Republican presidential nominee Donald Trump Donald John TrumpBubba Wallace to be driver of Michael Jordan, Denny Hamlin NASCAR team Graham: GOP will confirm Trump's Supreme Court nominee before the election Southwest Airlines, unions call for six-month extension of government aid MORE said there is still a lot about climate change that needs to be investigated.

Responding to a questionnaire from Scientific American and numerous scientific organizations, Trump repeated his doubt about climate change, putting quotes around the term and saying that the country’s limited resources should probably go somewhere other than fighting it.

ADVERTISEMENT

“There is still much that needs to be investigated in the field of ‘climate change,’” he wrote.

He then wrote that the country’s limited money should “perhaps” go to other causes, like ensuring clean water, fighting malaria, feeding a growing population or even reducing the need for fossil fuels.

“Perhaps we should be focused on developing energy sources and power production that alleviates the need for dependence on fossil fuels,” he said. “We must decide on how best to proceed so that we can make lives better, safer and more prosperous.”

Later, on the topic of scientific integrity, Trump wrote that “science is science and facts are facts.” He promised “total transparency and accountability without political bias” in his administration’s scientific endeavors.

Democrat Hillary Clinton Hillary Diane Rodham ClintonJoe Biden looks to expand election battleground into Trump country Biden leads Trump by 12 points among Catholic voters: poll The Hill's Campaign Report: Biden goes on offense MORE, by contrast, said the science is “crystal clear” that climate change “is an urgent threat and a defining challenge of our time and its impacts are already being felt at home and around the world.”

She repeated her previous campaign pledges to set a goal of getting half the country’s electricity from clean sources, install 500 million solar panels and cut energy waste and oil use by a third each.

Green Party nominee Jill Stein called climate change the “greatest existential threat that humanity has ever faced” and reiterated her pledges, including transitioning to 100 percent renewable energy by 2030.

Libertarian nominee Gary Johnson Gary Earl JohnsonWhat the numbers say about Trump's chances at reelection Presidential race tightens in Minnesota as Trump plows resources into state The Hill's Campaign Report: Biden condemns violence, blames Trump for fomenting it l Bitter Mass. primaries reach the end l Super PAC spending set to explode MORE did not respond to the questionnaire, Scientific American said.