human impact on the biosphere ecosystems as affected by human activity
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Human Impact on Human Impact on the Biospherethe Biosphere
Ecosystems as affected by Ecosystems as affected by Human activityHuman activity
Human ImpactsHuman Impacts
Humans are using energy and altering Humans are using energy and altering
the environment at astonishing ratesthe environment at astonishing rates
We are altering natural processes before We are altering natural processes before
we even understand themwe even understand them
PollutantsPollutants
Substances with which an ecosystem Substances with which an ecosystem
has had no prior evolutionary experiencehas had no prior evolutionary experience
No adaptive mechanisms are in place to No adaptive mechanisms are in place to
deal with themdeal with them
Air PollutantsAir Pollutants
Carbon oxidesCarbon oxides
Sulfur oxidesSulfur oxides
Nitrogen oxidesNitrogen oxides
Volatile organic compoundsVolatile organic compounds
Photochemical oxidantsPhotochemical oxidants
Suspended particlesSuspended particles
Industrial SmogIndustrial Smog
Gray-air smogGray-air smog
Forms over cities that burn large amounts Forms over cities that burn large amounts
of coal and heavy fuel oils; mainly in of coal and heavy fuel oils; mainly in
developing countriesdeveloping countries
Main components are sulfur oxides and Main components are sulfur oxides and
suspended particlessuspended particles
Photochemical smogPhotochemical smog
Brown-air smog Brown-air smog
Forms when sunlight interacts with Forms when sunlight interacts with
components from automobile exhaust components from automobile exhaust
Nitrogen oxides are the main culpritsNitrogen oxides are the main culprits
Hot days contribute to formationHot days contribute to formation
Thermal InversionThermal Inversion
Weather pattern in which a layer of cool, Weather pattern in which a layer of cool, dense air is trapped beneath a layer of dense air is trapped beneath a layer of warm airwarm air
cool air
warm inversion air
cool air
Acid DepositionAcid Deposition
Caused by the Caused by the
release of sulfur and release of sulfur and
nitrogen oxidesnitrogen oxides
Coal-burning power Coal-burning power
plants and motor plants and motor
vehicles are major vehicles are major
sourcessources
Ozone ThinningOzone Thinning
In early spring and In early spring and
summer ozone layer summer ozone layer
over Antarctica thinsover Antarctica thins
Seasonal loss of Seasonal loss of
ozone is at highest ozone is at highest
level ever recordedlevel ever recorded
SouthAmerica
Antarctica
Effect of Ozone ThinningEffect of Ozone Thinning
Increased amount of Increased amount of UV radiationUV radiation
reaches Earth’s surfacereaches Earth’s surface
UV damages DNA and negatively UV damages DNA and negatively
affects human healthaffects human health
UV also affects plants, lowers UV also affects plants, lowers
primary productivityprimary productivity
Protecting the Ozone LayerProtecting the Ozone Layer
CFC productionCFC production has been halted in has been halted in
developed countries, will be phased out in developed countries, will be phased out in
developing countries developing countries
Even with bans it will take more than 50 Even with bans it will take more than 50
years for ozone levels to recoveryears for ozone levels to recover
Generating GarbageGenerating Garbage
Developed countries generate huge Developed countries generate huge
amounts of wasteamounts of waste
Paper products account for half the total Paper products account for half the total
volumevolume
Recycling can reduce pollutants, save Recycling can reduce pollutants, save
energy, ease pressure on landfillsenergy, ease pressure on landfills
DeforestationDeforestation
Removal of all trees from large tracts of Removal of all trees from large tracts of
landland
38 million acres logged each year38 million acres logged each year
Wood is used for fuel, lumberWood is used for fuel, lumber
Land is cleared for grazing or cropsLand is cleared for grazing or crops
Effects of DeforestationEffects of Deforestation
Increased leaching and soil erosionIncreased leaching and soil erosion
Increased flooding and Increased flooding and
sedimentation of downstream riverssedimentation of downstream rivers
Regional precipitation declinesRegional precipitation declines
Possible amplification of the Possible amplification of the
greenhouse effectgreenhouse effect
Regions of DeforestationRegions of Deforestation
Rates of forest loss are greatest in Brazil, Rates of forest loss are greatest in Brazil,
Indonesia, Mexico, and ColumbiaIndonesia, Mexico, and Columbia
Highly mechanized logging is proceeding Highly mechanized logging is proceeding
in temperate forests of the United States in temperate forests of the United States
and Canadaand Canada
Destroying BiodiversityDestroying Biodiversity
Tropical rainforests have the greatest Tropical rainforests have the greatest
variety of insects, most bird speciesvariety of insects, most bird species
Some tropical forest species may prove Some tropical forest species may prove
valuable to humansvaluable to humans
Our primate ancestors evolved in forests Our primate ancestors evolved in forests
like the ones we are destroying like the ones we are destroying
DesertificationDesertification
Conversion of large tracts of grassland to Conversion of large tracts of grassland to
desertlike conditions desertlike conditions
Conversions of cropland that result in Conversions of cropland that result in
more than 10 percent decline in more than 10 percent decline in
productivityproductivity
Ongoing DesertificationOngoing Desertification
Sahel region of Africa is undergoing rapid Sahel region of Africa is undergoing rapid
desertificationdesertification
Causes are overgrazing, overfarming, and Causes are overgrazing, overfarming, and
prolonged droughtprolonged drought
One solution may be to substitute native One solution may be to substitute native
herbivores for imported cattleherbivores for imported cattle
Water Use and ScarcityWater Use and Scarcity
Most of Earth’s water is too salty for Most of Earth’s water is too salty for
human consumptionhuman consumption
Desalinization is expensive and Desalinization is expensive and
requires large energy inputsrequires large energy inputs
Irrigation of crops is the main use of Irrigation of crops is the main use of
freshwaterfreshwater
Negative Effects of IrrigationNegative Effects of Irrigation
Salinization, mineral buildup in soilSalinization, mineral buildup in soil
Elevation of the water table and Elevation of the water table and
waterloggingwaterlogging
Depletion of aquifersDepletion of aquifers
Aquifer ProblemsAquifer Problems
Water PollutantsWater Pollutants
SewageSewage Animal wastesAnimal wastes FertilizersFertilizers PesticidesPesticides Industrial chemicalsIndustrial chemicals Radioactive materialRadioactive material Excess heat (thermal pollution) Excess heat (thermal pollution)
Wastewater TreatmentWastewater Treatment
Primary treatment Primary treatment Use of screens and settling tanksUse of screens and settling tanks Addition of chlorine to kill pathogensAddition of chlorine to kill pathogens
Secondary treatment Secondary treatment Microbes break down organic matterMicrobes break down organic matter
Tertiary treatment removes additional toxic Tertiary treatment removes additional toxic substances; rarely usedsubstances; rarely used
Energy UseEnergy Use
Only 10 percent of energy used in Only 10 percent of energy used in
developed countries is from developed countries is from
renewable sourcesrenewable sources
Less developed countries rely more Less developed countries rely more
heavily on renewable sources heavily on renewable sources
(primary biomass)(primary biomass)
Fossil FuelsFossil Fuels
Coal, oil, natural gasCoal, oil, natural gas
Main energy source of developed Main energy source of developed
countriescountries
Burning of fossil fuels contributes to Burning of fossil fuels contributes to
global warmingglobal warming
OilOil
Reserves are decliningReserves are declining
Many reserves are in ecologically fragile Many reserves are in ecologically fragile
wilderness areaswilderness areas
Environmental costs of extracting and Environmental costs of extracting and
transporting reserves from such areas are transporting reserves from such areas are
highhigh
CoalCoal
Extensive reserves existExtensive reserves exist
Mining is very destructiveMining is very destructive
Burning coal releases sulfur dioxides Burning coal releases sulfur dioxides
that cause acid depositionthat cause acid deposition
Nuclear EnergyNuclear Energy
Used extensively in some energy-Used extensively in some energy-poor developed countries…clean poor developed countries…clean production of energy.production of energy.
Controversial in the United StatesControversial in the United States Emits very few air pollutants but Emits very few air pollutants but
creates radioactive waste (must be creates radioactive waste (must be securely stored)securely stored)
Potential for meltdown ?? Potential for meltdown ??
Chernobyl Accident - 1986Chernobyl Accident - 1986
Core meltdown at a nuclear power plant in Core meltdown at a nuclear power plant in the Ukrainethe Ukraine
31 immediate deaths, radiation sickness 31 immediate deaths, radiation sickness and death for othersand death for others
Cloud of radiation spread by winds across Cloud of radiation spread by winds across EuropeEurope
Long-term health impacts downwindLong-term health impacts downwind
Solar-Hydrogen EnergySolar-Hydrogen Energy
Photovoltaic cells use sunlight energy Photovoltaic cells use sunlight energy
to split water to split water
Hydrogen gas produced in this way Hydrogen gas produced in this way
can be used as fuel or to generate can be used as fuel or to generate
electricityelectricity
Clean, renewable technologyClean, renewable technology
Wind EnergyWind Energy
An indirect use of solar energyAn indirect use of solar energy
Wind farms are arrays of turbinesWind farms are arrays of turbines
Can supplement needs of some Can supplement needs of some
regions but is not dependable regions but is not dependable
enough on it ownenough on it own
Fusion Fusion
Energy is released when atomic nuclei Energy is released when atomic nuclei fuse fuse
This process produces solar energyThis process produces solar energy Attempts to mimic this process on Earth Attempts to mimic this process on Earth
require use of lasers, magnetic fieldsrequire use of lasers, magnetic fields Not yet a commercially viable energy Not yet a commercially viable energy
sourcesource