Jeb Bush rejected on Thursday what he called an arrogant view that anyone who questions how much climate change is a result of human activity is considered "Neanderthal."
Bush, answering questions from reporters after an event in Salem, New Hampshire, defended remarks he made a day earlier in which he said scientific research does not clearly show how much of climate change is caused by humans and how much is from natural causes.
The United Nations panel of climate scientists, which is composed of thousands of the world's leading climate change experts, says it is at least 95 percent probable that most of the warming since 1950 is caused by man-made greenhouse gases.
"My views are that the idea that science has established what percentage of climate change is human-derived and what is natural, it's not finished. It's not determined," said Bush, who is exploring a 2016 Republican presidential run.
Bush seemed to be taking issue with President Barack Obama, who has regularly criticized politicians who question climate change. Obama repeated the criticism on Wednesday in declaring climate change a national security priority.
"There are folks who will equivocate. They'll say, 'You know, I'm not a scientist.' Well, I'm not either. But the best scientists in the world know that climate change is happening," Obama said.
Bush said there is no doubt that climate change is real but said there should be room for differing views on why it is occurring.
"I find this a lot in these debates when people say, 'Well everybody knows, the science is clear.' Well, it's not so clear and there is diverse views on these things particularly as it relates to the influence of man on this subject," he said.
"Why do we have to have a debate where people who have doubts about this are considered Neanderthals? That's the arrogance," Bush said.
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