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Climate and Drought in the Canadian Prairie Provinces
Gan, T.Y.  1998.  Hydroclimatic trends and possible climatic warming in the Canadian Prairies.  Water Resources Research 34: 3009-3015.

The author introduces his study by noting that the severity and frequency of extreme events like flooding and prolonged droughts seem to be on the rise globally.  He then rightly notes that "we are not yet able to determine causal relationships between extreme events and climatic warming," but he goes on the state that the possible presence of a causal relationship "should be of interest to scientists and politicians all over the world," which indeed it is.  Noting that there are some indications of warming in some seasons of the year in western Canada since 1949, he then states the research question he has chosen to address within this context: "If climate change is real, what are the likely impacts for the Prairie drought?"

What was done
A number of statistical tests were conducted on data sets pertaining to temperature, precipitation, spring snowmelt dates, streamflow, potential and actual evapotranspiration, and the duration, magnitude and severity of drought in the Canadian Prairie provinces of Alberta, Saskatchewan and Manitoba.

What was learned
The results of the several statistical tests suggest that the Canadian Prairies have become somewhat warmer and drier over the last four to five decades, although there are some regional exceptions to this generality.  However, when all pertinent factors are weighed in the balance, the case is extremely tenuous; and the author states that "there is no solid evidence to conclude that climatic warming, if it occurred, has caused the Prairie drought to become more severe."

What it means
Drought is a natural feature of the Canadian Prairie region, which has experienced at least twenty serious droughts in the nineteenth century and ten in the twentieth century, as the earth has slowly recovered from the global chill of the Little Ice Age.  This global warming phenomenon thus appears to have reduced drought somewhat over the past two centuries in the region of the Prairie Provinces.  For the last fifty years of this period, however, what little further warming may have occurred appears to have had no additional ameliorating effects.  On the other hand, this study also demonstrates that recent warming cannot be blamed for the possibly slightly drier conditions of the past half century.  As a result, the author answers his own question about the future by stating that "the evidence is insufficient to conclude that warmer climate will lead to more severe droughts in the Prairies."

Reviewed 15 December 1998