ROME — Pope Francis sent a video message to the U.N. Climate Action Summit that opens in New York on Monday, throwing his moral support behind the three-day meeting.

In his message, the pope thanked the U.N. Secretary-General for convening the summit, whose theme is “Climate Change and Sustainability,” for drawing the attention of the entire international community “to one of the most serious and worrying phenomena of our time: climate change.”

The pontiff also lamented the scant progress made to rein in global warming four years after the 2015 Paris Climate Agreement.

The climate accord made the international community “aware of the urgency and need for a collective response” to climate change, Francis claimed, yet “four years after that historic Agreement, we can see that the commitments made by States are still very ‘weak,’ and are far from achieving the objectives set.”

The pope went on to challenge leaders to respond seriously to the climate crisis, which he has called a global “emergency.”

It is necessary to ask “whether there is a real political will to allocate greater human, financial and technological resources to mitigate the negative effects of climate change and to help the poorest and most vulnerable populations, who suffer the most,” he said.

Earlier this month, in fact, the pope called for “drastic measures” to combat global warming.

“Now is the time to abandon our dependence on fossil fuels and move, quickly and decisively, towards forms of clean energy and a sustainable and circular economy. Let us also learn to listen to indigenous peoples, whose age-old wisdom can teach us how to live in a better relationship with the environment,” the pope said.

In his video-message Monday, Francis repeated his belief that there is no time to waste in addressing the climate change crisis.

“While the situation is not good and the planet is suffering, the window of opportunity is still open,” he warned. “We are still in time. Let us not let it close.”

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