(Vatican Radio) Pope Francis has urged the international community to urgently follow up on the path set by the climate deal reached in Paris.

Speaking in St. Peter's Square on Sunday after the recitation of the Angelus prayer, the Pope recalled the just concluded Climate Change Conference (COP21) in Paris which saw the signing of an agreement - he said - "described by many as historic".

The Paris pact aims to curb global warming to less than 2°Celsius by the end of the century; it saw nearly 200 countries taking part in tense negotiations over two weeks to strike the first deal to commit all nations to cut emissions.

"With the hope that special attention for the most vulnerable populations is guaranteed - Pope Francis said - I exhort the whole international community to proceed on the path undertaken in the name of an ever more effective solidarity".

And mentioning the fact that next Tuesday, December 15, the 10th World Trade Organization Ministerial Conference will take place in Nairobi, Pope Francis urged participating nations to that Conference to always take into account the needs of the poor when making decisions, and not to neglect the "legitimate aspirations of less developed nations, of the common good and of the whole human family".

The Pope also remarked on the fact that today sees the opening of Holy Doors in Cathedrals throughout the world so that the Jubilee of Mercy can be lived to the full by all. 

He specifically spoke of the fact that "Doors of Mercy" will be opened in places of poverty, need and marginalization and said he specially wanted to send his greetings to prison inmates across the globe.

Meanwhile before the recitation of the Angelus Pope Francis addressed the pilgrims in the Square saying that true conversion calls for a concrete commitment to justice and solidarity.

Drawing inspiration from the Gospel reading for the third Sunday of Advent in which John the Baptist invites all to convert by sharing with the poor, the Pope said: it is clear some attitudes of those in power have not changed and that a true conversion is needed.

"We must change direction and take the path of justice, solidarity, and sobriety: these are the essential values of a fully human and genuinely Christian life" he said.