Limits-to-Growth-and-Human-Carrying-Capacity-Vinlove增长的极限承载力与人-vinlove-教学课件

LimitstoGrowthandHumanCarryingCapacity1EnduringUnderstanding:Waterandsoilarevaluableresources,whichmustbeusedmorecarefullyasthehumanpopulationgrows.2.Muchofthecurrentagriculturalpracticesresultinsoildegradationandwaterpollution.Thusourfoodsupplyisunsustainable.3.Nonrenewableenergyresourceswillbeconsumedatsomepoint,makingthedevelopmentofrenewableresourcesveryimportant.4.Reductioninwastesthroughrecycling,reuseandremanufacturingwillbecomemoreimportantasthepopulationincreases.5.Humanpopulationsimportmaterials,makingitdifficulttoestimatethecarryingcapacityofanarea.2K:CarryingCapacityThenumberofindividualsagivenareaoflandorwatercansustainablysupportovertime.Thecarryingcapacityforhumansistheinverseoftheecologicalfootprint.

3FootprintvsCarryingCapacityTheCarryingCapacityforHumansistheinverseoftheecologicalfootprint.Reviewthedefinitionofecologicalfootprinttocheckthis!4LimitingFactorsLimitingfactorsarefactorsorresourcesthatlimitthesizeofapopulation.Thepopulationcannotgrowlargerbecauseoftoomuchortoolittleofafactor.5Example10rabbitsmayliveinahabitatthathasenoughwater,coverandspacetosupport20rabbits.ifthereisonlyenoughfoodfortenrabbits,thepopulationwillnotgrowanylargerthan10.Foodisthelimitingfactor6LimitingfactorssetalimitonpopulationgrowthFood,water,nestingsites,predation7KversusrstrategistsKstrategiststendtohaveafewoffspringthatreceivealotofparentalcare. Examples:birds,elephantsandhumansrStrategiststendtohavemanyoffspringwithnoparentalcare. Ex:spiders,fish8CompareKtorstrategists9Sigmoidcurvephases1.Lagphase2.ExponentialGrowth(RapidGrowth)3.Stablephase10Amorerealisticpopulationgrowthcurve11Manypopulationsovershootthecarryingcapacity12

HumanPopulationGrowth13Whatdoyouthink?“Ifwefailtobringpopulationgrowthandoverconsumptionundercontrol,thenwewillinhabitaplanetwherelifebecomesincreasinglyuntenable.” -PaulEhrlichAuthorofThePopulationBomb14FoodAnestimated1in6peoplesufferfromhungerandmalnutritionwhileattemptstogrowfoodaredamagingswathesofproductiveland.-BBC15WaterBy2025,two-thirdsoftheworld'speoplearelikelytobelivinginareasofacutewaterstress.-BBC16EnergyOilproductioncouldpeakandsupplieshavestarttodecline.17ClimateChangePossiblytheworld’sgreatestenvironmentalchallenge.18PollutionAnestimatedoneinfourpeopleworldwideareexposedtounhealthyconcentrationsofairpollutants.-BBC19LossofBiodiversityThesixthmassextinctioniscausedbyONEspecies:Man!20LocalCarryingCapacityLifestylesaffectresourceuseandrequirementsExamples?2122LocalCarryingCapacityTechnologicaldevelopmentscausechangesinresourcerequirementsandconsumptionExamples?2324LocalcarryingcapacityishardtopredictforhumanpopulationsTherangeofresourcesusedbyhumansismuchgreaterthananyotherspecies.Whenoneresourcebecomeslimiting,humanssubstituteanother.Suggestexamples..25DifficultiesinestimatinghumancarryingcapacityHumanpopulationsregularlyimportresourcesfromoutsideCitiescangrowbeyondtheboundariessetbytheirlocalresourcesImportingresourcesincreaseslocalcarryingcapacity26LocalCarryingCapacityWhatisthecarryingcapacityofacitysuchasTokyo?Canitbeestimated?27WhatisthevalueofKforthewholehumanpopulation?Humancarryingcapacityisdeterminedby:1)therateofenergyandmaterialconsumption2)thelevelofpollution3)theextentofhumaninterferenceingloballife-supportsystems…28InfluencesinCarryingCapacityEconomistsarguethattechnologycanhelphumancarryingcapacitytoexpand.UseenergymoreefficientlyUsematerialsmoreefficientlyLowerresourceuseandpollution29Reuse,RecyclingandremanufacturingReuse,recyclingandremanufacturingcanlowerhumanimpactontheEarthTheycanalsoincreasehumancarryingcapacity30Reuse–Don’tthrowitaway!31Reuse–Useitagain!32Recycle:Turnitbackintothesameitem!33Remanufacture:Convertitintosomethingnew34Ecologistswarn…..Theworldpopulationisforecasttoincreasefrom7billionto9.5billionpeoplewithinthenext30years.Efficiencywillneedtobeincreasedbyafactorof4to10toremainwithinglobalcarryingcapacity.35Doeshumanityhaveacarryingcapacityand,ifso,whatisit?Thehumanpopulationgrowthcurveiscurrentlyfollowinganexponentialcurveora"J-shape”.

Resourcelimitationsand/orhabitatdegradationwillforcethehumanpopulationcurvestoap