"Long before it's in the papers"
January 27, 2015


Study: population won’t stabilize this century

Sept. 19, 2014
Courtesy of Science
and World Science staff

A new re­port sug­gests Earth’s popula­t­ion will keep ris­ing through this cen­tu­ry—con­trary to past pro­jec­tions that it would sta­bi­lize, peak­ing around 2050.

The new work, based on a sta­tis­ti­cal anal­y­sis of the most re­cent popula­t­ion pro­jec­tions from the Un­ited Na­t­ions, points to Sub-Saharan Af­ri­ca as the main en­gine be­hind the surpris­ing growth. Pat­rick Ger­land of the U.N.’s popula­t­ion di­vi­sion and col­leagues at sev­er­al uni­vers­i­ties ap­plied what they de­scribed as ad­vanced tech­niques to the lat­est U.N. da­ta to es­ti­mate fu­ture de­mo­graph­ic trends, like fer­til­ity and life ex­pect­an­cy. 

They es­ti­mate an 80 per­cent chance that the world popula­t­ion, now 7.2 bil­lion, will grow to be­tween 9.6 and 12.3 bil­lion by the cen­tu­ry’s end. The main rea­son is an in­crease in the pro­jec­tions for Af­ri­ca; de­mogra­phers had pro­jected that fer­til­ity there  would drop, but the re­search­ers con­clud­ed that lev­els of fer­til­ity through­out the re­gion are per­sist­ently high. 

Fur­ther­more, many Af­ri­can wom­en are still hav­ing larg­er fam­i­lies, with a me­di­an of 4.6 chil­dren, in part due to lack of con­tra­cep­tives, the re­search­ers said. Mor­tal­ity from HIV has been re­duced in Af­ri­ca, too, fur­ther con­tri­but­ing to popula­t­ion growth. Old­er peo­ple will probably make up more of the popula­t­ion as well over time, the in­ves­ti­ga­tors said.

They warned that rap­id popula­t­ion in­crease in high-fer­til­ity coun­tries can cre­ate chal­lenges rang­ing from de­ple­tion of nat­u­ral re­sources to un­em­ploy­ment to so­cial un­rest. The growth could be mod­er­ated, the re­search­ers say, by greater in­vestments in girls’ educa­t­ion and family plan­ning pro­grams that pro­vide con­tra­cep­tives; both fac­tors in­flu­ence fer­til­ity. The re­port is pub­lished in the Sept. 19 is­sue of the jour­nal Sci­ence.

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