Worried: Pope tells leaders to act on climate
Pope Francis had time for a laugh with nuns in St Peter's Square in the Vatican yesterday.
But earlier he struck a more sombre note this week telling world leaders that climate change was a "challenge of civilisation" they had to tackle while a window of opportunity was still open.
In a video broadcast to the UN Climate Action Summit, Francis called for honesty, responsibility and courage to face what he called "one of the most worrying phenomena of our time".
Leaders had to conjure up the political will to tackle it.
"While the situation is not good and the planet is suffering, the window of opportunity is still open. We are still in time," he said. "Let us not let it close. Let us open it with our determination to ensure a better life for future generations."