Laudato Si' is an encyclical written by Pope Francis and is concerned with the cry of the earth and the cry of the poor.
He talks of a paradigm shift in our attitude toward ecology . It's a movement away from viewing it as something separate from humanity to one that views the earth as our common home and an integral part of the human family.
Pope Francis states that the present environmental crisis is a moral problem. Our response to it includes preferential treatment for the poor as they bear the first and largest burden of environmental problems. It is highly recommended to read the pope's encyclical.