President Donald Trump's nominee for ambassador to the United Nations has broken with his viewpoint on climate change, saying it "poses real risks".
Kelly Craft told lawmakers at her confirmation hearing she would "be an advocate for all countries to do their part in addressing climate change".
In the past, she had claimed to believe "both sides" of the climate debate.
Mr Trump has previously called climate change a "hoax" and questioned the scientific consensus on the matter.
Earlier this month,
Mr Trump said climate change "goes both ways" and blamed other nations for worsening air and water quality.
In 2017, he pulled the US out of the landmark Paris climate agreement, saying the deal was disadvantageous to US workers.
Mrs Craft who is currently serving as the ambassador to Canada, had offered a similar opinion in 2017, telling CBC she believed "there are scientists on both sides that are accurate".
But she reversed that viewpoint on Wednesday, telling the Senate Foreign Relations Committee that "human behaviour has contributed to the changing climate".
"Let there be no doubt: I take this matter seriously."
She also acknowledged "that fossil fuels have played a part in climate change".