The World’s Fastest Growing Religion: Comparing Christian and Muslim Expansion in the Modern Era

Abstract

Many religious traditions boast spectacular numerical growth in recent history. Usually, such claims have the rhetorical goal of claiming an expansion so spectacular that it might be presented in “miraculous” terms. This chapter compares the changing numbers of followers of the Christian and Muslim faiths worldwide since 1900 and the reasons underlying those changes. Both Christianity and Islam expanded rapidly through a combination of demographic change and successful evangelism. In both cases, demography is the more significant factor. For Christians, almost all growth occurred outside the territories of Europe and North America that had long represented its traditional heartlands. Demography accounted for a fundamental shift in the faith’s center of gravity, towards new lands on Africa, Asia and Latin America. Despite some growth in Africa, Islamic expansion mainly occurred in the territories where it is concentrated, so that this faith did not experience the geographical and cultural shift of emphasis associated with Christians. The slow rate of population growth in Europe means that Islamic numbers worldwide have grown more sharply than Christian. Differences in the type of religious expansion – Muslims in traditional areas of strength, Christians in newer areas – means that Christianity has had to confront more far-reaching questions of cultural assimilation and acculturation than Muslims. In both cases, traditional forms of belief and practice have increasingly been challenged and overwhelmed by new and more globalized forms of faith. Among Christians and Muslims, these new forms of faith claim a special kind of authenticity and pseudo-antiquity, but nevertheless owe much of their success to strictly modern forms of communication and technology. There are parallels between the groups and individuals leading evangelism and expansion among the two religions, comparing new Christian prophets with charismatic leaders of Sufi Muslim sects.