Aboard his papal plane as hurricanes pummeled parts of the Americas, the Catholic leader said it was "stupid" to deny climate change. He said history would judge world leaders who did not act on advice from scientists.
Returning from a trip to Colombia, where he urged people there to overcome divisions after the government reached a peace deal with leftist rebels, Pope Francis strongly criticized climate change deniers.
"A phrase from the Old Testament comes to mind: 'man is stupid, a stubborn, blind man'," he told reporters.
Francis said those who doubted climate change should ask scientists about it.
"They speak very clearly; scientists are precise. We can see the effects of climate change and scientists clearly say what path we should follow," he added, referring to the scientific consensus that global warming is caused by human activity such as burning fossil fuels.
He was responding to a question about whether political leaders should be held morally responsible for future effects on the planet, as his papal charter plane flew over some of the areas devastated by recent hurricanes, which continue to affect the US, Mexico and the Caribbean.
The Pope added that everyone, from politicians to each individual, had a moral responsibility to take climate change seriously.
Concern for the planet
Francis is a major supporter of the 2015 Paris climate accord, which aims to cut emissions blamed for global warming.
Ahead of that summit he wrote a major encyclical or papal letter on the state of the environment called "Laudato Si," which backed efforts to stem global warming. Earlier this year, US President Donald Trump withdrew his country from the Paris agreement. The Vatican had urged him to stay in the accord.
Pope Francis also called on Trump to reconsider his decision to end the DACA program (Deferred Action on Childhood Arrivals), introduced by his predecessor Barack Obama, an amnesty for young people, known as "Dreamers," who were brought to the US undocumented as children.
se/rc (dpa, Reuters, AP, AFP)