The thickly frosted fields and hillsides of Michigan’s northern Lower Peninsula make it popular for winter sports vacations. Residents from urban areas such as metropolitan Detroit, Lansing and Grand Rapids go “up North” to ski, snowmobile and play in the snow.

But Michigan’s winters may be changing due to dramatically fluctuating temperatures. A unit of the National Oceanic and Atmospheric Administration that monitors Grand Traverse Bay ice conditions said for “the first time in at least 150 years…the bay had five consecutive winters without freeze-up.” Unusually warm winter temperatures have kept ski hills and snowmobile resorts unseasonably green instead of covered by feet of white snow. Even though some Michigan ski resorts make snow, warming trends are an indicator that the winter sports business may be in for hard times. Much of northern Michigan relies on cold weather and snow to bring tourists that provide winter resort revenues.

“The visiting season has shortened, primarily for snowmobile motels with miles and miles of groomed trails and no snow,” said Mark Zlupecki, owner of the Econo Lodge in Gaylord, Mich., whose winter customers are primarily snowmobilers. “Nine years ago, we opened the trails on Dec. 1 with two feet of snow. Last year there was no snow until Martin Luther King’s birthday [Jan. 15, 2004].” Michigan snowmobile sales have dropped nearly 50 percent since 1995, according to International Snowmobile Manufacturers Association data in the Michigan Land Use Institute report, “Global Warming Melting Michigan’s Snow Economy.”

Business owners in other cold-weather states are vulnerable to similar trends. According to the National Snow and Ice Data Center (NSIDC), based at the University of Colorado-Boulder, global mean temperatures have risen slightly more than one degree in the past 100 years, with most of the increase in the last 25 years. NSIDC examined 38 years of NASA satellite photographs on 40 mountain glaciers in Europe, North America and the former Soviet Union to conclude that glaciers are shrinking in most regions of the world. In many areas where alpine ski resorts are the engines of local economies, mountain glaciers anchor the snow pack on which business depends.

Ski resorts across the United States have joined together to lobby for political action on climate change. In 2003, 70 ski resorts backed the Climate Stewardship Act, a federal plan sponsored by Senators John McCain (R-Arizona) and Joe Lieberman (D-Conn.) to fund research on abrupt climate change, set stricter vehicle emission standards and discourage dependence on foreign oil. The plan failed to pass, but since 1999 more than 150 ski resorts have joined the National Ski Area Association’s (NSAA) environmental charter, agreeing to make environmental improvements to their resorts.

Currently, the NSAA is attempting to further a “Keep Winter Cool” program to research global warming. The NSAA’s environmental charter clearly recognizes that “the environment is a ski area’s number one asset.”

Talking about climate change is a delicate matter for those who depend on winter tourism. Despite the overwhelming weight of scientific evidence that ties climate change to human behaviors, some remain skeptical that global warming is man made.

“Generally, I wouldn’t say the weather is changing; it hasn’t affected the ski industry. The ski industry is holding firm,” said Stefanie Dalgar of the Colorado Tourism Office. However, Dalgar said, persistent drought in Colorado has negatively affected ski resorts.

What Colorado Tourism public relations calls “holding firm,” Keith Zimmerman—a spokesman for Travel Michigan—sees as a shift in the Michigan resort economy: depending more on summer golfing revenues to make up for declining winter business.