGlaciers Polar IcePolar Ice

– Arctic, Antarctic, GreenlandArctic, Antarctic, Greenland

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Arctic Ice• Perennial ice may be 10 or more feet thick

• New ice is only one to seven feet thick

• Since 1970 a 10% loss of ice cover per decade

Sept. 21, 1979 and Sept. 14, 2007

Energy and the Greenhouse Energy and the Greenhouse EffectEffect

Surfaces that reflect energy have a highSurfaces that reflect energy have a high albedo albedo (Reflectivity).(Reflectivity).– Fresh clean snow Fresh clean snow 90% 90%– Dark soil Dark soil 3%3%– Net average of earth Net average of earth 30%30%

Albedo EffectAlbedo Effect

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PermafrostPermafrost• About 10% of Earth’s surface has permafrostAbout 10% of Earth’s surface has permafrost

• In the last 11,000 years, the permafrost has In the last 11,000 years, the permafrost has not thawed not thawed – None None of the vegetation has decayedof the vegetation has decayed

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PermafrostPermafrost• Alaska permafrost Alaska permafrost

temperature has increased temperature has increased 0.5° to 1.5° C since 1980, 0.5° to 1.5° C since 1980,

• Serious effects include Serious effects include – forest damageforest damage– sinking roads and buildingssinking roads and buildings– eroding tundra riverbankseroding tundra riverbanks– changes in tundra vegetationchanges in tundra vegetation– increased carbon dioxide increased carbon dioxide

and methane emissions from and methane emissions from thawed peat. thawed peat.

68http://benmuse.typepad.com/ben_muse/images/2007/10/10/sinkhole_5.png

69http://www.global-greenhouse-warming.com/images/PermafrostDrunkenForest.jpg

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PermafrostPermafrost• A University of Alaska at A University of Alaska at

Fairbanks team found that the Fairbanks team found that the permafrost gave off five times permafrost gave off five times as much methane as previously as much methane as previously estimated estimated

• Defrosting could release nearly Defrosting could release nearly 1,000 gigatons of carbon stored 1,000 gigatons of carbon stored and hasten global warming. and hasten global warming.

– 10 to 25% increase in 10 to 25% increase in global warmingglobal warming

GlaciersGlaciers Polar IcePolar Ice

– ArcticArctic

– AntarcticAntarctic

– GreenlandGreenland

Weather SeverityWeather Severity– Droughts, hurricanes, tropical stormsDroughts, hurricanes, tropical storms

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EvidenceEvidence• COCO22 and Temperature and Temperature

• GlaciersGlaciers

• Polar IcePolar Ice– ArcticArctic

– AntarcticAntarctic

– GreenlandGreenland

• Weather SeverityWeather Severity

• Biome ChangesBiome Changes

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Oceans absorb COOceans absorb CO22

• COCO22 in water makes in water makes

Carbonic AcidCarbonic Acid

• Greater acidity of oceans is Greater acidity of oceans is bleaching coralbleaching coral

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ConsequenceConsequence• Cold EuropeCold Europe

• Increased melting from Greenland could dilute Increased melting from Greenland could dilute ocean water and stop the water from sinking near ocean water and stop the water from sinking near Greenland and shut off the mixing of the watersGreenland and shut off the mixing of the waters

Antarctica

GreenlandGreenland

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ConsequenceConsequence• Cold Europe Cold Europe

• Increased SmogIncreased Smog

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• Spread of Tropical DiseaseSpread of Tropical Diseasess

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• Spread of Tropical DiseasesSpread of Tropical Diseases

• Changes in BiodiversityChanges in Biodiversity

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Changes in BiodiversityChanges in Biodiversity

"It is not the strongest of the "It is not the strongest of the species that survive, nor the most species that survive, nor the most

intelligent, but the most responsive intelligent, but the most responsive to change."to change."

Charles Darwin, 1835Charles Darwin, 1835

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Changes in BiodiversityChanges in BiodiversityBiomes

Shift of Alpine biomes up mountains and further North/South

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Die-offs Coral bleaching die-offs of up to 50% in the Indian Ocean

Biomes Shift of Alpine biomes up mountains and

further North/South

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Dire prediction for Dire prediction for world's coral reefsworld's coral reefs

POSTED: 1404 GMT (2204 HKT), October 25, 2006 POSTED: 1404 GMT (2204 HKT), October 25, 2006 CHARLOTTE AMALIE, U.S. Virgin IslandsCHARLOTTE AMALIE, U.S. Virgin Islands (AP) (AP)

Researchers fear more than half the world's coral Researchers fear more than half the world's coral reefs could die in less than 25 years and say global reefs could die in less than 25 years and say global warming may at least be partly to blame.warming may at least be partly to blame.Sea temperatures are rising, weakening the reefs' resistance to increased pollutants, such Sea temperatures are rising, weakening the reefs' resistance to increased pollutants, such as runoff from construction sites and toxins from boat paints. The fragile reefs are hosts to as runoff from construction sites and toxins from boat paints. The fragile reefs are hosts to countless marine plants and animals.countless marine plants and animals."Think of it as a high school chemistry class," said Billy Causey, the Caribbean and Gulf Mexico director of the National Oceanic and Atmospheric "Think of it as a high school chemistry class," said Billy Causey, the Caribbean and Gulf Mexico director of the National Oceanic and Atmospheric Administration.Administration."You mix some chemicals together and nothing happens. You crank up the Bunsen burner and all of a sudden things start bubbling around. That's what's "You mix some chemicals together and nothing happens. You crank up the Bunsen burner and all of a sudden things start bubbling around. That's what's happening. That global Bunsen burner is cranking up."happening. That global Bunsen burner is cranking up."Causey was one of some 200 private and government researchers from the Caribbean, Florida and U.S. Pacific islands who gathered in St. Thomas for a meeting of Causey was one of some 200 private and government researchers from the Caribbean, Florida and U.S. Pacific islands who gathered in St. Thomas for a meeting of the NOAA's U.S. Coral Reef Task Force.the NOAA's U.S. Coral Reef Task Force.Last year's coral loss in the Caribbean waters supports predictions that 60 percent of the world's coral could die within a quarter century, said Tyler Smith of the Last year's coral loss in the Caribbean waters supports predictions that 60 percent of the world's coral could die within a quarter century, said Tyler Smith of the University of the Virgin Islands.University of the Virgin Islands."Given current rates of degradation of reef habitats, this is a plausible prediction," Smith said."Given current rates of degradation of reef habitats, this is a plausible prediction," Smith said.More than 47 percent of the coral in underwater study sites covering 31 acres around the U.S. Virgin Islands died after sea temperatures exceeded the norm for More than 47 percent of the coral in underwater study sites covering 31 acres around the U.S. Virgin Islands died after sea temperatures exceeded the norm for three months in 2005, said Jeff Miller, a scientist with the Virgin Islands National Park.three months in 2005, said Jeff Miller, a scientist with the Virgin Islands National Park.The unusual warm water can stress coral, causing it to lose its pigment and making it more vulnerable to disease.The unusual warm water can stress coral, causing it to lose its pigment and making it more vulnerable to disease.This year, Caribbean coral narrowly avoided another widespread episode of bleaching when sea temperatures briefly surpassed levels considered healthy for reefs.This year, Caribbean coral narrowly avoided another widespread episode of bleaching when sea temperatures briefly surpassed levels considered healthy for reefs.Up to 30 percent of the world's coral reefs have died in the last 50 years, and another 30 percent are severely damaged, said Smith, who studies coral health in the Up to 30 percent of the world's coral reefs have died in the last 50 years, and another 30 percent are severely damaged, said Smith, who studies coral health in the U.S. Virgin Islands and collaborates with researchers globally.U.S. Virgin Islands and collaborates with researchers globally."U.S. Virgin Islands coral today is likely at its lowest levels in recorded history," Smith said."U.S. Virgin Islands coral today is likely at its lowest levels in recorded history," Smith said.The researchers said global warming was a potential cause of the abnormally high sea temperatures but was not the only suspect in the reefs' demise.The researchers said global warming was a potential cause of the abnormally high sea temperatures but was not the only suspect in the reefs' demise.What causes disease in coral can be hard to pinpoint and could be a combination of things. Other threats include silt runoff from construction sites, which prevents What causes disease in coral can be hard to pinpoint and could be a combination of things. Other threats include silt runoff from construction sites, which prevents the coral from getting enough sunlight, and a record increase in fleshy, green algae, which competes with coral for sunlight.the coral from getting enough sunlight, and a record increase in fleshy, green algae, which competes with coral for sunlight."Climate change is an important factor that is influencing coral reefs worldwide," said Mark Eakin, director of NOAA's Coral Reef Watch. "It adds to the other "Climate change is an important factor that is influencing coral reefs worldwide," said Mark Eakin, director of NOAA's Coral Reef Watch. "It adds to the other problems that we are having."problems that we are having."

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Ocean acidification due to Ocean acidification due to increasing atmospheric carbon increasing atmospheric carbon dioxidedioxide30 Jun 2005 30 Jun 2005

Carbon dioxide (COCarbon dioxide (CO22) emitted to the atmosphere by human ) emitted to the atmosphere by human

activities is being absorbed by the oceans, making them more activities is being absorbed by the oceans, making them more acidic (lowering the pH the measure of acidity).acidic (lowering the pH the measure of acidity).

Evidence indicates that emissions of carbon dioxide from Evidence indicates that emissions of carbon dioxide from human activities over the past 200 years have already led to a human activities over the past 200 years have already led to a reduction in the average pH of surface seawater of 0.1 units reduction in the average pH of surface seawater of 0.1 units and could fall by 0.5 units by the year 2100. This pH is and could fall by 0.5 units by the year 2100. This pH is probably lower than has been experienced for hundreds of probably lower than has been experienced for hundreds of millennia and, critically, at a rate of change probably 100 millennia and, critically, at a rate of change probably 100 times greater than at any time over this period.times greater than at any time over this period.The report outlines our best understanding of the impacts of these chemical changes on the oceans. The impacts will be greater for The report outlines our best understanding of the impacts of these chemical changes on the oceans. The impacts will be greater for some regions and ecosystems, and will be most severe for coral reefs and the Southern Ocean. The impacts of ocean acidification some regions and ecosystems, and will be most severe for coral reefs and the Southern Ocean. The impacts of ocean acidification on other marine organisms and ecosystems are much less certain. We recommend a major international research effort be on other marine organisms and ecosystems are much less certain. We recommend a major international research effort be launched into this relatively new area of research.launched into this relatively new area of research.

We recommend that action needs to be taken now to reduce global emissions of COWe recommend that action needs to be taken now to reduce global emissions of CO22 from human activities to the atmosphere to from human activities to the atmosphere to

avoid the risk of irreversible damage from ocean acidification.avoid the risk of irreversible damage from ocean acidification.

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Acidification may also directly affect the Acidification may also directly affect the growth and growth and reproduction rates of fishreproduction rates of fish, as well as affecting the , as well as affecting the plankton populations which they rely on for foodplankton populations which they rely on for food , , with potentially disastrous consequences for marine food with potentially disastrous consequences for marine food webs. webs. In addition, nutrient concentrations in surface waters of In addition, nutrient concentrations in surface waters of high-latitude regions are likely to fall, subsurface waters high-latitude regions are likely to fall, subsurface waters become less oxygenated, and phytoplankton will experience become less oxygenated, and phytoplankton will experience increased exposure to sunlight. increased exposure to sunlight. This could affect multiple marine species and change the This could affect multiple marine species and change the composition of biological communities in ways that are not composition of biological communities in ways that are not yet understood.yet understood.

Probe into rising ocean Probe into rising ocean acidityacidity Tuesday, 17 August, 2004Tuesday, 17 August, 2004

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Die-offs

Extinctions

Coral bleaching die-offs of up to 50% in the Indian Ocean

Golden Toads, Harlequin Frogs, ...

further North/South

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Global Warming Already Causing Global Warming Already Causing Extinctions, Scientists SayExtinctions, Scientists Say

Hannah Hoag for Hannah Hoag for National Geographic NewsNational Geographic News November 28, 2006 November 28, 2006

• In Costa Rica about 2/3 of the 110 known In Costa Rica about 2/3 of the 110 known Harlequin frog species are extinctHarlequin frog species are extinct

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• In Antarctica, the Adélie penguin on Litchfield In Antarctica, the Adélie penguin on Litchfield Island has disappeared. Island has disappeared.

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Die-offs

Extinctions

Life Cycles

Gothic marmots emerge from hibernation about a month earlier than 30 years ago

further North/South

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Die-offs

Extinctions

Life Cycles

Physiology

The average weight of adult female polar bears has decreased by more than 20% over

the last 25 years

further North/South

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• Polar bears depend on ice Polar bears depend on ice

• Without the ice, the polar bear will die

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Die-offs

Extinctions

Life Cycles

Physiology

The average weight of adult female polar bears has decreased by more than 20% over

the last 25 years

further North/South

Migration Multiple areas affected

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Routes farther NorthRoutes farther North

European Bee-Eaters (Merops apiaster) once very rare in Germany are now breeding regularly across the country.

The Rosy-Breasted Trumpeter Finch (Rhodopechys githaginea) is one of many birds once normally confined to arid North Africa and the Middle East now found in increasingly large numbers in southern Spain.

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Habitat ChangesHabitat ChangesPermafrost is thawing and Arctic tundra is being replaced by forest

Desertification is occurring in Africa

Sea levels are rising

Hurricanes are more frequent in the Caribbean

Antarctic waters are getting warmer and the ice is melting affecting sea salinity

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Habitat ChangesHabitat Changes

There is likely to be a general shift of species towards the poles, reducing the range of species most adapted to colder waters.

The Common Dolphin, a warm water species is increasing its range

The White-beaked Dolphin’s range is reducing.

Predators are following their prey as prey species (eg fish) change their mean latitude and/or depth.

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• Droughts and firesDroughts and fires

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• Droughts and firesDroughts and fires

• Sea levels riseSea levels rise

Sea Levels RiseSea Levels Rise

From:From: Melting glaciers and ice sheets on landMelting glaciers and ice sheets on land As water of the oceans warms, it expandsAs water of the oceans warms, it expands

– Since 1870 have risen 9 inchesSince 1870 have risen 9 inches

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U.S. East Coast during Ice Age - 20,000 years ago (400 feet below today)U.S. East Coast during Ice Age - 20,000 years ago (400 feet below today)

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U.S. East Coast – if West sheet or Greenland melted (17-foot)U.S. East Coast – if West sheet or Greenland melted (17-foot)

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U.S. East Coast – if East sheet melted (170-foot) U.S. East Coast – if East sheet melted (170-foot)

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Florida Florida during Ice Ageduring Ice Age - 20,000 years ago (400 feet below today) - 20,000 years ago (400 feet below today)

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Florida – if West sheet or Greenland melted (17-foot rise) Florida – if West sheet or Greenland melted (17-foot rise)

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Florida – if East sheet melted (170-foot/50m rise)Florida – if East sheet melted (170-foot/50m rise)

Positive FeedbackPositive Feedback

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Positive FeedbackPositive Feedback• Oceans currents and COOceans currents and CO22 levels levels

– Cold deep resurface and emit COCold deep resurface and emit CO22

• Permafrost meltingPermafrost melting– COCO22 and methane released by decomposition and methane released by decomposition

• Arctic ice meltingArctic ice melting– Less reflection of sunlight – water and land Less reflection of sunlight – water and land

heat upheat up

• DesertificationDesertification– Soil dries out and releases COSoil dries out and releases CO22

Air Pollution

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