Climate Working Group

Wisconsin’s climate continues to change, and our citizens and businesses are already feeling the impacts. In the decade since WICCI released its 2011 Assessment Report, the WICCI Climate Working Group has continued to advance our understanding of climate change in Wisconsin.

Three Main Findings Have Emerged

New analyses of historical climatic changes over the last 10 years – especially seasonal warming, precipitation changes, and increases in extreme climatic events – are qualitatively consistent with expectations from WICCI’s 2011 Assessment Report.

Additional information from new climate model projections continue to support the conclusions from a decade ago.

New scientific findings and analyses add additional confidence to our previous findings, and they provide new insight on specific climatic impacts that are relevant for Wisconsin.

The Climate Working Group’s analysis for the 2021 WICCI Assessment Report demonstrates that Wisconsin is becoming warmer and wetter.

Major Takeaways

• The past two decades have been Wisconsin’s warmest since accurate statewide records began in the 1890s
• Winters are warming more rapidly than any other season, and nighttime temperatures are rising more than daytime temperatures.
• By mid-century, the number of extremely hot days (90^oF or higher) in Wisconsin is likely to triple, and the frequency of extremely warm nights (low temperature of 70^oF or above) is projected to quadruple.
• The 2010s were Wisconsin’s wettest decade on record by far, and 2019 was our state’s wettest year.
• During the past decade, there were more than 20 daily rainfalls extreme enough to be considered “100 year events”, meaning that they are expected to occur only once per century.
• Wisconsin will likely become wetter in the future, particularly during winter and spring, although we have less confidence in how rainfall amounts will change during summer.
• Extreme precipitation will probably continue to increase in the future, with very extreme rainfalls increasing the most.

Environmental and climate justice has emerged in recent years as an important aspect of climate change, and it needs to be accounted for when considering adaptation strategies. The 2021 WICCI Assessment Report cites various examples of injustice in terms of specific climate change impacts. Regarding climate change itself, some instances include:

Disproportionate Impacts

People who are less responsible for causing climate change due to their smaller individual or collective carbon emissions are often more affected than high polluters by its impacts.

Less Resilience

Even aside from contributions, some people and communities have less resilience to climate change impacts, due to resource disparities rooted in historical injustice.

Negative Health Effects

Underrepresented communities often live in closer proximity to pollution sources that cause climate change through carbon emissions and cause health problems though degraded air quality.