TORONTO - Global climate change could result not only in warmer summers over
the long term but also colder winters, according to some climate models.
The reason is average surface temperatures of the Earth are increasing, but it
isn't happening uniformly. In some places, such as Eastern Canada, temperatures
have actually been dropping, climatologists say.
The colder winter scenario is based on what happens in the Gulf Stream, a major
ocean current that brings warmer weather from the tropics up into the North
Normally, the Gulf Stream brings up dense, saline water in a process called deep
water formation. When the water cools, it sinks down into the ocean floor,
releasing heat at the surface. The heat warms the atmosphere, which is why
northwestern Europe is warm for its latitude.
University of Toronto physics Prof. Richard Peltier said a large influx of
freshwater into the North Atlantic could reduce the rate of deep water formation
during the winter. There's no consensus on whether this will happen, Peltier
If it happens, winters could be "significantly colder" than this year's freeze
in Central and Eastern Canada, Peltier said.
As for this winter's heavy snowfall and freezing temperatures, Peltier reminds
Canadians that climate change involves variation in weather over hundreds of
years, not a few seasons.
The cold winter is part of the large natural fluctuations we've always seen
over decades, he said.