How might climate change affect Wisconsin?

In the land of the Frozen Tundra, the beauty that comes with fresh winter snow is as anticipated as fresh maple syrup in the fall, glorious wildflower displays in the spring, and the shimmer of a clear blue lake in the summertime. However, the timing of seasonal events that Wisconsinites have come to expect is altering with climate change.

Average temperatures across the state have already begun to increase due to climate change. Since 1950, the average annual temperature has increased by 1.1 degree F. That may not sound like much, but even that small change has led to lakes that are frozen fewer days of the year (Lake Mendota is frozen for nearly a week less today than in the 1950's) and plants that bloom earlier (Compass plants now bloom on average three weeks earlier). Records also show that average winter and spring temperatures have warmed while average summer and fall temperatures have cooled. And unfortunately, average temperatures are predicted to rise between 4-7 degrees F in Wisconsin over the next 40 years.

Now let's add in precipitation. Climate change affects that too. It turns out that climate change is bringing with it more variable and severe precipitation events. For example, winters are actually receiving more precipitation than in the past, but with temperatures warming up, it is likely that this precipitation will fall less often as snow and more often as freezing rain. That's bad news for snow sport enthusiasts like skiers and snowmobilers. On the flip side, summers are receiving less precipitation than before and when it does rain, it is often much harder and more severe than before. As you can imagine, harder and less frequent rainfall leads to more severe erosion, crop stress, and other problems for Wisconsin farmers.

Average Temperature PlotHuman health issues are also of concern with climate change. Pollen levels are predicted to increase, along with ground-level ozone and smog. Increases of these pollutants are anticipated to worsen the effects of allergies and respiratory ailments such as asthma. Extreme heat will continue to create challenges as well. Since 1982, extreme heat has led to the deaths of more people in WI than all other natural disasters combined. The elderly are especially at risk from high heat because they are less able to dissipate heat than young people.

Combinations of changing temperatures and precipitation patterns will also influence native ecosystems. Research at the University of Wisconsin-Madison predicts, for example, that the range of the sugar maple tree will shift further north in the future (The maple syruping season is also likely to begin earlier and end earlier in the year). Research also predicts that trees such as red pine, balsam fir, and paper birch may fail to complete their reproductive cycles in some areas, eventually leading to localized extinctions of these species. In more northern regions of Wisconsin, animals such as the American marten, spruce grouse, and snowshoe hare may shift their ranges as well, perhaps pushing them out of the state entirely.

Lakes and streams will also experience negative impacts due to changing climates. As any fisherman knows, fish and aquatic insects are temperature sensitive and the assembly of fish found in local lakes and streams will change as their water temperatures heat up. Cold water species, like trout, may not fare as well with this change as warm water species. Water levels are likely to lower in the Great Lakes inland lakes, and wetland as increased temperatures lead to increased evaporation.

What does this mean for the Trempealeau NWR?

Trempealeau Visitors

The Trempealeau National Wildlife Refuge lies along the Mississippi River flyway and provides excellent habitat for waterfowl, songbirds, beaver, muskrat, white-tailed deer and more. It is also valuable in that it contains sand prairie, backwater marsh, and hardwood forest habitats. As plant and animal ranges shift with changing climates, managers may need to alter how they manage Refuge resources in the future.


Photo: Visitors at Trempeleau National Wildlife Refuge; Courtesy of USFWS

Video courtesy of Climate Wisconsin,

Wisconsin's Changing Climate: Impacts and Adaptation. 2011. Wisconsin Initiative on Climate Change Impacts. Nelson Institute for Environmental Studies, University of Wisconsin-Madison and the Wisconsin Department of Natural Resources, Madison, Wisconsin.

Climate Wisconsin. 2011. Wisconsin Educational Communications Board.

The Weather Channel. Average Weather for Trempealeau, WI- Temperature and Precipitation. The Weather Channel Website. Retrieved 8/29/2010.