Is This A Mega-Drought?

A research scientist who has spent much of his life studying the effects of drought and floods on the Canadian landscape says that current drought conditions, which are most severe in much of western North America, have been building for several years now.

Dr. John Pomeroy is the Canada Research Chair of Water Resources at the University of Saskatchewan. His research involves the impact of climate change on land use and water security in cold and semi-arid regions.

Dr. Pomeroy explains that Prairie agricultural practices have always been placed in the category of dry-land farming, so periods without rain events are viewed as normal. But he says this weather event is shaping up differently, simply due to the vast scope of the geographic region being affected.

“This is something that I would term a Mega-drought. This drought extends across Canada, from southern Quebec to Vancouver Island, then also south. The greatest severity is actually in the south-western United States, with the second severe area in North Dakota which extends into Saskatchewan and Manitoba. Last summer was very dry in many parts of the Prairies and then a relatively dry winter. And that means moisture-depth in the soils is very, very low. We’ve already lost pot-hole slues in many of the wetlands and some of the dug-outs have gone dry. Many of them were simply dry in May.”

Professor Pomeroy says that weather patterns, especially in the Prairies, have changed dramatically over the past four or five decades. Easy-inch showers have been replaced with severe down-pours and warm, dry weeks have been replaced by months of scorching weather.

“In western Canada the nature of rainfall has changed. Rainfall in the summer is clustered more now, than it use to be. If you go back to the 1920’s or 30’s, you get a rain on a day and then a few days dry. Now we tend to get more multiple-day rainstorms, with longer periods without rain in between. And more extreme precipitation when it does come. The number of multiple-day rainstorms has increased 50 percent in the Prairie Provinces since the late 1950’s. So, this is quite a difficult prescription for producers on the land.”

There has been much talk that climate change is a welcomed by Canadians tired of suffering through long, cold winters and short summers. But Dr. John Pomeroy says the speed and the extent of those changes will make adaptation to this new Canadian normal hard to manage.

“The amount of climate change predicted for Canada is much greater than for the rest of the world, and warming more rapidly than other parts of the world. We have to be prepared for that. We’ll see dramatic changes including water shortages in the summer. We also have to be able to take advantage of that heat in the right way.”

Dr. John Pomeroy is the Canada Research Chair of Water Resources at the University of Saskatchewan.

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