Don Melvin writes that, excluding Russia, Europe's Muslim population will double by 2020. He also says that almost 85% of Europe's total population growth in 2005 was due to immigration in general.[19][21] Omer Taspinar predicts that the Muslim population of Europe will nearly double by 2015, while the non-Muslim will shrink by 3.5%, due to the higher Muslim birth rate.[22] Esther Pan predicts that, by 2050, one in five Europeans are likely to be Muslim.[22][23]
Professor Philip Jenkins of Penn State University estimates that by 2100, Muslims will compose about 25% of Europe's population. But Jenkins admits this figure does not take account of the large birthrates amongst Europe's immigrant Christians.[24]
Other analysts are skeptical about the given forecast and the accuracy of the claimed Muslim population growth, since there has been a sharp decrease in Muslim fertility rates.[25] A Pew Forum study, published in January 2011, forecast an increase of Muslims in European population from 6% in 2010 to 8% in 2030.[26] PEW also found that Muslim fertility rate in Europe would drop from 2.2 in 2010 to 2.0 in 2030. On the other hand, the non-Muslim fertility rate in Europe would increase from 1.5 in 2010 to 1.6 in 2030.[27]
