"There is still a debate in the scientific community," said Smith before being drowned out by a chorus of boos and catcalls from hundreds of people who attended a leaders debate outside CBC's downtown studio.
"And we're going to continue to watch the debate in the scientific community," she said raising her voice to be heard.
The debate was the last chance for voters to see all four party leaders trading shots together on a stage before heading to the polls Monday.
Redford's right-leaning Progressive Conservatives are facing a serious challenge from the further-right Wildrose to their 40-year-old dynasty, dating back to 1971.
Polls put Smith's party out in front. But one recent survey suggested Wildrose had seen a large early lead over Redford's team slip somewhat as anti-gay comments from one Wildrose candidate, racist comments from another, and Smith's assertion on global warming made headlines.
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The Liberals have started calling the election a choice between "a bunch of bullies" and "a bunch of bigots."
The crowd at Thursday's forum was heavily weighted toward seniors and was a mostly NDP-partisan, judging from the decibel level of cheers when the individual leaders were introduced.
The climate-change debate was among the most spirited.
Emissions from Alberta's oilsands plants, along with its great inland lakes of toxic waste, have become the poster pictures for those who label Canada environmentally irresponsible.
The effects of those images were seen recently when environmental protesters helped block approval of the Keystone XL pipeline from Alberta to the United States on the grounds Canada needed to be sent a message to clean up its act.
It became an issue in the election campaign earlier this week, when Smith reiterated the Wildrose party's long-standing policy that the science of climate change is not settled.
Smith said despite her concerns, the Wildrose party would still take steps to reduce emissions through consumer rebates to spur investment in hybrid vehicles and energy efficient home retrofits.
"We're going to put in constructive policies," said Smith.
"Rebates are not going to fix this problem," NDP leader Brian Mason shot back.
"In my opinion, the science is completely settled. The only people that are disputing it are the phoney scientists funded by the oil industry," he said to cheers. "We need to get serious about it."
Mason said government needs to fix the problem at the industrial level with hard caps on emissions, moving away from coal-fired electricity generation, and funding more mass transit.
"There are a lot of things that could be done that should have been done a long time ago, but denying the science of climate change is just foolish."
Redford said if Alberta has a premier questioning climate change, it won't be taken seriously on the national or international stage.
"When I go to Washington and I talk to people in the White House, at Capitol Hill, and I'm trying to talk to them about why we need Keystone, they don't want to hear that I don't believe in climate change," she said.
"They want to know they have a premier and a leader from this province who is prepared to understand that this impacts our markets, this impacts our investors, and if we don't take it seriously it will impact our economy and our way of life."
Liberal Leader Raj Sherman said his party is also calling for hard caps on emissions, and said they aren't questioning climate change.
"Science informs our position," he said.
Recent polls have also suggest that traditional Liberal and NDP voters may be switching loyalties to the Progressive Conservatives as a palatable centrist alternative to block the right-wing Wildrose.
One video going viral on the Web depicts a young Alberta man admitting he'd rather have his face chewed off by rodents than vote PC, but will anyway to keep the Wildrose from the levers of power.
At the end of the debate, Smith urged people to vote straight up.
"You should vote in your heart who you think will best represent you in the legislature," she said.
"Having a government that has been in power for 41 years and created all of the problems that we have today, I think one thing that the opposition leaders will all agree on is that is not a government that deserves to have another majority."
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