Wildrose Leader Danielle Smith came under fire Thursday at the CBC Leaders' Forum for her insistence that the science behind climate change hasn't yet been settled.

"We've been watching the debate in the scientific community and there is still a debate in the scientific community," Smith said, prompting jeers from the audience who watched the forum at CBC Edmonton.

Smith, who first made the comments in an online leaders' debate earlier this week, has come under criticism for holding this view. Progressive Conservative Leader Alison Redford — whose party is trailing Wildrose in the polls after 41 years in power — suggested Smith's position could hurt the Alberta economy.

"When I go to Washington and I talked to people in the White House and I'm trying to talk to them about why we need Keystone [pipeline], they don't want to hear that I don't believe in climate change," Redford said.

Wildrose Leader Danielle Smith (left), Liberal Leader Raj Sherman, Progressive Conservative Leader Alison Redford and NDP Leader Brian Mason participated in a one-hour forum at CBC Edmonton on Thursday. (Jason Franson/Canadian Press)

"They want to know that they have a premier and a leader from this province who's prepared to understand that this impacts our markets, this impacts our investors and if we don't take it seriously, it's going to impact our economy and our way of life."

NDP Leader Brian Mason said the majority of scientists agree that climate change is real.

"The only people that are disputing it are the phoney scientists funded by the oil industry," he said.

Smith, Redford, Mason and Liberal Leader Raj Sherman also took questions during the lively one-hour discussion about health care, seniors housing, moral issues and implementing a provincial sales tax.

It was the first and only time for the public to see all four leaders in the same place at the same time.

Sherman calls Wildrose, Tories 'false choices'

Both Mason and Sherman are trying to fight a recent suggestion by some that centrist and left-wing Albertans should vote strategically for the Tories to keep the Wildrose out.

"Do we really have to vote for two false choices?" Sherman asked. "A bunch of bullies who have been wrecking our health and education democratic systems and a bunch of bigots who want to further wreck our health and education systems?"

Most of the narrative around the campaign has centred on the battle between Redford — the leader of a party that has governed Alberta since 1971 — and Smith, the so-far unelected leader of the upstart Wildrose Party, which sits further right of the Alberta Tories on the political spectrum.

With the election looming on Monday, both women are aiming for a strong finish.

"I think one thing that the opposition leaders will all agree on is that is not a government that deserves to have another majority," Smith told the forum.

Redford tried again to distinguish her party as more progressive than the Wildrose.

"I don't know how the people that I'm asking to vote Progressive Conservative on Monday have voted before, but from my perspective we're asking people to make a positive vote for the future of this province," Redford told reporters afterwards.

Thursday's forum was broadcast on CBC-TV and Radio in Alberta as well as livestreamed on the CBC Edmonton, CBC Calgary and Alberta Votes websites.