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The Changing Climate of Canada: Implications for Agriculture
Reference
Qian, B., Zhang, X., Chen, K., Feng, Y. and O'Brien, T. 2010. Observed long-term trends for agroclimatic conditions in Canada. Journal of Applied Meteorology and Climatology 49: 604-618.

What was done
Working with an homogenized temperature dataset consisting of daily maximum and minimum air temperatures obtained from 210 meteorological stations distributed across Canada that cover the period 1895-2007, plus an adjusted precipitation dataset developed at the Climate Research Division of Environment Canada, the authors derived a set of agroclimatic indices representing Canadian climatic conditions, which they analyzed for trends that are sure to prove useful for agricultural production planning purposes for many years to come.

What was learned
Qian et al. say their results indicate "a significant lengthening of the growing season due to a significantly earlier start and a significantly later end of the growing season," and they say that "significant positive trends are also observed for effective growing degree-days and crop heat units at most locations across the country." They also report that "the occurrence of extremely low temperatures has become less frequent during the non-growing season, implying a more favorable climate for overwinter survival," and they find that "the total numbers of cool days, frost days, and killing-frost days within a growing season have a decreasing trend," so that "crops may also be less vulnerable to cold stress and injury during the growing season." In addition, their work reveals that "extreme daily precipitation amounts and 10-day precipitation totals during the growing season have been increasing," and that "significant trends associated with increased availability of water during the growing season are identified."

What it means
These several desirable results clearly indicate that the "deadly" global warming that brought an end to the debilitating cold of the Little Ice Age and ushered the planet into the Current Warm Period is proving to be a real boon to Canada, as well as to the rest of the world, which may have to depend upon North America's northernmost country to supply a significant portion of the food it will need to support its growing numbers in the years and decades to come.

Reviewed 29 September 2010