North warming 'three times faster than much of world'

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Northern Canada is warming at three times the global average and will continue to get warmer, faster, a major report released on Monday concludes.

The report, commissioned by Environment and Climate Change Canada, says northern warming has been most pronounced in winter. It declares the overall change "effectively irreversible" at this point.

Authors of the report warn up to a fifth of deep permafrost in the North could disappear by 2090, "with impacts on northern infrastructure."

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Many of the report's findings suggest the North is expected to endure a climate of increasing extremes in the decades ahead, with consequent impacts on natural phenomena like wildfires.

Earlier on Monday, Bill Quinton -- a Wilfred Laurier University hydrologist -- told the CBC there are already "concerns about wildfires [and] their increasing frequency and magnitude."

Quinton has worked in the NWT for more than three decades, studying changes in permafrost at the university's Scotty Creek research station in the Dehcho.

Events like the territory's March heatwave, he told the national broadcaster, could no longer be considered isolated anomalies but were instead, increasingly, part of "a consistent story."

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"There's concerns about infrastructure in the towns and communities, and I guess this latest event is part of that," he said. "It's closing down ice roads, ice bridges, and there's economic impacts on communities."

Parts of the NWT reached 20C in March for the first time since records began. In Yellowknife, two events ordinarily held on a frozen bay -- Snowking's Winter Festival and the Long John Jamboree -- were significantly disrupted by the heat.

The full federal document is entitled Canada’s Changing Climate Report. Initially leaked to the media on Monday -- just as Ottawa's carbon pricing plan took effect in four provinces -- the report was later made available in full online.

In full: Read the Canada's Changing Climate Report

"Northern Canada has warmed and will continue to warm at even more than double the global rate," declares a paragraph summarizing temperature change across the nation.

"Temperature has increased in all regions of Canada and in the surrounding oceans. Since 1948, when nationwide records became available, Canada’s annual average temperature over land has warmed by a best estimate of 1.7C, with higher temperature increases observed in the North, the Prairies, and northern British Columbia.

"Annual average temperature over northern Canada increased by 2.3C since 1948. The greatest warming has occurred in winter."

The report asserts: "It is likely that more than half of the observed warming in Canada is due to the influence of human activities."

In the future, the report's authors forecast annual temperature in the North increasing by 1.8C if emissions are held in check, or up to 2.7C in what is dubbed a "high-emissions scenario."

With near-certainty, the researchers who produced the document state precipitation in the North will increase in decades to come -- often as summer rain, and more frequently as "extreme precipitation."

Sea level, in a high-emissions scenario, could increase in the Beaufort Sea region by up to 75 cm by 2100. Snow accumulation is expected to see only limited change, as "winter temperatures will remain sufficiently cold despite overall warming."

Throughout the document, the authors make clear their projections come with varying degrees of confidence depending on the underlying science and data being used.

However, all of the quoted projections related to the North are given with at least "medium confidence" and, frequently, a high level of confidence.

More detail: How the report was prepared

Reaching its conclusion, the report states: "Historical warming has led to changes in rain and snow, rivers and lakes, ice, and coastal zones, and these changes are challenging our sense of what a 'normal' climate is.

"Beyond the next few decades, the largest uncertainty about the magnitude of future climate change is rooted in uncertainty about human behaviour, that is, whether the world will follow a pathway of low, medium, or high emissions.

"Until climate is stabilized, there will not be a new 'normal' climate."