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Feature

An opossum.

Once rare in Minnesota, opossums have been rapidly moving north.

Winter is losing its bite

With winter losing its bite, life in the Frozen North just isn't the same

By Deane Morrison

From M, spring 2007

When Minnesota ice fishing tournaments are canceled for lack of ice, you know it's a mild winter-again. Mark Seeley, a University meteorologist and state climate history expert, says the change in winter is for real. "Although we can always find warm winters, we can't find a string like the last nine," says Seeley, author of Minnesota Weather Almanac. The changes are in line with predictions by models of global warming. Based on average temperatures, January 2006 was the warmest since 1846, and December 2006 tied for fourth warmest in state history. That's a far cry from December 1983, the coldest of the 20th century.

So that's an opossum!
The nonhuman residents of Minnesota change with the climate


As winters shrink and the climate warms up, state populations of many animals and plants are shifting:
>>Opossums. North America's only marsupial has been moving rapidly north, turning up in roadkills throughout the Upper Midwest.
>>Birds. Cardinals, once unseen in Minnesota, now live on the North Shore and in Canada. The Carolina wren and the blue-gray gnatcatcher have also made themselves at home in our state. Loons may be migrating back earlier, and may--possibly--stick around if lakes remain ice-free. But, says the American Bird Conservancy, climate change could rob Minnesota of 36 bird species while adding only five. Many of the losses will be warblers of the northern forests, which are threatened by climate change and other factors.
>>Insects. More bean leaf beetles and European corn borers will survive our winters, which bodes more damage to soybean and corn crops.
>>Gardeners may wonder if plants adapted to USDA hardiness zone 5 can now be grown in parts of Minnesota long rated zone 4. The answer is unclear. If you want to experiment with zone 5-rated plants, go ahead, but try an inexpensive perennial such as a Korean spice viburnum, forsythia, peony, or iris. Don't risk $300 on a Japanese maple or fruit tree. The USDA hardiness zones are undergoing revision.

The relative heat wave means we're burning less fossil fuel in our furnaces, too. "At present energy prices, some people would be paying a monthly heating bill equivalent to a mortgage payment" if December 1983 were to repeat itself, Seeley figures. Municipalities are spending less on snow removal, and schools and businesses close less often. The weather also means a longer construction season for contractors, a longer biking season, and even winter golfing. The lack of snow is in part a cause, as well as an effect, of our warm winters. "You don't get record setting warm winters with snow," says Seeley. Snow reflects solar radiation, helping the air around it stay cold. But bare ground soaks up the heat, warms the air, and contributes to further snowmelt. As more northern land goes snow-free in winter, it helps accelerate global warming. As temperatures rise, Minnesota may be seeing more freezing rain and sleet. And no longer is March the snowiest month; with more March precipitation falling as rain, January has taken the top spot. "This can help alleviate the spring snowmelt effect," says Seeley, referring to the flooding that follows a large, rapid snowmelt. Records begun in 1895 show that 10 of the 20 warmest November-March intervals have occurred since 1981. Higher minimum temperatures, which usually occur at night, seem most responsible. In his book, Seeley writes that southeastern Minnesota counties' average daily minimum for February rose from 8.2 F for 1951-1980 to 11.7 F for 1971-2000. "That's a change of 3.5 degrees, large in comparison to changes in maximum temperatures, which are typically just a few tenths of a degree," he writes. This small change has hurt ski operations, outdoor hockey, and skating. Even car mechanics are feeling the heat. "My mechanic said that during the '70s and '80s, a huge part of his income was installation of engine block heaters," recalls Seeley. "They've all but disappeared."