Canada is warming twice as fast as the rest of the world.
The warming is "effectively irreversible," a scientific report from Environment and Climate Change Canada says.
The Canada Press reports that at stake is how bad it gets, said several scientists presenting the Canada's Changing Climate Report.
The report is based on the work of 43 federal and university-based scientists who reviewed published scientific literature over the last two years.
"We are already seeing the effects of widespread warming in Canada," said Elizabeth Bush, a climate-science adviser at Environment Canada. "It's clear, the science supports the fact that adapting to climate change is an imperative. Urgent action is needed to reduce emissions."
The report says the average temperature in Canada is 1.7C higher today than it was 70 years ago, while the average global temperature is up 0.8C.
There is a worse increase in the Canadian Arctic - 2.3C.
That means there is a risk that by the middle of this century most marine regions in the Canadian North will be ice-free for at least a month at a time, the Canadian Press reports.
Warming is happening even faster in winter, with a 3.3C average temperature increase between December and February, leaving southern Canadians with more winter rain and northern Canadians with melting permafrost and less sea ice.
More rain and less snow could have a significant impact on the availability of fresh water in parts of the country, particularly in the summer, the report notes. Snow that accumulates but doesn't melt until later in the year is effectively banked water.
Warmer winters also mean certain species that can't survive our winters now will start to do so, bringing pests and diseases to Canada we aren't used to seeing.
Bush said there are two different scenarios for Canada depending on whether the world makes significant progress towards cutting net greenhouse-gas emissions to zero by 2050.
The report shows if the world can do that, the average temperature increases in Canada by the end of the century will be less than 3C even in the hardest-hit parts of the country.
If the world keeps emitting at the same rate, most parts of Canada will see increases of between 7C and 9C, with the far reaches of the Arctic seeing temperature changes in excess of 11 C.
"We are kind of at this fork in the road," said Chris Derksen, an Environment Canada research scientist.
In the worse scenario, Canada will see 10 times as many deadly heat waves and twice as many extreme rainstorms, the report says.