Donald Trump doesn't believe global warming is a real threat to the USA.
He tweeted his opinions on the matter in 2012 and 2014, although later denied his tweets, when challenged by Hillary Clinton.
He said global warming was something China had invented to reduce the profitability of US companies.
"He can stop the payment of US tax dollars because it's his job to issue payments," says Dr Reinhardt.
"But he cannot just pull out of treaties because it is the job of Congress to join treaties."
If he has enough agreement in Congress, it's possible that he could change things pretty drastically.
Gina's verdict: It's possible
Climate change denial
He's previously pledged to restrict Muslims entering the US
"Donald J Trump is calling for a total and complete shutdown of Muslims entering the United States until our country's representatives can figure out what is going on," said the man himself during the election campaign.
Dr Reinhardt says this one is complicated.
As president he will be "in control of the border patrol and immigration".
But, she says: "That sort of law is incredibly controversial. It would, without a doubt, be taken to the Supreme Court and be judged unconstitutional."
She points out that even President-elect Trump moved away from this idea as the campaign went on, instead calling for "extreme vetting" of Muslims entering the country.
Expert verdict: There'll be no ban on Muslims
And he will have control of America's nuclear codes
Barack Obama raised concerns about President-elect Trump getting access to the nuclear "button" after it was rumoured Trump's team had banned him from tweeting.
"If somebody can't handle a Twitter account, they can't handle the nuclear code," President Obama said.
The new commander-in-chief will indeed have ultimate power.
"He will be in charge of the nuclear code. He will be capable of launching nuclear weapons," says Dr Reinhardt.
Expert verdict: Yes, Trump will be in control of any possible American nuclear strikes