Overview-of-global-environmental-problems

OverviewofglobalenvironmentalproblemsMarxoncesaid,donotoverlyintoxicatewiththejoyofconqueringnature,everytimehumanconquernature,naturewillrevengetous.”ItprovedthatMarxwasright.Sincethesecondindustrialrevolution,globalenvironmentalproblemsbrokeoutoneafteranother.Accordingtodifferentenvironmentalmedia,globalenvironmentalproblemscanbedividedintofourcategories：atmosphericenvironmentalproblems(climatechange,ozonedestruction,acidrainandairpollution),waterenvironmentalproblems(waterbodypollutionandmarinepollution),solidwasteenvironmentalproblems(solidwastepollutionandpoisonousandharmfulchemicalspollution),andeco-environmentalproblems(landdesertificationandlossofbiologicaldiversity).Alltheseenvironmentalproblemsmentionedarethesocalled“TopTenGlobalEnvironmentalProblems”,inwhichatmosphericenvironmentalproblemsarethemostserious,includingclimatechange,ozonedestruction,acidrainandairpollution.Climatechangeiscausedbyreleasingofcarbondioxide(CO2),methane(CH4),nitrousoxide(N2O),chlorofluorocarbons(CFCS),carbontetrachloride(CCl4),carbonmonoxide(CO)andothergreenhousegasesintotheatmospherebyincreasingscaleofhumanproductionactivities.Duringthepastcentury,averageglobaltemperaturesroseby0.6℃.Expertspredictthat,fromnowto2100,thegrowthrateofglobalaveragetemperatureismostlikelytobe1.8℃~4℃,andthesea-levelriserangeis18cmto59cm.Thereisapossibilityof90%thatthereasonscontributingtothistrendarehumanactivities.AccordingtotheIPCCthirdreport(IPCC,2001),theglobalatmosphericCO2concentrationwas379ppm,thehighestduringthepast650,000years.Obviously,climatechangeisthemostseriousglobalenvironmentalproblemshumanhavetoface.Ozonedestructionisalsoaglobalatmosphericproblemattractmuchattention.Itismagicalthatthereexistsathicknessofabout3mmlayerofozone25kmawayfromearthsurface.Itcanabsorbthesun'sultravioletrays,astheEarth'sprotectiveumbrellatoprotectlifeonEarthfromharmfulultravioletrays;whiletheenergystoredintheupperatmosphere,playsanimportantroleinregulatingclimate.Accordingtosatellitedata,theglobaltotalozonedecreasedbyroughly3%from1979–1990.TheozonedepletionneartheSouthPoleisparticularlyserious,about30-40%percentlowerthantheglobalaverageozone.Ozonedestructionwillincreasetheultravioletradiationintensityonground,whichleadagreatharmoflifeonearth.StudiesshowthatultravioletradiationcouldcausedamagetobiologicalproteinsandgeneticmaterialDNA,resultingincelldeath;thehigherincidenceofskincancerinhumans;damagetheeyes,resultinginblindnessleavingcataracts;endangeringaquaticfoodchainandasourceoffreeoxygen,affectingtheecologicalbalanceandself-purificationcapacityofwaterbodies.Acidrainreferstotheatmosphericprecipitationwhoseacidity(PHvalue)islessthan5.6.Acidraincouldaffecthumanenvironmentinmanyaspects,suchaspreventingwaterfish,shrimpgrowthwhenacidrainfallingintorivers,lakes,resultinginreducedorextinctfish;leadingtosoilacidification,destructionofsoilnutrients,harmingplantgrowth,resultingincropproduction,endangerforestgrowth.Therearethreebigacidrainareasintheworldcurrently,andacidraininsouthChinaistheonlyonethathasnotbeengoverned.Airpollutionmainlycausedbysuspendedparticles,carbonmonoxide,ozone,carbondioxide,nitrogenoxides,etc.Airpollutioncauses30-70millionpeopledieprematurelybecauseofdustpollutioneveryyear,25millionchildrensufferfromchroniclaryngitis,and4000-7000thousandsruralwomenandchildrensuffer.Amongalltheairpollutants,PM2.5(particleswithaerodynamicdiameterlessthan2.5um)arethemostharmful,andcausemoreandmorepublicattention.Waterisourdailyneeds,oneofthesubstanceswehumancontact.However,waternowhasbecomedangerous.Riverwaterpollutioncausednitrogenandphosphorusincreasingby50%-200%offshoreareas,theseexcessnutrientsleadtocoastalalgalgrowth.Marinepollutioncausefrequentoccurrenceofredtide,destructionofmangroves,coralreefs,seagrass;alsodecimatedcoastalfishandcausefisherylosses.Wastesolidemissionisincreasingwiththepopulationandlifelevelgrowth.Itisestimatedthattheglobalannualwastegeneratednearly10billiontonseveryyear,ofwhichdevelopedcountriesaccountforalargeproportion.Wastedisposalcapacityisfarlessthanthespeedofwastegenerated.Alotofgarbagearenotbiodegradableordecomposeveryslowly,somoreandmoregarbagepileupintomountains.Somewasteistoxic,inflammable,corrosiveandradioactivespecies,whicharehazardstohumanhealth.PoisonousandharmfulchemicalspollutionwasfirstlyproposedinthebookTheSilentSpring(RachelCarson,1962),whicharousethehumanenvironmentalprotectionconsciousness.Whilemanagementofpoisonousandharmfulchemicalsjusthasbeenstartedrecently,muchlaterthanatmosphericandwaterenvironmentalproblems.Withthedevelopmentofscience,technologyandeconomic,theamountofhazardouswastegenerationisincreasing.Itisestimatedthattheworld'shazardouswasteaccountsforabout10-20%ofindustrialwaste,hazardouswastechemicalindustryisthemostimportantindustrialhazardouswastecomponents.SuchastheU.S.60%ofhazardouswastefromthechemicalindustry;followedbythemetallurgicalindustryaccountsforabout10%,oilandcoalprocessingaccountedfor5%.Recently,developedcountriesgeneratemorehazardouswaste,therefore,transboundarymovementofhazardouswas