In his first "Urbi et Orbi" (to the city and the world) message, Francis also called for peace between Israelis and Palestinians, an end to the civil war in Syria, and political solutions to conflicts in several African countries.
The former Cardinal Jorge Bergoglio of Argentina also condemned the "iniquitous exploitation of natural resources" and urged everyone to be "guardians" of creation.
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Warmer with a mild, muggy night ahead
The headteacher of Saffie Rose Roussos's primary school has paid tribute to the little girl who was "beautiful in every sense of the word".
Ten people have died on the mountain so far this climbing season - four more than mountaineering officials expect in a typical year.