pˌɑːpjʊlˈeɪʃən mˈæɾɚz wʌz lˈɑːntʃt æz ðɪ ˈɑːptɪməm pˌɑːpjʊlˈeɪʃən tɹˈʌst fˈɑːloʊɪŋ ɐ mˈiːɾɪŋ ˌɔn twˈɛnti fˈoːɹ dʒuːlˈaɪ nˈaɪntiːnhˈʌndɹɪd nˈaɪnti wˈʌn baɪ ðə lˈeɪt dˈeɪvɪd wˈɪli ænd ˈʌðɚz kənsˈɜːnd ɐbˌaʊt pˌɑːpjʊlˈeɪʃən nˈʌmbɚz ænd səstˌeɪnəbˈɪlᵻɾi.
Population Matters was launched as the Optimum Population Trust following a meeting on 24 July 1991 by the late David Willey and others concerned about population numbers and sustainability.