All Catholics must accept Catholic social teaching with religious submission of mind and will; Laudato Si' summarises Catholic social teaching where environmental and related issues are concerned; Laudato Si' applies Catholic social teaching to the current state of the environment as perceived by Pope Francis; The Pope's description of the state of the environment is open to debate; On climate change the Pope opts for and heavily promotes the "consensus" account of the science without referenced justification and does not refer to any other view; The Catholic Church lacks the competence to resolve continuing scientific debates; The debate over anthropogenic global warming is far from complete; Laudato Si', Pope Francis' Encyclical Letter On the Care of Our Common Home, repeatedly calls for a "forthright and honest debate" (nn. 16, 61, 135, 138, 188); The present author takes no "side" in the debate about climate change and wants the debate to continue, but in a context which provides for a much fairer hearing to be given to all sides to that debate; This book as a part of the Living Ethics Series is intended as a contribution to that "forthright and honest debate" on environmental issues generally for which the Pope calls.