Islam is the only religion growing faster than the world's population, and it will be the largest in the world by 2070, research has found.
US-based Pew Research Centre analysed demographic change among the world's major religions and found that the world's population of Muslims will grow by 73 per cent between 2010 and 2050, compared to 35 per cent for Christians, the next fastest-growing faith.
The world's population will grow by 37 per cent over the same period. If those rates of growth continue past 2050, Muslims will outnumber Christians by 2070, the report found.
It also says that Muslims will make up 10 per cent of Europe's population.
In 2010 there were 1.6bn Muslims in the world, and 2.17bn Christians. By 2050, there will be 2.76bn Muslims and 2.92bn Christians - and if both religions continue at that rate of growth, Islam will have a larger number of followers than Christianity by 2070.
Atheists, agnostics and non-religious people will decline from 16.4 per cent of the world's population to 13.2 per cent by 2050, the report added, despite growing in Europe and North America.
The changes are partly due to the various fertility rates each religion has. Muslims have the highest, at 3.1 children per woman, followed by Christians, at 2.7.
Islam also has a much younger follower-base than other religions, meaning believers still have childbearing years ahead. 34 per cent are aged under 15, compared to a global average of 27 per cent.
Christianity is also likely to suffer as more converts leave to become non-religious or to join other faiths, the report predicted.
Around 40 million people are projected to switch into Christianity globally, while 106 million are predicted to leave.
The report also summarises findings from a survey last year into European attitudes towards Muslims.
"Majorities in Hungary, Italy, Poland and Greece say they view Muslims unfavorably, while negative attitudes toward Muslims are much less common in France, Germany, the United Kingdom and elsewhere in Northern and Western Europe.
"People who place themselves on the Right side of the ideological scale are much more likely than those on the Left to see Muslims negatively," it said.