In his presidential address to kick off the Church of England's General Synod, Most Rev Justin Welby said believers had a part to play in "seizing the best future that lies before us".
"We are in a time when the future offers a wider range of opportunity, or of threat, than we have been used to, culturally, politically and economically," he said.
"There are a thousand ways to explain the Brexit vote, or the election of President Trump, or the strength in the polls in Holland of Geert Wilders or in France of Madame Le Pen and many other leaders in a nationalist, populist, or even fascist tradition of politics.
"Almost certainly there is no simple explanation, almost certainly the impact of globalisation economically, or marginalisation politically and of post-modernity culturally have some role to some extent."
Both Justin Welby and the Archbishop of York notably came out as Remainers before the UK EU referendum last year.
The decision warranted criticism from some that they should've kept their political opinions private, but others said clergy have a duty to share their thoughts on issues they deem to be important.
He described the language of public life as "deeply, savagely divided" and warned it "may become worse".
Archbishop Welby went on to Synod members: "There is before the churches of this land, over the next many years, an extraordinary opportunity to be part of reimagining a new Britain, its practices, values, aspirations and global role.
"In this time of a choice between national hope and opportunity or threat and fear we may play the part to which we are called in reimagining our country and seizing the best future that lies before us."