Pope Francis blasted global warming skeptics on Thursday as having "perverse attitudes."

The pontiff, during remarks made to negotiators at climate talks in Germany, called climate change "one of the most worrisome phenomena that humanity is facing." He added efforts to combat climate change are held back by those who deny the science behind it, are indifferent or resigned to it, or think it can be solved by technical solutions.

"We must avoid falling into these four perverse attitudes, which certainly don't help honest research and sincere, productive dialogue," he said.

He urged negotiators at the Bonn meeting to take action free of special interests and political or economic pressures, and to instead engage in an honest dialogue about the future of the planet.

Negotiators at the Bonn meeting are working to implement the 2015 Paris Climate Accord aimed at capping global emissions.

The pope did not cite any countries by name, but President Trump previously announced the United States is withdrawing from the Paris accord.

In 2016, Francis said global warming is "mainly" due to human activity and he called for fossil fuels to be progressively phased out without delay.

The Associated Press contributed to this report.