A century from now, Minnesota’s climate will likely look very different from the way it does today. However, many of the trends that will drive this change have already been observed over the past few decades.
Temperature: Warmer temperatures are one of the key factors. Average summer and winter temperatures are expected to rise substantially, but the change in winter temperatures will be more dramatic (Global Climate Change Impacts: Midwest, 2009). This leads to a number of problems including:
- Reduced ice cover on Lake Superior, which could cause more evaporation in winter, leading to lower lake levels.
- Also, warmer temperatures, while increasing the length of the growing season, would also make survival easier for native and non-native insects (such as ticks). Increased populations of such insects could threaten plants and animals, as well as human health.
- Heat waves will likely become more common throughout the state, and some species, especially in the north, will have trouble adapting to extreme heat.
Below: Lake Superior ice cover since 1960.
Precipitation: The change expected in Minnesota’s precipitation patterns is complex, but worrisome. Increased precipitation is projected for winter and spring, while in summer higher temperatures will likely lower precipitation. Overall, the state may receive slightly more precipitation than it currently does, but when and how that precipitation comes will be different (Global Climate Change Impacts: Midwest, 2009). Some reasons why this is problematic:
- Spring rains are likely to increase and come more often in the form of heavy downpours, which could lead to substantial flooding.
- Higher summer temperatures and increased evaporation may cause summer rainfall events to be scarcer, which could lead to droughts. Furthermore, the combination of higher temperatures and more scattered precipitation in summer would make conditions for fires more favorable, especially in the northern forests.
- Different parts of the state will see both increases and decreases in snowfall during the winter. In the south, there will probably be less snow, while in the north there could be more.
Climatologists are using a number of different climate models to predict the changes that may occur in the next century. Each model uses different parameters and assumptions, so no one model should be assumed to be accurate. However, most models that account for a continued rise in greenhouse gas emissions predict something along the lines of a 7-11 degree increase in Minnesota’s mean annual temperature. Extreme heat will be more common, as extreme cold becomes less common. Some models expect the majority of the temperature increase to come in the winter, but so far that is only speculation based on a trend over the last few decades. Winter and early spring precipitation could increase by 15-35%, while summer precipitation may decrease as much as 15%. For an interesting look at what Minnesota's climate might look like in the next cenutry according to one climate model, go to: http://www.ucsusa.org/greatlakes/winmigrating/glwinmig_mn.html.
While specific climate projections for northern Minnesota are not easy to find, a recent study on Wisconsin’s changing climate can shed some light on Minnesota’s climate as well. The figure shows that Wisconsin’s winters are projected to get warmer, especially in the northwestern part of the state. Northern Minnesota will probably experience a similar warming.
Copyright 2009 University of Wisconsin Madison, used with permission.