Canadian expert warns about effect of climate change on water cycle and extreme weather

This week, 100 experts from around the world are meeting in Banff, Alberta, at a conference called 'Storm Warning: Water, Energy, and Climate Security in a Changing World', and one of the conference speakers has a dire message regarding the effects of rising temperatures on the snow pack and on the hydrological cycle.

Robert Sandford, the Director of the Western Watersheds Climate Research Collaborative (WWCRC) and EPCOR Chair for the Canadian Partnership Initiative of the United Nations 'Water for Life' Decade, gave a talk to the conference on Tuesday night titled 'The Snows of Yesterday and the Future Water Supply of the Canadian West', where he discussed how the loss of the snow pack and glaciers is effecting the availability of water, how rising temperatures are energizing the water cycle, and how these changes are causing computer models to lose the ability to predict how water is going to behave — what hydrologists call 'the loss of hydrological stationarity'.

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"We're talking about how warming temperatures are affecting the depth of snow cover, the depth of snowpack, the length of time when it is there and the effect of these changes on glacier mass, which is to say how much snow is available to feed and sustain these glaciers." said Sandford, according to CityNews.

"It's clear that the trend is continuing and we're now very concerned from research that has been collected that it might be accelerating," he said. "If we had this conference 10 years ago we'd still be dealing with projections with a lot of anxiety about how accurate the projections were. We're no longer looking at models — we're seeing widely demonstrated examples."

One well established fact about the atmosphere is that warmer air can hold more moisture. Thus, as temperatures rise due to the increase in greenhouse gases in the atmosphere, the water vapour content of the atmosphere will increase, and this will set off a 'water vapour feedback', where the increase in water vapour — one of the strongest greenhouse gases — will increase the warming already experienced due to the other greenhouse gases, which will, in turn, increase the amount of water vapour in the atmosphere, and so on. All this extra water vapour in the atmosphere will be at the expense of water locked up in the snow pack, and in the ground, and this is expected to disrupt the water cycle.

"What we're seeing as a consequence of that is more extreme weather events," said Sandford. "In 2005, for example, there was a two-hour storm in Toronto that caused $700 million worth of damage, mostly water-related and transportation infrastructure."

The storm in question dumped over 150 mm of rain on some areas of the city. It overwhelmed sewers and storm drains, and caused the part Finch Avenue that passes over Black Creek to collapse.

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Sandford also talked about "massive water vapour rivers" moving water around the world to places where it doesn't usually go, causing heavy rains in California, and flooding in Australia and Pakistan.

Fixing the problem will take more than reducing carbon dioxide emissions, according to Sandford. Slowing or minimizing the current trend will require efforts towards restoring the ecology. As with most things of this nature, action is needed sooner rather than later.

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