BBC: The Pope's closest adviser on ecology has urged Catholics to join global climate marches planned for Sunday.
In an internal letter to bishops, Cardinal Peter Turkson says people should be "encouraged" to exercise their "ecological citizenship".
The letter says that climate negotiators meeting in Paris need to hear the voice of "God's people".
Activists say the call is evidence of a step-change in the Church's approach to climate change.
Major demonstrations across the world have been...