Appearing for the first time on the campaign trail in 2016 in the race for the White House, former Vice President Al Gore joined with Hillary Clinton at a rally in Miami, reminding supporters of his close defeat in Florida that year, as he urged voters to get out and vote and defeat Donald Trump in November.

"Your vote really, really, really counts - you can consider me as exhibit A of that," Gore said, as some in the crowd chanted, "You won!"

"Please take it from me, every single vote counts," Gore added with a chuckle, invoking the messy end to the 2000 election which saw Democrats lose in Florida by just over 500 votes.

Gore used his time at the Clinton rally to jointly argue that Donald Trump is not the right choice for Americans who are worried about the environment of the Earth.

"We cannot risk putting a climate denier in the White House," Clinton said to cheers.

"Donald Trump is quote,'not a big believer in climate change,' Clinton said. "He says it's a hoax."

"Hillary Clinton will make solving the climate crisis a top national priority," Gore said, as he argued Trump would be a "climate catastrophe" if he's elected to the White House.

Meanwhile, for a second straight day Clinton was interrupted during a rally by a protester who was yelling about her husband, the former President, one sporting a "Bill Clinton is a rapist" sign.

Clinton campaigns on Wednesday in Colorado and Nevada.