During a confirmation hearing on Capitol Hill, Democratic senators challenged president-elect Donald Trump's choice to head the Environmental Protection Agency (EPA) over his ties to the energy industry and his past comments on global warming, which he has called a hoax.

During Wednesday's hearing Scott Pruitt - the attorney general from the state of Oklahoma, who has filed more than a dozen lawsuits against the agency he is slated to lead - modified his position, somewhat.

"Let me say to you: science tells us that the climate is changing, and that human activity in some manner impacts that change," he told senators. "The ability to measure with precision the degree and extent of that impact, and what to do about it, are subject to continuing debate and dialogue, and well it should be."

Pruitt, 48, also chaired the Rule of Law Defense Fund, a group of conservative attorneys general that vehemently opposed a number of EPA regulations, and filed lawsuits to try and roll them back.

Both his opponents and his supporters believe his record indicates he will aggressively carry out Trump's vow to slash EPA regulations in order to boost industry, including US oil and gas drilling and coal mining.

"Why are folks so concerned?... We're concerned that we won't be fine with the environment," said Democratic Senator Tom Carper of Delaware. "You joined in a dozen or more lawsuits... going after the EPA. That's why you have the kind of concern you're witnessing here today."

Protesters disrupt hearing

After the hearings were interrupted by protesters shouting "There is no planet B," Pruitt said he would seek effective environmental rules without hurting development.

"Environmental regulations should not occur in an economic vacuum. We can simultaneously pursue the mutual goals of environmental protection and economic growth," he said. He added that he would seek to give states more authority to regulate their own environmental issues.

His comments come on a day when two highly regarded US agencies, as well as the United Nations, reported that for the third year running global temperatures set a new record, with 2016 being the warmest year ever recorded.

Under questioning, Pruitt also said he would remove himself from ongoing cases against the EPA if required to do so by the EPA's ethics commission.

Environmental groups have launched an aggressive campaign, urging lawmakers to block Pruitt's nomination, saying he is doing the bidding of energy companies and industry groups that have made large financial contributions to his election campaigns.

Asked what would be his guiding philosophy as head of the EPA, Pruitt responded: "I believe that the role of the regulator is to make things regular."

bik/rc (Reuters, AFP, AP)