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May/June 2003 issue	In this issue Table of Contents Editor’s Notebook Inside Story Feature: Eco-audit À la carte Mosaic Reverberations

Canada Dry
What a difference a year makes: satellite images reveal drought’s impact on Alberta farms and ranches
By Steven Fick and Eric Harris

Abnormally dry weather has depleted water resources across Western Canada for the past three years. Last summer, many municipalities in the southern Prairies were declared disaster areas. Two satellite images (below) of the same farmland — one from relatively rainy July 2001; the other from dry July 2002 — provide a graphic impression of drought near Wainwright in eastern Alberta, which suffered its driest period in almost a century.

Captured by sensitive scanners on Landsat-7, the 2001 image shows "healthy vegetation and crops with a biomass content somewhat less abundant than in a normal year," according to Carolyn Goodfellow of the Canada Centre for Remote Sensing. The parched-looking 2002 image shows vegetation with low chlorophyll content and healthy vegetation limited to where plants access water: along the Battle River and around creek beds, marshes, potholes and dugouts. Small and shallow lakes seen in 2001 are dry with fringes of vegetation in 2002.

The drought’s cause? Shifts in atmospheric circulation influenced in part by unprecedented warmth of the western Pacific Ocean, according to scientists at the National Oceanic and Atmospheric Administration in the United States. "The decades-long oceanic warming trend, likely a result of global warming," they report, "may be a harbinger of future severe and extensive droughts."

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