The global reach of local weather conditions
Compared to the rest of the country, we’ve had a pretty mild winter. So far this year snowfall has been over 98 per cent below normal. According to Roger Pannett, volunteer weather observer for Environment Canada, for the 11th consecutive February total precipitation was below normal, a trend never previously observed.
In his Weather Report for 2012, Pannett said that with ten high temperature records and only one low temperature record, the mean temperature for last year was 0.36 degrees C above normal, continuing the general warming trend which began in 1986. And last year we had 14 days of maximum temperatures above 30 degrees C, double the average seven days for such temperatures.
Local warming weather trends are in line with what is happening globally and especially in the far north.
Canada’s glaciers are the world’s third biggest ice sheets behind Antarctica and Greenland. But according to research by scientists in the Netherlands and the U.S., they are heading for an irreversible melt. If just 20 per cent of the ice in Canada’s north melts, it will push up global sea levels by some 3.5 cm. Their report was published recently in the journal Geophysical Research Letters.
While a total melt of the world’s glaciers would take centuries, the speed of melt will accelerate in the coming decades as more bare land is exposed. With the ice cover and the albedo effect gone, the land will absorb the heat and further accelerate the regional melt. Large-scale deep thawing of permafrost will amplify the release of greenhouse gases such as methane, further accelerating warming.
In another study by 21 authors from 17 institutions in seven countries research showed that with the retreat of snow and ice in the north, seasonal temperatures and vegetation in Arctic regions are changing to more resemble landscapes found several degrees of latitude further south. Those findings were published in the journal Natural Climate Change.
“As a result of the enhanced warming over a longer ground-thaw season, the total amount of heat available for plant growth in these northern (circumpolar) latitudes is increasing,” said Dr. Compton Tucker, senior scientist, NASA’s Goddard Space Flight Centre, Maryland. “This created, during the past 30 years, large patches of vigorously productive vegetation totalling more than a third of the northern landscape – over nine million square kilometres – resembling vegetation that occurs further south.”
A key finding of the scientists is an accelerating greening rate in the Arctic and a decelerating rate in the boreal region. They theorize this may be because of complexities between growing season warmth and the fallouts from the greenhouse effect that include permafrost thawing, forest fires, drought, and increasing pest infections.
One thing the scientists all agree on is that the future looks troubling. Based on state-of-the-art climate modeling simulations, seasonal temperature and vegetation changes in the Arctic could resemble regions hundreds of kilometres further south throwing off course the flowering and fruiting of many plants that hundreds of species rely on in their seasonal migratory trek for food, nesting and breeding grounds. These changes will affect how an ecosystem will provide food and resources to local residents.
“The way of life of many organisms on Earth is tightly linked to seasonal changes in temperature and availability of food, and all food on land comes first from plants,” said Dr. Scott Goetz, deputy director and senior scientist, Woods Hole Research Center, Falmouth, Massachusetts. “Think of migration of birds to the Arctic in the summer and hibernation of bears in the winter. Any significant alterations to temperature and vegetation seasonality are likely to impact life not only in the north but elsewhere in ways that we do not yet know.”