the rapid increase in numbers of a particular species, especially in the world's human population since the end of World War II, attributed to an accelerating birthrate, a decrease in infant mortality, and an increase in life expectancy.
Origin of population explosion
An Americanism dating back to 1950–55
Dictionary.com Unabridged Based on the Random House Unabridged Dictionary, © Random House, Inc. 2019
a rapid increase in the size of a population caused by such factors as a sudden decline in infant mortality or an increase in life expectancy
Collins English Dictionary - Complete & Unabridged 2012 Digital Edition © William Collins Sons & Co. Ltd. 1979, 1986 © HarperCollins Publishers 1998, 2000, 2003, 2005, 2006, 2007, 2009, 2012