REGIONAL— Northern Minnesota’s timber and tourism industries are expected to be among dozens of economic sectors harmed by ongoing climate change over the next several decades. The loss of cold-water fish species, the decline of boreal tree species, and the resulting impacts on many of the region’s current species of wildlife, are other major risk factors posed by the changing climate.

Those are just some of the many projections and conclusions in a new federal report produced by the U.S. Global Change Research Program, included input and authorship from more than a dozen federal agencies. In broad strokes, the report offered a number of alarming conclusions, including:

Human health and safety, U.S. quality of life, and the rate of economic growth in communities across the U.S. are increasingly vulnerable to the impacts of climate change.  

The cascading impacts of climate change threaten the natural, built and social systems that Americans rely on, both within and beyond the nation’s borders.

Societal efforts to respond to climate change have expanded in the last five years, but not at the scale needed to avoid substantial damages to the economy, environment, and human health over the coming decades.

Without substantial and sustained global efforts to reduce greenhouse gas emissions and regional initiatives to prepare for anticipated changes, climate change is expected to cause growing losses to American infrastructure and property and impede the rate of economic growth over this century.

Closer to home, the impacts cited in the report should be of concern to residents of northern Minnesota. According to the report, the ongoing warming in the Upper Midwest will significantly affect forests, particularly in places like northern Minnesota. “Many tree species— such as paper birch, northern cedar, and quaking aspen, are highly vulnerable to temperature increases,” notes the report. “Populations of the emerald ash borer, a destructive invasive insect pest that attacks native ash trees, will increase due to warming winters in the region. That, in turn, is expected to significantly impact black ash mortality.”

“Warming winters already have economic impacts on the forest industry,” notes the report in its chapter on the Midwest. “In the Upper Midwest, the duration of frozen ground conditions suitable for winter harvest has been shortened by two to three weeks in the past 70 years. The contraction of winter snow cover and frozen ground conditions has increased seasonal restrictions on forest operations in these areas, with resulting economic impacts to both forestry industry and woodland landowners through reduced timber values.”

Declining forests are also expected to impact the tourism sector. “Forest-related recreation such as hunting, fishing, hiking, skiing, camping, wildlife watching, off-highway vehicles, and many other pursuits add to the region’s economy,” stated the report. Citing data from Wisconsin, the report’s authors noted that “forest-based recreationists” spent $2.5 billion annually on such pursuits in Wisconsin in recent years.

Other forest researchers, like University of Minnesota forest ecologist Lee Frelich, have cited projections showing the virtual disappearance of other northern species, like balsam fir, from northeastern Minnesota by the end of the century. And that may not be the worst of it. Frelich notes that the line between prairie and forest could well shift over the next 80 years as much as 300 miles to the north and east, which would put nearly all of Minnesota into the prairie biome.

Warming conditions are also expected to harm cold water fisheries, and impact an industry that attracts hundreds of thousands of visitors to northern Minnesota every year. “For example, in the Midwest region, cool- and cold-water fishes in inland lakes are particularly susceptible to changes in climate because habitat with appropriate temperatures and oxygen concentrations is often limited during summer months,” notes the report. As temperatures warm, these fish experience a squeezing of available habitat during summer months as the water near the lake surface becomes too warm and the dissolved oxygen levels in deeper waters drop below safe levels (see graphic on previous page).

“This “invisible” loss of habitat is driven by increases in water temperatures, longer duration of the stratified period (which delays the mixing of oxygen-rich water into the deeper waters), and declines in ice cover,” notes the report.

Human health

“Climate change is expected to worsen existing health conditions and introduce new health threats by increasing the frequency and intensity of poor air quality days, extreme high temperature events, and heavy rainfalls; extending pollen seasons; and modifying the distribution of disease-carrying pests and insects,” notes the report. “By mid-century, the [Midwest] region is projected to experience substantial, yet avoidable, loss of life, worsened health conditions, and economic impacts estimated in the billions of dollars as a result of these changes. Improved basic health services and increased public health measures—including surveillance and monitoring—can prevent or reduce these impacts.”

At the same time, the report predicts an increase in types of mosquitoes that carry West Nile virus and in the abundance and range of the black-legged tick, which carries Lyme disease.

The report also cited the risks posed by an increasing number of extreme heat days, even in northern Minnesota. The report notes that the highest maximum temperature recorded in northern Minnesota in summer for any five-day period is 88 degrees, the coolest of any place in the Midwest. But as soon as mid-century, that average maximum for the same five-day period is expected to increase to anywhere from 93-95 degrees. In many other parts of the Midwest, that average maximum for a five-day period will rise to more than 100 degrees. That is not only expected to impact human health, due to the effects of extreme heat, but also exceed optimum conditions for the growth of most agricultural crops.

More extreme heat is also expected to worsen air quality in many of the region’s urban areas, as heat tends to elevate levels of pollutants like ozone. In forested regions, like northern Minnesota, air quality may also diminish due to the greater presence of smoke from wildfires during the warmer months.