WASHINGTON (Reuters) - President-elect Donald Trump’s choice to lead the U.S. Environmental Protection Agency expressed doubt about the science behind global climate change during a contentious Senate confirmation hearing on Wednesday, but added he would be obliged for now to uphold the EPA’s finding carbon dioxide poses a public danger. Oklahoma Attorney General Scott Pruitt, 48, sued the agency he intends to run more than a dozen times on behalf of his state. This earned him strong support from petroleum companies and convinced both his opponents and supporters that he would aggressively carry out Trump’s campaign vows to slash EPA regulation to boost drilling and mining. “Science tells us that the climate is changing, and that human activity, in some manner, impacts that change,” Pruitt said during the hearing in front of the Environment and Public Works Committee. “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.” Responding to a question from Democratic Senator Ed Markey of Massachusetts, Pruitt said he would be obliged as administrator to initially abide by the EPA finding that carbon dioxide and other gases scientists believe contribute to climate change pose a risk to the public. That is a premise for many of the regulations limiting carbon emissions imposed during President Barack Obama’s tenure. “There’s nothing that I know of that would cause a review at this point,” he said. Trump has called climate change a hoax and has promised to refocus the EPA on protecting air and water quality, while scrapping many of Obama’s initiatives to curb carbon dioxide emissions. That stance has triggered an international diplomatic backlash and cast a cloud of doubt over the future of a global pact to fight global warming, signed in Paris last year by nearly 200 countries. U.S. government agencies said on Wednesday that world temperatures in 2016 hit a record high for the third year in a row. “Why are folks so concerned?... We’re concerned that we won’t be fine with the environment,” said Democratic Senator Tom Carper of Delaware during the hearing. “That’s why you have the kind of concern you’re witnessing here today.” An overwhelming majority of scientists say the burning of oil, gas and coal is a driver of global climate change, causing sea level rise and more frequent violent storms. In prepared remarks that were interrupted by protesters shouting “There is no planet B”, Pruitt said he would seek to ensure rules imposed by the EPA were effective, but without hurting development. He added that he would seek to give states more authority to regulate their own environmental issues. “Environmental regulations should not occur in an economic vacuum. We can simultaneously pursue the mutual goals of environmental protection and economic growth,” he said.  For weeks before the hearing, environmental groups campaigned to urge lawmakers to block Pruitt’s nomination, saying his litigation as Oklahoma attorney general may have been influenced by energy companies and industry groups that contributed to his election campaigns. Pruitt said during the hearing that he would recuse himself from any ongoing cases against the EPA that he is involved in, if the EPA’s ethics commission required him to do so. Among these cases is a multi-state effort to overturn the Clean Power Plan requiring states to cut carbon emissions, a centerpiece of Obama’s initiatives to counter climate change. During the hearing, Democratic Senator Jeff Merkley of Oregon showed a blown-up image of a letter Pruitt sent to the current EPA administrator several years ago opposing regulations limiting emissions from the energy sector. Merkley said it had been written by Oklahoma company Devon Energy (DVN.N). Pruitt responded by saying the letter was not sent on behalf of any one company but on behalf of an entire industry that is important to the state’s economy. New Jersey Democratic Senator Corey Booker later asked Pruitt if he had sent similar letters of behalf of Oklahoma citizens affected by pollution, citing statistics showing the major oil and gas producing state has among the highest asthma rates in the country. “Did you even file one lawsuit on behalf of those kids?” Booker later quipped: “There’s a pattern of you being on side of polluters, even when it restricts state rights you claim to promote.” Republicans on the committee focused their questions on how Pruitt will work to prevent pollution from causing serious public health problems like the lead contamination crisis affecting Flint, Michigan, and criticized the Obama administration’s climate regulations. Lawmakers from Midwestern states also asked about his views on biofuels, an important market for corn growers. Pruitt said he would support the U.S. renewable fuels standard, which requires biofuels like ethanol to be blended in gasoline, but said the program needed some tweaks. 