President-elect Donald Trump's nominee for secretary of state said Wednesday he wants the United States to keep "a seat at the table" regarding global warming, despite Trump's pledge to abandon the Paris climate deal.

At his Senate confirmation hearing on Capitol Hill, former ExxonMobil chief Rex Tillerson also said "the risk of climate change does exist, and the consequences could be serious enough that action should be taken."

Tillerson, who is an engineer, was asked repeatedly about his stance on climate change during the day-long hearing, which continues Thursday.

"I think it's important that the United States maintain its seat at the table on the conversations around how to address threats of climate change, which do require a global response," Tillerson said.

"No one country is going to solve this alone."

However, he later said that climate science is "not conclusive" and said the reason to maintain a seat at the table was "so we can judge the level of commitment of the other 189 or so countries around the table and again adjust our own course accordingly."

It was unclear how much sway Tillerson, if confirmed, might have over Trump's vow to abandon the Paris climate deal, signed by 195 countries in late 2015.

Trump said during his campaign that global warming was a hoax invented by the Chinese, and vowed to ditch US commitments to cut down greenhouse gas emissions.

"The president-elect has invited my views on climate change," Tillerson said.

"I look forward to providing those, if confirmed, to him and policies around how the United States should carry it out in these areas."

Asked about the potential for global warming's fallout to lead to violence or unrest, Tillerson responded: "I don't see it as the imminent national security threat that perhaps others do."

According to David Waskow of the World Resources Institute, Tillerson's words were "encouraging.'

"But he must go further," said Waskow.

"As the country's potential top diplomat, Tillerson should understand that the US needs to be a leader on climate change and honor its international commitments," he added.

"Senators should continue to press Tillerson to ensure the US maintains its key role in tackling this issue."

The Paris climate accord represents the first-ever universal, legally binding global climate deal.

It sets out a plan to limit global warming to well below two degrees Celsius over pre-industrial levels and avoid the worst effects of climate change, including ice cap melting and sea level rise.