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Canada says global carbon pollution must be reduced to 'near zero' to limit harsh impacts

#976 of 2552 articles from the Special Report: Race Against Climate Change
Water levels rise dangerously high below the Chaudière Bridge over the Ottawa River, between Gatineau and Ottawa, following spring flooding on May 8, 2017. File photo by Alex Tétreault

Canada is heating up at double the average rate of the planet, according to a stunning peer-reviewed scientific report involving dozens of government and academic authors, and it is likely that the majority of this warming was caused by human activities like burning fossil fuels.

Canada’s Changing Climate Report, released April 1, 2019, shows how climate change has already altered Canada and is expected to lead to heightened risks of heat waves, wildfires, floods and declining freshwater availability.

It found that Canada’s annual temperature over land has warmed on average 1.7 degrees Celsius between 1948 and 2016, while the average winter temperature has increased by 3.3 C. Although not uniform, that’s much more dramatic than the average warming around the world of between 0.8 C and 1.2 C as assessed by the Intergovernmental Panel on Climate Change.

For Northern Canada, the number is even starker: the region has warmed by 2.3 C, about three times global warming.

It also found more than half of the warming in Canada is "likely" due to human factors like burning fossil fuels such as gasoline that come from oil, gas and coal, which create heat-trapping carbon pollution.

The report uses careful language to express varying levels of confidence in scientific research, showing how climate change has already altered Canada & is expected to lead to heightened risks of heat waves, wildfires, floods and declining freshwater

The report is an overview and synthesis of published literature, similar to how the IPCC functions. As a result, it uses careful language to express varying levels of confidence in scientific research.

Overall, the scientists found the effects of climate change evident across the country, and that further warming over the next decades is already baked in due to pollution that has already been released into the atmosphere.

The only question is how extreme future changes will be. Scientists said while some further warming is "unavoidable," the amount "depends directly on global emissions."

"Scenarios with limited warming will only occur if Canada and the rest of the world reduce carbon emissions to near zero early in the second half of the century and reduce emissions of other greenhouse gases substantially," reads the report.

This graphic shows observed changes between 1948 and 2016 in annual temperature across Canada. The graph makes clear that Canada has warmed on average 1.7 degrees Celsius, but not uniformly. CCCR 2019 screenshot

The groundbreaking findings also include the following:

  • Get used to rain and urban flooding: Annual precipitation is increasing in many regions. Outside of the North, there has also been more rainfall in winter, as opposed to snow. More intense rainfall increases urban flooding risks. Annual and winter rain is projected to increase across Canada.

  • Wildfires, heat waves are the new normal: Extreme warm temperatures have become hotter, and extreme cold temperatures are less cold. Hot and cold extremes are projected to continue in the future. That means increased risk of extreme fire weather and heat waves.

  • Canada is losing its snow and ice: The proportion of Canadian land and marine areas covered by ice and snow has dropped over the last three decades, scientists found. There is less snow cover in fall and spring, glaciers are thinning, Arctic lake ice is lasting less long, and permafrost is warming. Snow cover is projected to drop in the next decades.

  • Oceans are rising and coasts will be hit: Coastal flooding is expected in the Atlantic, Pacific and the Beaufort coast in the Arctic due to the encroaching seas, which are projected to continue rising. In some areas like Hudson Bay, local sea level is projected to fall. Sea ice loss will allow more storms and waves to threaten more coastal infrastructure.

  • Freshwater will be threatened: Despite the increase in rainfall, the availability of freshwater is changing and leading to a higher risk of a water supply shortage. That is in part because the increased winter rainfall means a smaller snowpack left over in spring, leading to less runoff and lower summer flow. Warmer summers will also evaporate more surface water.

  • Marine ecosystems also threatened: The oceans, which have absorbed almost all of the excess heat generated from carbon pollution, are warming and acidifying. That process is expected to intensify with more carbon pollution and threaten the health of marine ecosystems.
This graphic shows the seasonal trends of snow cover and sea ice concentration for 1981 to 2015. The graphic demonstrates that in each season there has been a retreat of snow and ice, with the greatest occuring in the October to December period. CCCR 2019 screenshot

In general, scientists found that Canada will continue to experience greater changes in temperature, snow, ice, permafrost, freshwater, flooding, droughts and wildfires in the years to come.

“The science is clear: Canada’s climate is warming more rapidly than the global average, and this level of warming effectively cannot be changed,” said Nancy Hamzawi, assistant deputy minister for science and technology at Environment and Climate Change Canada.

“Global emissions of carbon dioxide from human activity will largely determine how much more warming Canada and the world will experience in the future. Reducing human emissions of carbon dioxide will reduce future climate change.”

Hamzawi spoke to media at a technical briefing the morning of April 1. The contents of that briefing were originally under embargo until April 2 at 1 p.m. Eastern Time. However, following the publication of a leaked version of the report on CBC News on Monday afternoon, the government lifted the embargo for all publications.

Fisheries and Oceans research scientist Blair Greenan speaks with National Observer in Halifax on Sept. 18, 2018. Photo by Alex Tétreault

Forty-three different government scientists and academic authors contributed to the report.

“Global sea level has risen and will continue to rise. The projected amount of global sea level rise by the year 2100...may exceed one metre,” said Blair Greenan, a research scientist of ocean stressors and Arctic science at Fisheries and Oceans Canada. “Therefore it is expected that coastal flooding will increase in many areas in Canada.”

The report is the first in a series expected as part of the current national climate assessment, called Canada in a Changing Climate, which was first launched in 2017. It covers the physical attributes. Other reports, such as on the impacts to human health and so-called national issues related to financial ramifications, are forthcoming.

As a result, scientists were not given the scope in this report to examine the impacts of global warming on the country’s economy, something the Bank of Canada is now investigating, or how the Trudeau government’s plan to price carbon pollution nationwide might mitigate the pollution that leads to warming.

Part of that carbon pricing system went into effect the same day that the report was released for the four provinces — Ontario, Manitoba, New Brunswick and Saskatchewan — that did not have a climate change plan that reached federal minimum standards.

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