Wednesday, May 10, 2017

Historic flooding in Quebec probably linked to climate change: experts

http://montrealgazette.com/news/local-news/historic-flooding-in-quebec-probably-linked-to-climate-change-experts

Michelle Lalonde, Montreal Gazette Michelle Lalonde, Montreal Gazette
More from Michelle Lalonde, Montreal Gazette
Published on: May 9, 2017

Some may blame the gods, Hydro-Qu├ębec or their own bad luck, but climate change scientists say the heavy rains and terrible flooding plaguing Quebec this spring are almost certainly caused by global warming.

“There is a very clear picture emerging that we’ve changed the chemistry of the atmosphere with our greenhouse gases and we are really seeing the consequences now,” Paul Beckwith, a climate systems scientist who teaches at the University of Ottawa and Carleton University, told the Montreal Gazette in an interview Tuesday.

Record amounts of rain this spring in Quebec and Ontario have meant the soil is saturated and can’t absorb any more water. The run-off adds to the water levels in already bloated rivers and streams. Lake Ontario has now hit its highest recorded level since 1880, when record-keeping began. The St. Lawrence River is about 1.2 meters higher than it normally is this time of year.

Beckwith said the connections to climate change “are very clear.” First, the jet streams — those meandering air currents in the Earth’s atmosphere that flow west to east — are much wavier than they used to be. They are not moving as fast as they used to so they get stuck in position. And there is more water vapour in the atmosphere because it’s warmer and that water vapour rises and releases energy that fuels storms. Ocean temperatures are warmer, because of global warming, so there is a lot more evaporation and moist air coming onto the continent through the oceans.

“The net result of these jet streams behaving differently is that the occurrence of extreme weather events increases,” he said. “I’m talking about torrential rain causing flooding or droughts. The duration of storms increases because these storms get stuck over a region and don’t move out quickly, depositing all their water. And the intensity of storms are increasing because you have all that energy released from the extra water vapour in the atmosphere as it condenses into clouds.”

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But Steven Guilbeault, author of two books on climate change and an environmental activist who has focused on the issue since the early ’90s, said scientists have been telling the world for a long time that extreme weather events would increase.

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“We’ve known for 20 or 25 years that this was happening,” he told The Gazette. “What (scientists) got wrong was how fast. Twenty-five years ago we thought these things would start happening in 2040 or 2050. Very few scientists thought it would be happening so quickly. So what science is telling us is that the climate is much more sensitive to temperature increases than it was believed just two decades ago, 15 years ago, even 10 years ago.

“The number of natural catastrophes from forest fires to droughts have basically increased by a factor of four since the 1970s. So we can’t say that the (specific) flooding events we’re seeing is a result of climate change, but we can say that because of climate change these types of episodes and catastrophes are becoming more and more frequent.”

He said all the hardship that people in Montreal, Ottawa and other parts of North America are experiencing because of flooding may finally hammer home the urgency to tackle greenhouse gas emissions.

“When we look at polling or focus groups that are being done on the issue of climate change, we are seeing that natural catastrophes, especially when they hit closer to home, will get people’s attention.”

He said people in Quebec should focus on what they can do in their personal lives to reduce fossil fuel use, particularly when it comes to transportation. But more important is letting elected officials know that reversing climate change should be a priority on the municipal, provincial and federal levels.

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