|
|
The melting of
Minnesota
Bill McAuliffe, Star Tribune
March 20th, 2006
OSAKIS, MINN. --
Norman Clyde is puzzled by the sight of the fishing shack still for
sale in front of his bait shop. Last year, he sold six on the same
spot. This year, he can't sell one.
Granted, Clyde was competing with the warmest January in at least a
century. Out on Lake Osakis, a popular fishing spot in central
Minnesota, there were half the usual number of shacks, and sheets of
water lay over thin ice. In town, despite the completion of a new
trail, snowmobile traffic was scant.
Clyde can live with one odd month. But he and others have come to
suspect something larger than an extended January thaw is at work.
Across
Minnesota,
there's a growing conviction that what's happening on the lakes, in
the woods and in back yards is linked to warming patterns evident
around the world.
"We keep thinking every year when something like that happens, it's
an anomaly,"
Clyde
said. "But it's been getting stranger and stranger every year."
Clyde said it doesn't surprise him that state climatologists, using
almost 140 years of data, have determined that Lake Osakis now
breaks open in the spring, on average, a week earlier than it did a
century ago.
Kim Lucas, a veteran of 40 winters fishing on the ice, said the same
thing.
"We don't have that old-fashioned winter anymore, when things really
got cold," he said. "Something has turned."
In northwest
Minnesota,
U.S. Fish and Wildlife Service scientists cite warming as a reason
why a moose herd that 20 years ago numbered nearly 4,000 may soon
disappear. In the Boundary Waters Canoe Area Wilderness, foresters
are noticing that maples and oaks more suited to warmer climates are
taking hold. Near St. Peter, naturalist Jim Gilbert says lilacs are
blooming in the spring two to three weeks earlier than when he first
began watching them in 1967. In
Dakota
County,
parks officials no longer schedule skiing and snowshoeing events for
December and January, for lack of snow.
Those examples are reinforced by a pile of meteorological data
showing that the state has been getting warmer and wetter for some
time. No one's panicking, but when winter itself is under siege,
climate change in Minnesota becomes a question of identity.
Greta Petrich, who reports the Lake Osakis ice-out dates to the
Department of Natural Resources, said local dealers are switching
from selling snowmobiles to selling all-terrain vehicles. "Change or
die," she said.
Brian Bahn, who works for Midwest Mountaineering in Minneapolis,
said recently that he finds it "hard to look somebody in the face
and sell them snowshoes."
The Minnesota Department of Tourism, responding to the recurring
mild winters, produced a video promotion this season that for the
first time features indoor activities, not just ways to enjoy snow
and ice. The spots show an actor in a bear suit ice fishing and
snowmobiling, but also browsing in an art gallery and making moves
on a dance floor.
Concerns about extreme heat
In the Twin Cities, concerns about climate change in the summer,
too, have prompted government, social service and health agencies to
develop a hot weather emergency response plan. Rescue workers and
those who work with the elderly would check on vulnerable people
during heat waves.
"I've lived here since 1982, and when the trees start re-budding in
November and the winters are lame like they have been, and each
summer it seems the heat comes earlier and stays longer. ... I just
think it's unfortunate we have to think extreme heat could have
devastating consequences on people's health in
Minnesota,"
said Pam Marshall, executive director of the Energy Cents Coalition,
which helped develop the heat-wave emergency program. "But it's
creeping north."
What's driving the changes?
The warming of the Earth is widely attributed to three things:
natural, long-term climate variation; alterations to the landscape
such as spreading cities and forest clearing, and a buildup of
heat-trapping gases -- primarily carbon dioxide, methane and water
vapor, known as "greenhouse gases" -- in the atmosphere.
It's the carbon dioxide (CO2) buildup that gets most of the
attention, because it's linked to the burning of fossil fuels for
electricity, heating and transportation. The Intergovernmental Panel
on Climate Change, an international group of scientists commissioned
by the United Nations, concluded that CO2 in the atmosphere has
increased 30 percent increase since industrialization took hold in
the mid-19th century.
The group, as well as the National Academy of Sciences, attributes
that buildup to human activities.
In Minnesota, emissions of CO2 rose at four times the global rate,
and 28 percent overall, from 1990 to 2004, according to the
Minnesota Pollution Control Agency.
The U.S. Environmental Protection Agency cautions against drawing
conclusions about climate outcomes in specific regions. President
Bush also contends that uncertainties about the direction of climate
change still exist. But he has said he supports curbing greenhouse
gas emissions with new technologies that avoid economic disruption.
The causes and effects of the warming so far have been most dramatic
in the Northern Hemisphere, because it has a higher proportion of
both people and land -- which reflects heat, rather than absorbing
it. And places far from oceans, such as
Minnesota,
are thought to be positioned for some of the most extreme changes.
At high latitudes and altitudes around the world, polar ice and
mountain glaciers are melting and retreating at unprecedented rates.
In
Alaska, warming ground temperatures are thawing what had been
permanently frozen soil, opening sinkholes, shrinking lakes and
toppling trees and houses.
Meanwhile,
Minnesota's
annual average temperatures have been rising faster than the rest of
the globe's -- some say twice as fast. The state Office of
Climatology has calculated the rise at 1.8 degrees Fahrenheit since
1894. That's four times the variation the globe saw over the
previous three to five centuries.
A study of the moose decline in northwest Minnesota found that
between 1960 and 2001, temperatures in the area increased 12 degrees
and winter and 4 degrees in summer. Climate change research predicts
that global temperatures could rise between 2 and 10 degrees or more
this century.
Shorter ice seasons could change the character of Minnesota lakes.
With more time for evaporation, water levels could drop. Warmer
lakes could release trapped pollutants and create metabolic problems
for cold water fish, including Minnesota's favorites -- walleye,
northern pike and trout, said Dr. Lucinda Johnson, associate
director of the Natural Resources Research Institute at the
University of Minnesota Duluth.
Next January, of course, could bring record cold. But Minnesota has
been warming in both the short and long runs. For the Twin Cities,
four of the five warmest winters since 1891 have occurred in the
past 24 seasons. Four of the nine warmest have happened over the
last nine winters, including this one.
According to
University
of
Minnesota Extension
meteorologist and climatologist Mark Seeley, the recent trends have
been marked by warm winters, warm summer nights and high dew points.
Elevated dew points -- a measure for human discomfort that also
reflects plant vitality -- have increased in frequency and duration
over the past 20 years. Dew points last July in Minnesota, Seeley
noted, resembled those commonly recorded in
Bombay,
India.
Average annual precipitation -- often overlooked in discussions
about climate changes -- has increased even more sharply than
temperatures across Minnesota. Because of its connection to
increased water vapor in the atmosphere, elevated precipitation is
one of the central predictions in many global warming studies.
Hard times for a moose herd
Apart from the weather data, the moose decline in northwest
Minnesota and the changing forest in the Boundary Waters are some of
the most tangible evidence researchers have attributed to the
warming climate.
The once healthy northwestern herd of moose has dwindled to fewer
than 250, federal researchers have found. They tracked the animals
with radio collars and determined that a number of ailments,
including parasites possibly spread by deer, were killing the
animals.
But a 2004 report on the moose decline also noticed an increase in
mortality following hot summers, and deduced that the moose were
weakened by having to use up energy keeping cool.
"The study concluded that climactic changes combined with increases
in deer numbers and parasite transmission rates may have rendered
northwest Minnesota inhospitable to moose," the report said.
Seeding an oak savannah?
On another front, Lee Frelich, director of the Center for Hardwood
Ecology at the
University
of
Minnesota,
first detected the growth of red oak and red maple seedlings along
the Canadian border in 1992.
While some climate scientists have predicted that the northern pine
and birch forest could vanish altogether, Frelich said the red oak
and red maple could replace it if the warming climate trend includes
enough moisture. If the climate trend goes warm and dry, he said,
the area could come to resemble oak savannah -- grassy prairie with
intermittent stands of oak trees.
Seeley, the
University
of
Minnesota
climatologist, said he objects to fixating on whether humans are
completely to blame for warming. That distracts from discussions on
what to do about it, he said.
"Scientific nitpicking disguises the fact that our vulnerability is
not going away," Seeley told a group of farmers in southern
Minnesota this month. "That vulnerability is almost a national
agenda item. It's of more economic consequence than ever."
Polar explorer Will Steger and the advocacy group Minnesotans for an
Energy Efficient Economy argue that Minnesota could benefit from
trying to blunt global warming. They say moving away from fossil
fuels could provide a significant boost to the state's wind and
biomass energy industries.
The National Academy of Sciences, and Minnesota climate scientists
such as Seeley, also say a warmer climate could bring benefits:
lower heating costs and energy use, increased yields for some
farmers and more time for summer recreation. Some evidence also
suggests increased CO2 may actually enhance some plant life, trees
in particular.
For places that thrive on recreation in ice and snow, however, the
winter warmth isn't welcome. Last year, Lake Osakis shed its wintry
armor on April 8, eight days ahead of the April 16 average.
Earlier this month, anglers were driving full-size pickup trucks
onto the lake. They still needed to drill through 2 feet of ice to
find sunfish and crappies. But last week, Petrich noticed slush on
the surface of Lake Osakis. After an inspection Friday, she
predicted it will be gone on April 8 once again.
For Kim Lucas and the few other anglers out fishing on the lake this
time of year, the warming is bringing other changes. He had a
baseball cap on -- not a winter hat -- out there one day this month.
And they all expect to be moving to other lakes before long, heading
farther north in search of a receding winter.
Bill McAuliffe 612-673-7646 |
|
