In this lesson we are going to discuss the definition of climate change and the its causes
Climate Change- Establishment of a newclimatic state.- Continuous changes inclimatic states such astemperature and precipitationover time.Causes of Climate ChangeNatural Causes1. Variations in the EarthsOrbital Characteristics-Changing of earth’s orbitalcharacteristics within 1000years from elliptical(aphelion) to nearly circular(perihelion) when the earth isnearest to the sun and receivesmaximum solar energy andback to elliptical when theearth is farthest from the sunand receives least solarenergy.2. Variation in theAtmospheric CarbonDioxide-When natural rise intemperature cause carbondioxide held up in Cold Oceanwaters to be released to theatmosphere after oceans havebeen warmed.3. Volcanic Eruptions• When large quantities ofvolcanic ash and dust thrownout of the ground block someof the solar insolation fromreaching the earth’s surfacecausing temperatures on theearth’s surface to drop for ashort period.• When sulphur dioxide givenoff during volcanic eruptionsreacts with water vapourforming a bright layer withinstratosphere reducing theamount of solar radiationreaching the surface byreflecting some of it backwhich also lowerstemperatures on the surface.4. Variation in Solar Output- changes in the amount ofsolar energy given off by thesun whereby at times its lesscausing drop of temperatureon the earth’s surface and atothers it gives off morecausing rise in temperature onthe surface.Human Causes1. Burning of fossil fuels inindustries, transportation,electricity generation e.t.cwhich contributes 65% ofadditional co2 in theatmosphere which is the maingreenhouse gas.2. Burning of vegetation e.g.in shifting cultivation andforest fires which also add co2in the atmosphere.3. Clearing large tracts offorests for agriculture,settlement etc. which reducesthe main deposal system forco2 from the atmosphere byphotosynthesis.4. Industrial developmentswhich add gases like methane,nitrous oxide and thosecontaining chlorine andchlorofluorocarbons whichdamages ozone layer whichfilters a greater percentage ofultra violet radiation given offby the sun which causes theaverage temperatures on theearth to rise.