On Thursday, Pope Francis will deliver a papal encyclical on ethical issues and environment. The official guide states that humanity is 'slapping nature in the face'.

The Pope is expecting the paper to have a great impact on UN conference to be held in Paris in December. The nations can pledge to cut emissions. It is said the encyclical is the highest level of document that the pope can issue.

Papal encyclical is a letter from the Pope to bishops sent with an aim to help guide church teachings for the world's Catholics and is considered as an important instruction for the community. Many said that there is no problem if the Pope has to remind that humanity is a responsible steward of earth.

Already, the Pope has announced that pollution is not good for earth and is a sin. There are many who are not linking the interference of the Pope into politics and there are chances, some will even question his science as well.

In April, the Heartland Institute, a conservative think-tank in the US, carried out a conference in which it challenged the Pope's views on climate change. "We believe Pope Francis is making a mistake if he puts his moral authority behind UN modelling which is flawed and incorrect", said Jim Lakely, a spokesman for Heartland.

The paper's title, Laudato Si, has been taken from a prayer by St Francis having a line 'our sister Mother Earth who feeds us'.