On April 28, 2025, the National Weather Service placed more than 5 million people under a Level 4 severe thunderstorm risk. Meteorologists warned that the storm, spanning across parts of southern Minnesota, western Wisconsin, and northern Iowa, could result in a life-threatening tornado outbreak. As the storm moved across the Upper Midwest, Green Bay found itself on the edge of a line of tornado watches.
Radar images showed heavy bands of precipitation extending across the region, along with all of the signs of a thunderstorm, such as lightning, thunder, and heavy winds. By nightfall, 7 tornadoes had touched down across Wisconsin, 5 of them concentrated in Eau Claire County and 2 more touching down in Shawano County. No injuries or fatalities were reported, but the storm did not leave without inflicting damage: agricultural buildings (barns, silos, etc.) were torn down, homes were hit with debris, and vehicles were damaged.
This extreme weather event is not an isolated incident. Scientists warn that climate change is fueling more frequent and intense storms across the Midwest, amplifying the risks for areas such as Green Bay.
The Science Behind the Storms
As the Midwest faces increasingly frequent and intense storms, scientists point to climate change as a key factor reshaping weather patterns. Severe storms which are characterized by not just lightning but also heavy rainfall, hail, and powerful winds are becoming more common, with research proving that rising global temperatures and shifting atmospheric conditions play a pivotal role.
“If you think about how the atmosphere interacts with the lakes and the land and as everything is warming up, then [that] changes how much energy and moisture is stored up in the atmosphere and could impact those [severe weather] events,” said Kevin Fermanich, Professor of Geosciences, Natural & Applied Science at University of Wisconsin – Green Bay.
A storm’s formation is dependent on certain meteorological conditions. Atmospheric temperatures are the first factor. Warmer air near the Earth’s surface encourages convection and allows the upward motion necessary for storm development. Climate data confirms that average temperatures are rising, with the United States warming at a faster rate than the global average, particularly since 1970. This temperature increase fuels storm activity by intensifying moisture levels in the air.
Humidity is another crucial component. As global temperatures climb, evaporation rates speed up, leading to greater amounts of water vapor in the atmosphere. This extra moisture contributes to heavier rainfall during storms and worsens flooding risks. Research from the Center for Science Education indicates that hourly rainfall rates have increased by 13% on average, with some regions experiencing surges of up to 40% since 1970.
A report by NOAA outlines the relationship between climate change and extreme weather events. Scientists use observations, climate models, and historical weather data to assess how human activity influences storm intensity. By comparing scenarios with and without human-caused climate shifts, researchers can determine whether events like heat waves, severe thunderstorms, and torrential rainfall are becoming more extreme due to greenhouse gas emissions, aerosol variations, and land-use changes.
According to NOAA, climate scientists are highly confident (>90% probability) that human-induced climate change has increased the frequency of heat-related extreme weather events and intense precipitation across many regions. However, direct human influence on hurricanes and tornadoes remains uncertain, though rising sea levels continue to worsen coastal flooding.
Wisconsin, too, has seen shifts in its climate. “In northeast Wisconsin, for instance,” said Fermanich, “we’re about 20% wetter on average…from 1950 to 2023. Our annual max temperature has gone up 3°, our max winter temperatures have gone up five degrees…the Great Lakes are warming, particularly Superior is warming a little bit more rapidly than Lake Michigan.”
The Wisconsin Initiative on Climate Change Impact also backs these numbers. They created the following graphs based on the recorded everyday temperatures from 1950 to 2023. Wisconsin has also seen an increase in its annual minimum temperature of 5 degrees.
Climate models used to project Wisconsin’s future suggest these trends will persist. Projections indicate a continued rise in temperature between 4°F and 7°F by 2041-2060, with some extreme cases forecasting warming beyond 10°F. Additionally, annual precipitation levels are expected to shift, with most changes ranging between -5% and +10%, creating uncertainty about future weather extremes.
This graph displays projected changes in annual mean temperature (TMEAN) for Wisconsin from 1981-2010 to 2041-2060 under the SSP245 scenario (represents a “middle-of-the-road” future where global development follows historical trends, moderate economic growth, and technological progress). The x-axis represents temperature change in Fahrenheit (°F), ranging from -2°F to 20°F, and the y-axis shows cumulative probability. The curve indicates the probability distribution of temperature changes.
This graph represents projected changes in annual precipitation (PRCP) for Wisconsin from the period 1981-2010 to 2041-2060 under the SSP245 scenario. The x-axis shows the percentage change in precipitation, ranging from -30% to +30%, while the y-axis represents cumulative probability (0 to 1). The curve in the graph displays the distribution of potential changes in precipitation.
When it comes to the topic of climate change, discussions often receive pushback when it comes to using future projection models to warn people of the effects we are seeing on our atmosphere and climate. “All of the predictions are based on data and evidence that they’re able to gather…In the 1990s or early 2000s, the projections are very good [accurate]. What was projected is what’s happening…,” Fermanich said. “You’ve got to have some confidence that based on the understanding of what’s happened in the past and how we understand the human system or the earth system is functioning, we can put some reasonable projections on what’s the likely outcome.”
As Wisconsin experiences wetter, warmer conditions, the scientific consensus remains clear. Climate change is influencing storm severity, posing risks to infrastructure, agriculture, and public safety. The data suggests that storms like the one that struck Eau Claire and Shawano counties in April may be part of a broader trend.
Community Impacts
The impact of extreme weather events goes further than just damaging infrastructure. Farmers struggle to protect their crops, rural communities face heightened risks, and low-income populations experience disproportionate challenges. Climate change is reshaping the way Wisconsinites prepare for and respond to severe weather.
For Wisconsin farmers, shifting weather patterns make it harder to establish a schedule for taking care of their crops and livestock. Heavy rainfall events are becoming more frequent, resulting in washed-away topsoil, disrupted farm operations, and damaged buildings, which makes it harder to maintain productivity. Flooding delays planting in the spring and harvesting in the fall, narrowing the window for a successful yield. Excess water also flushes fertilizers into rivers, affecting both local ecosystems and crop sustainability. Warmer winters mean less ice and snow cover, which impacts crops like cranberries that rely on frozen protection, and higher temperatures allow invasive pests to survive longer or migrate north. Dairy cows, too, suffer under prolonged summer heat waves. Extreme temperatures lead to stressed-out livestock, which reduces milk production. In order to combat droughts, farmers must invest in irrigation systems which can be an extreme financial burden.
Rural communities in Wisconsin also face a host of challenges when it comes to severe weather. The aftermath of these storms can put a heavy strain on the local emergency response teams. A University of Wisconsin-Madison initiative is working to develop resilience strategies, partnering with local officials and farmers to improve disaster preparedness. In Green Bay, extreme heat events are becoming more frequent during summer. Heat waves disproportionately impact low-income communities that have limited access to cooling. The Heat Vulnerability Index pinpoints areas where residents lack air conditioning or live in poorly insulated housing, increasing their risk of heat-related illnesses.
“If you look at all of the types of severe weather that can cause fatalities,” said Steven Meyer, PhD, Associate Professor at UW-Green Bay, “heat is actually the number one killer…by Green Bay Sustainability Commission having plans in place, you need to think of who needs to be involved in those plans.”
Similarly, flooding events make evacuation difficult for residents without reliable transportation, putting them at heightened danger during disasters. Reduced ice cover on Lake Michigan and the Bay of Green Bay has led to unpredictable storm surges. Municipal leaders are working on sustainability plans to address these risks, but solutions require funding and coordinated community efforts.
During an interview with Melvin Johnson, PhD, Green Bay Sustainability Commission and an associate professor of Geography and Geoscience at UW-Manitowoc, he underscored the importance of drills and weather education, stating, “Basic education of the population [is key]. What is your hazard? How best to deal with that hazard? What happens if you get something more than a normal storm?… How to check on your neighbors? You may not be able to minimize physical damage, but you can minimize the loss of human life.”
Johnson also points to disparities in housing structures. He said, “The unfortunate thing with a lot of low-cost housing is that they are oftentimes constructed less than standard, which means that you know that community is going to be impacted more, which is unfortunate.” For those living in mobile homes, knowledge about wind direction, home orientation, and emergency planning can make a significant difference in storm impact.
As Wisconsin communities adapt to increasingly volatile weather, the need for better planning, stronger infrastructure, and coordinated response efforts becomes urgent. Local officials, researchers, and residents must work together to ensure that the most vulnerable populations receive adequate protection.
Policy Responses and Initiatives
Wisconsin is currently taking steps to address the growing threats posed by climate change, with efforts spanning state government policies and local initiatives. The state government has implemented executive orders aimed at reducing carbon emissions and promoting clean energy. Executive Order #38 established the Office of Sustainability and Clean Energy to address the goal of carbon-free electricity by 2050. Executive Order #52 created the Governor’s Task Force on Climate Change, which is tasked with developing climate adaptation and mitigation strategies. In 2022, Wisconsin released its first Clean Energy Plan which focused on prioritizing environmental justice and renewable energy expansion. In 2023, Governor Tony Evers released the Progress Report, which highlighted key advancements made toward the Clean Energy Plan goals, such as $10 million in grants for renewable energy projects, battery storage expansion, and microgrid development.
At the local level, communities across Wisconsin are actively committing to sustainability. More than 148 municipalities have pledged to generate 25% of their energy from local renewable sources by 2025. Several cities have formed sustainability commissions, while mayoral commitments continue driving climate action. Coastal communities are investing in infrastructure designed to combat storm surges, while inland cities focus on disaster preparedness and heat mitigation strategies.
However, mitigation alone is not enough, but it must be paired with efforts to adapt to weather changes. Reports from the Wisconsin Initiative on Climate Change Impacts (WICCI) emphasize the urgency of infrastructure upgrades, flood prevention systems, and comprehensive energy efficiency programs to safeguard Wisconsin’s economic landscape.
Unfortunately, the largest hurdle when it comes to getting climate issues addressed is getting political viewpoints aligned. “Getting the legislature and the executive branch of our state government on the same page in terms of seeing that climate change is a real thing… is almost impossible,” said Johnson.
Despite challenges, Wisconsin’s evolving policy landscape reflects a growing momentum toward climate resilience. With continued investment in clean energy, infrastructure improvements, and collaborative policymaking, the state aims to build a more sustainable future while mitigating the impact of climate change on its residents.