Canada's rate of warming is about twice the global rate, according to a climate change briefing presented to the country's premiers on Monday.

For the first time in nearly seven years, federal, provincial and territorial leaders gathered together in Ottawa with Prime Minister Justin Trudeau. Their meeting comes a week before the start of the UN climate change conference in Paris, known as COP21.

Greg Flato, senior research scientist with Environment Canada, told the premiers the science behind climate change is 'conclusive.' (CBC)

Alain Bourque, the executive director at Ouranos, a consortium on regional climatology and adaptation to climate change, told the first ministers an increase of two degrees in average temperatures globally could mean that Canada would see a change of about three to four degrees.

Bourque said climate change will be felt differently in Canada. Warmer summers could mean more forest fires, like those Western Canada experienced last summer. Parts of Canada could also see more droughts and deadly heat waves, he told the gathering.

The presentation, available on Environment Canada's website, summarizes the key science behind climate change.

"Warming over the 20th century is unequivocal and largely due to human activities, including the burning of fossil fuels," Bourque said.

He told the group the effects of climate change will persist for centuries, because greenhouse gases are long-lived and the oceans are warming.

Alain Bourque, the executive director at Ouranos, told the premiers that climate change will be felt differently in Canada, with a higher average temperature increase. (CBC)

Greg Flato, a senior research scientist with Environment Canada, wouldn't comment on what policy changes the government should adopt, but he said a reduction in greenhouse gas emissions is needed to stabilize temperatures.

"Warming is unequivocal and human influence on the climate system is clear. Impacts of a changing climate are already being felt, and they will increase with further warming," he said. "The science indicates that reducing greenhouse gases are what is needed in order to stabilize temperature at some level, and that the amount of CO2 emissions, there's a cumulative budget that you can emit in order to keep the global temperature below a certain value."

Flato noted how unusual it was for scientists to brief the premiers and prime minister and then hold a press conference.

"It's certainly not like my normal day at work," he said with a laugh. "It was pretty remarkable, and it was a pleasure to be able to do it."