A hallmark of President-elect Donald Trump's political positions has been that they often flow with popular sentiment. There's the Iraq War, which he initially supported but then turned against as public opinion changed. There's immigration policy restructuring, which he (along with the Republican establishment) championed shortly after the 2012 election. And there's climate change.

Over the past 10 years, the question of mankind's role in the warming climate has become a deeply polarized one in U.S. politics. An October survey from Pew Research found that only 15 percent of conservative Republicans think climate change is a function of human activity, compared with 79 percent of liberal Democrats. That wasn't always the case. Sen. John McCain's (R-Ariz.) 2008 presidential campaign included a specific articulation of his support for addressing climate change. That same year, Newt Gingrich and Rep. Nancy Pelosi (D-Calif.) sat together in a PSA addressing the need to address climate change.

This year, Trump has been a staunch opponent of the need to address climate change, arguing for an increase in coal use and suggesting that he would withdraw the United States from a landmark agreement meant to curb greenhouse gas emissions.

Until, that is, he sat down Tuesday with the New York Times.

Trump's interest in the subject of climate change appears to have been awakened by his effort to develop a golf course in Scotland. As we outlined in September, a proposal to build an offshore wind farm near the location of the course prompted a years-long push by Trump to block their construction. (The issue still resonates with him; he reportedly told British politicians this month to keep fighting such plans.) Interviewed by a Scottish newspaper in 2008, Trump suggested that fog which often blanketed the area by the golf course would not be a problem for much longer. Perhaps, he said, “global warming — which I don't necessarily believe in, at least the human part — is going to take care of that.”

That position almost certainly related to his opposition to the wind farm, which itself was proposed in part to make the local energy infrastructure cleaner. (A main source of atmospheric carbon dioxide, a prolific greenhouse gas, is the burning of coal and oil for electricity production.) Trump mostly focused his ire on the proposal itself, though, frequently tweeting disparaging comments about wind turbines. He mostly wasn't tweeting about climate change itself.

At the end of 2009, in fact, he, along with his children and a number of other business leaders, was a signatory to a letter that called for Congress and President Obama to take urgent action to “invest in a clean energy economy” — that is, one not dependent on fossil fuels — that would “spur economic growth, create new energy jobs, and increase our energy security all while reducing the harmful emissions that are putting our planet at risk.” It's not clear what the genesis for this letter was, but it appears to have been an organized effort by members of the business community.

Only a few months later, though, when Trump was asked about climate change on Fox News, he told host Neil Cavuto that the cold weather (it was January) was evidence that there was no climate change. What's more, he argued, efforts to curtail climate change are “putting this country at a competitive disadvantage.” Again, this was a few months after he argued that addressing climate change would benefit the country economically.

Over the next few years, which overlapped with Trump's 2011 flirtation with seeking the Republican nomination for the presidency, he continued to tweet disparagement about the nature of climate change, even suggesting that the idea was created by China to deliberately put the United States at a disadvantage. (In a debate, he denied saying this.)

Once the 2016 campaign rolled around, Trump's opposition to addressing climate change was fervent. He seized on the idea that regulations advanced by the Obama administration were gutting the coal industry. (The number of jobs in coal began plummeting in the 1980s for a variety of reasons, including regulations aimed at curtailing particulate and greenhouse gas emissions.) Trump seized on the politically powerful subject of climate change, regularly disparaging Obama's efforts to address the issue and suggesting that the real threat of climate change was the detonation of nuclear weapons.

“I am not a great believer in man-made climate change. I’m not a great believer,” he told The Washington Post during a sit-down during the primaries. “There is certainly a change in weather that goes — if you look, they had global cooling in the 1920s and now they have global warming, although now they don’t know if they have global warming." (There wasn't widespread scientific belief in “global cooling” in the 1920s.)

“Perhaps there’s a minor effect, but I’m not a big believer in man-made climate change,” Trump said at the time. Shortly before the general election, his campaign manager confirmed Trump's position: Warming is happening, but it's not mankind's fault.

Scientists disagree.

There was an exception to his anti-climate fervor while he was campaigning. Asked by a woman in Iowa whose husband worked at a wind turbine manufacturing company, Trump said that he supported wind turbines and that he even supported subsidizing turbine production.

Here's Trump in 2012.

That brings us back to his comments Tuesday. Speaking to reporters from his hometown paper, Trump suggested that perhaps mankind did play a role, after all. It's possible that this was in part because of his audience. When he was speaking with The Post in March, he said that his position “hurts me with this room, and I know it’s probably a killer with this room.” It's clear that his enthusiastic bashing of climate change at rallies was itself in part a function of playing to the audience: People showing up to hear him speak in West Virginia didn't want to hear a nuanced position on climate change.

So, for those keeping score, Trump has:

  1. Denied that climate change is happening and called it a hoax.
  2. Suggested that the world is actually warming, but that humans aren't involved.
  3. Suggested that the world is warming and that humans had a “minor” effect.
  4. Suggested that the world is warming and that there is some “connectivity” to human behavior.
  5. Called for the adoption of policies to curtail human-caused climate change, providing a boon to the economy.

That's all within the past 10 years. Where Trump actually stands once he has to make a decision as president is anyone's guess. But, as always, pay attention to public opinion and the opinions of the people around him.