世界人口急剧增加(SharpIncreaseinWorldPopulation) Accordingtothefiguresgiveninthebarcharts.ittookfromthebeginningofhumanlifetotheyear1830forthepopulationoftheearthtoreachonebillion. Thatrepresentsatimespanofatleasttwomillionyears.Thentheworldpopulationincreasedrapidly,addinguptotwobillionin1930.Thenextbillionwasaddedby1960,onlythirtyyears.Fromthenontheglobalpopulationwasontherise,amountingto4billionin1975,whichisanotherbillionpeopleinonly15years.Thereareatleasttworeasons,Ithink,forthesharpincreaseinworldpopulation.Inthefirstplace,thebirthrateiscontinuouslyclimbinginmanycountries,especiallyindevelopingcountries.Generallyspeaking,peoplethereholdtheopinionthatchildrendon‘tcostmuchandwhentheygetoldenoughtoworktheywillbringinmoneyandthatwhenparentsareold,theywilltakecareofthem.Secondly,thedeathrateinmostdevelopedcountriesdeclinessteadilybecausepeople‘sstandardsoflivingareraisedandhealthcareimproves. Inmyopinion,thechiefreasonforthepopulationgrowthisnotsomuchariseinbirthratesasafallindeathratesasaresultofimprovementsinmedicalcare.