GlobalWarmingClimateChangeextremeweatherevents===Wet===extremeweatherevents===Dry===extremeweatherevents===Hot===AverageWeatherConditionsInitialCausesOfTemperatureChangesSolarvariationscausingchangesinsolarradiationenergyreachingtheEarthhavebeenthecauseofpastclimatechanges.Theeffectofchangesinsolarforcinginrecentdecadesisuncertain,butsmall,withsomestudiesshowingaslightcoolingeffect,whileothersstudiessuggestaslightwarmingeffect.ShiptracksovertheAtlanticOceanontheeastcoastoftheUnitedStates.Theclimaticimpactsfromparticulateforcingcouldhavealargeeffectonclimatethroughtheindirecteffect.Globaldimming,agradualreductionintheamountofglobaldirectirradianceattheEarth'ssurface,wasobservedfrom1961untilatleast1990.Themaincauseofthisdimmingisparticulatesproducedbyvolcanoesandhumanmadepollutants,whichexertsacoolingeffectbyincreasingthereflectionofincomingsunlight.Radiativeforcingduetoparticulatesistemporallylimitedduetowetdepositionwhichcausesthemtohaveanatmosphericlifetimeofoneweek.Carbondioxidehasalifetimeofacenturyormore,andassuch,changesinparticulateconcentrationswillonlydelayclimatechangesduetocarbondioxide.Greenhouseeffectschematicshowingenergyflowsbetweenspace,theatmosphere,andearth'ssurface.Energyexchangesareexpressedinwattspersquaremeter(W/m2).TheGreenhousegasesThisfigureshowsclimatemodelpredictionsforglobalwarmingundertheSRESA2emissionsscenariorelativetoglobalaveragetemperaturesin2000.GlobalWarmingGlobalWarmingGlobalWarmingExcerpt18’30”~24’45”PositiveAndNegativeEffectsOfGlobalWarmingFreeAirCO2EnrichmentOceanexpandsea-levelriseTheretreatofAletschGlacierintheSwissAlps(situationin1979,1991and2002),duetoglobalwarming.Methane:AMenaceSurfacesSpeciesextinctionCoralScientificAmericanJune2010ScientificAmericanNovember2009