Under a "high-growth" scenario Muslims would number 75.6 million on the continent in three decades.
Europe's Muslim population will likely double by 2050 even if European countries stop accepting refugees, according to a new study by the Pew Research Center.
Pew acknowledges that "Europe's Muslim population is diverse" with varying degrees of religious commitment and belief, but says such factors are outside the scope of its report.
While Muslims made up 6 percent of Germany's population past year, their proportion would go up to 20 percent by 2050.
Under the "medium" scenario, Britain - the top destination for non-refugee Muslims migration - would pass out France while under the "high" scenario the mantle would pass to Germany, which has received over 1.5 million refugees in the past two years.
A new report by U.S. nonpartisan think tank Pew Research Center projects a dramatic rise in the Muslim population in many Western European countries over the next several decades, from about 5% of the continent now to up to 14% by 2050. Under these conditions, Muslims could comprise 11.2 percent (59 million) of Europe's population in 2050.
Attempting to soothe readers, Pew stresses that the refugee flows of recent years are extraordinarily high compared with the historical average, and that these have begun to decline amid changes in the migration policy of many European countries.
The countries covered in the study included the 28 European Union members, plus Norway and Switzerland.
Europe's Muslim Population May Double by 2050 Even Without Refugees, Study Says
Europe received more than one million migrants and refugees in 2015, according to figures from the UN's refugee agency.
The research centre sets out three different projections for the coming decades, according to varying estimates of future migration levels. Under the "medium" scenario, it would rise to 517 million people, while in the "high" migration scenario would take it to 539 million. Europe's non-Muslim population is estimated to decline.
A third, "high" migration scenario, in which the heavy influx of predominantly Muslim migrants recorded between 2014 and 2016 continues indefinitely, paints a far more pessimistic picture.
PARIS: Muslims could make up over 11 percent of Europe's population in the coming decades, compared with just under 5 percent now, if legal migration levels are maintained, a report by a US-based think tank said on Thursday. The number of Muslim migrants arriving in Europe surged after 2014 to nearly half a million annually, largely due to people fleeing conflicts in Syria, Iraq and Afghanistan, it said.
This is because the United Kingdom is a popular destination for Muslim migrants but has accepted relatively few refugees compared to other European countries such as Germany.
Also, if high migration continues until 2050, Britain's Muslim share will grow to 17.2 percent, Finland's to 15 percent and Norway's to 17 percent.
These projections make interesting reading given another recent Pew Research Center survey, which found that refugees from Iraq and Syria were perceived as a far greater threat in some countries where there were relatively few of them (Greece, Italy and Poland for example), than in countries such as Germany and Sweden, which had attracted large numbers.