President Trump briefly stopped by a daylong summit of world leaders meeting to discuss climate change at the United Nations General Assembly (UNGA) in New York before leaving to address a meeting on the persecution of religious minorities and his administration's efforts to support religious freedom.

Earlier Monday morning, White House press secretary Stephanie Grisham raised the possibility that Mr. Trump might find time to appear at the climate change summit. "His schedule is ever changing, but it wouldn't surprise me if he popped by," she said in an appearance on Fox News.

And Mr. Trump did end up dropping by a morning session, where he was seen listening to the climate discussion inside the General Assembly Hall. Seated with new U.S. Ambassador to the United Nations Kelly Craft and Vice President Mike Pence, the president listened intently for about 10 minutes before departing for his religious freedom event.

President Trump, flanked by Vice President Mike Pence, attends the U.N. Climate Action Summit on September 23, 2019, in New York. Getty

U.N. Secretary-General António Guterres, who has been making a push to end new coal plant construction by 2020 to curb greenhouse gas emissions, did not want countries supporting the expansion of coal production to have allotted speaking time at the climate summit, so as a result, the leaders of Australia and Japan will reportedly also not be addressing the summit.

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The global community and environmentalists have grown increasingly alarmed over warming trends that have exceeded scientists' models. For instance, a climate study in January showed the world's oceans are warming significantly faster than previously thought. Since 1970, the ocean has warmed 40% more than previous estimates.

The U.N. noted on its website describing the summit that global emissions "are reaching record levels and show no sign of peaking," and that the last four years were the the hottest recorded." And that change, the U.N. said, is beginning to have a "life-threatening impact" as it brings more air pollution, heatwaves and greater risk to food security.

Guterres has called on world leaders to bring to the climate summit "concrete, realistic plans" that build upon what they had already promised to achieve by 2020, with an eye to "reducing greenhouse gas emissions by 45% over the next decade, and to net zero emissions by 2050."

In order to participate in the climate summit, governments had to commit to further action and an additional cutback in the use of fossil fuels.

Mr. Trump has in the past also chosen not to attend climate-related meetings, declining to appear at annual G-7 climate sessions in France this year and in Quebec in 2018.

Over the course of his presidency, the president has undone many of President Obama's environmental initiatives, withdrawing the U.S. from the Paris climate agreement, rolling back regulations like the Clean Power Plan and most recently ending California's authority to set its own stricter fuel emission standards.

Under the terms of the Paris agreement, the U.S. withdrawal will not be final until November 4, 2020, the day after the U.S. presidential election.

The president has also expressed skepticism about government research that shows carbon emissions are warming the planet and warns of potentially catastrophic consequences if the trend continues.

Recent CBS News polling found most Americans say climate change will be a factor in their vote.

The U.N. summit in New York includes speeches from leaders including New Zealand Prime Minister Jacinda Ardern, India Prime Minister Narendra Modi, German Chancellor Angela Merkel and French President Emmanuel Macon. Topics range from addressing carbon neutrality, ending coal use and energy efficiency.

Guterres told CBS News in a recent interview the summit is imperative because the effects of climate change present a growing "global risk."

"You cannot play tricks with nature. Nature strikes back and we are seeing nature striking back," he said.

Elsewhere, climate activists are taking to the streets to press the seriousness of the world's warming climate. In Washington, D.C., climate protesters have shut down major roadways blocking morning traffic as part of the #ShutdownDC movement to call attention to environmental issues.

The United Nations also recently held its Youth Climate Summit — a gathering of young global climate campaigners who have organized worldwide demonstrations this year.