Lord Carey of Clifton, who was archbishop from 1991 to 2002, was speaking after a NatCen Social Research Survey found the number of people calling themselves Anglican in the UK fell by around 1.7 million from 2012 to 2014.
Proportionally, this was a fall from 21 percent to 17 percent of people in the UK.
Approximately 8.6 million people defined themselves as Anglicans in 2014.
According to The Mail on Sunday, Lord Carey said: "These figures are a call to urgent mission.
"I have no doubt at all that the Archbishops, together with the whole leadership of the Church of England, are doing all they can to reverse this trend."
The former Church of England leader has said previously at a conference in Shrewsbury in 2013 regarding Church of England attendance: "In many parts of Britain churches are struggling, some priests are diffident and lack confidence; a feeling of defeat is around.
"The burden seems heavy and joy in ministry has been replaced by a feeling of heaviness.
"One of the most worrying, most urgent groups we need to invest in is young people.
"We ought to be ashamed of ourselves."