Africa's beauty, which inspired people to praise God, was at risk, the Pope said. Photo: Reuters
By BBC News
Pope Francis says that the illegal trade in ivory and diamonds fuels conflict and could destroy Africa's environment.
Speaking on the second day of his visit to Kenya the Pope linked trafficking to "organised crime and terrorism". He also warned world leaders not to let special interests prevail over common good in next week's climate talks.
The Pope earlier addressed a Mass in Nairobi where he urged people to create a "just" and "inclusive" society.
He turned his attention to environmental issues when he was talking at the headquarters of the UN Environment Programme in the Kenyan capital.
In his fourth speech of the day, the pontiff said that "Africa offers the world a beauty and natural richness" which inspired people to praise God.
But that was being threatened, by "human selfishness of every type" as people's poverty was being exploited to push them into the illegal trade of diamonds, rare metals, timber and ivory, he said.
"We cannot be silent about forms of illegal trafficking which arise in situations of poverty and in turn lead to greater poverty and exclusion," Pope Francis said.
The pontiff, in Kenya on the first stop on a three-nation tour of Africa, also had a hard hitting message ahead of next week's climate talks in Paris, saying it would be "catastrophic" if the needs of poorer nations were ignored.
Repeating a warning from earlier this year he said: "The climate is a common good, belonging to all and meant for all."
Earlier on Thursday the Pope celebrated Mass at a university campus with tens of thousands of people who had waited in the rain from the early hours of Thursday morning.
Pope Francis made a plea for traditional values and urged Kenyans to work for peace and reconciliation on his first trip as pontiff to Africa, amid a rise in militant violence.
Christian population is 517 million (63% of total) Protestants make up more than half the number Catholics make up about a third Muslim population is 248 million (about 30% of total) 1.1 billion Christians expected by 2050 670 million Muslims expected by 2050
Before the Mass, Pope Francis met religious leaders from other faiths and other Christian denominations, who he said should be "prophets of peace" in a violent and hate-driven world.
Soldiers patrol during a mass celebrated by Pope Francis on the campus of the University of Nairobi,
Referring to attacks carried out by the militant Islamist group al-Shabab in Kenya, he said that God's name "must never be used to justify hatred and violence".
The BBC's Anne Soy said that security was very tight for the Mass, but the pontiff played down security fears, joking that he was "more worried about the mosquitoes".
Pope Francis's five-day visit to Africa will also see him go to Uganda and Central African Republic, which has been hit by Christian-Muslim conflict.