The bad news is that there will be more extremes within
those averages – searing high-temperature droughts and downpours causing
flooding.
"The kind of changes one anticipates are more
likelihood of drought or more likelihood of wet periods," said Greg Flato,
Environment Canada's top climate modeller.
"If you think about temperature extremes, as the
climate warms the likelihood of getting a very hot extreme becomes greater; the
likelihood of getting a very cold extreme becomes less likely."
The extra rain, for example, is unlikely to fall in a gentle
spring shower. Look for it in great flooding downpours or winter rains that
drain before they can nourish crops.
John Pomeroy, a Canada research chair in water resources at
the University of Saskatchewan, says that moisture from snow has already
declined by a third across the Prairies. The number of multi-day rains has
increased by 50 per cent.
"Farmers need to adapt to that, to being inundated and
flooded quite a bit," he said.
Heat-loving crops such corn could become much more common,
but they are more likely to run short of water.
"It complicates the U.S.-Canada relationship,"
said Rob Huebert from the Centre for Military and Strategic Studies at the
University of Calgary.
"We know that in the southwest (U.S.) they're pretty
much getting maxed out in terms of available water sources. In a United States
that is water-deprived, they're automatically looking northward."
Climate will be a hidden driver behind many difficult
foreign situations, said Huebert. Refugees, fleeing expanding African deserts
or the strife caused thereby, will be knocking on Canada's door.
