Fifteen cyclists including two parish priests, students and pensioners will set off on Phase 1 of the London-Paris Pilgrimage on Saturday morning from Westminster Cathedral.
The group from the Westminster Justice and Peace Commission will follow the Avenue Verte to the Green Way route linking London and Paris, passing through built-up South London, then following scenic cycle ways, up over the High Weald, then downhill to the South Coast to Newhaven, a total of 100 miles for Phase 1.
The second Phase will start at Dieppe in November and follow the Avenue Verte for 130 miles to Paris, to join in meetings, lobbies and rallies for a world decision to save our planet from further global warming.
"I send my best wishes to participants in the first phase of the Diocese of Westminster Justice and Peace Cycle from London to Paris," said Cardinal Vincent Nichols.
"The witness of this event, in both teaching and action, highlights the importance of the forthcoming climate conference in the care of our common home. Travel safely and may God bless you all," added the Archbishop of Westminster.
The international climate conference will be held at Le Bourget from November 30 to December 11, 2015.
The conference objective is to achieve a legally binding and universal agreement on climate, from all the nations of the world.
The UK government's latest climate change assessment identifies extremely wet winters as a result of global warming could become up to five times more likely over the next 100 years, leading to increased flooding.
The government estimates that annual damages from flooding could increase to £12bn by the 2080s, an increase of about 10 times compared with current estimates.