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MMSD To Help Measure Heat Island Effect

08/23/22 02:00:pm

Contact: Bre Plier, MMSD Manager of Sustainability, (414) 225-2079

The number of extremely hot days in Wisconsin is expected to quadruple in the next 30 years. This increase will disproportionately affect neighborhoods with limited resources where residents often do not have adequate air conditioning or energy-efficient housing. Identifying where and how heat is distributed will empower local decision-makers and anchor institutions to allocate resources better to respond to or mitigate the adverse effects of this increased heat. Scientific literature has noted that areas with more green infrastructure, particularly tree cover, are cooler because of evapotranspiration and shade.

This summer, MMSD is working with the Wisconsin Department of Natural Resources (WDNR), Groundwork Milwaukee, the National Oceanic and Atmospheric Administration (NOAA), and CAPA Strategies (CAPA) on a heat mapping study in the City of Milwaukee.

This study will gather and analyze urban heat data to better enable air temperature to be incorporated into prioritization models for planting trees and maintaining green spaces. This work is especially important given the limited resources for implementing green infrastructure projects and preserving open space. These heat data can be leveraged to place trees and other types of green infrastructure where they would do the most good, both socially and environmentally. Identifying heat distribution may also lead to selecting the most appropriate tree species for a given space.

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    Stormwater tree tour in Milwaukee, WI

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    Tree Plantings in Milwaukee, WI

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    Urban Green Space

In addition to better prioritizing greening efforts, it is expected that this data will be used to assist in response to heat events, as they would indicate the areas most in need of intervention within the City of Milwaukee. This could mean the better placement of cooling centers and more focused efforts for energy and thermal efficiency programs.

Finally, this study can help to provide data for modeling and create a greater understanding of how temperature is distributed relative to Lake Michigan and other significant waterbodies in the city. The data from this study, and the maps that will be generated, will be used to inform existing climate science research.  Specifically, this study may be helpful in a joint research project between MMSD and the University of Wisconsin-Madison investigating how strategic greening may reduce the effects of the urban heat island and how micro-climates and storms interact with Lake Michigan.

NOAA Urban Head Island Mapping Campaigns

NOAA and partners have conducted heat island mapping campaigns in 69 communities from 2017 to 2022. (

Over the last few years, dozens of communities across the country have worked with CAPA’s methodology to perform heat measurement analyses under a contract from NOAA. This project is funded by NOAA and has no cost to MMSD. Local partners, such as Groundwork Milwaukee, oversee the actual data collection through instruments attached to cars or bicycles deployed on prearranged routes three times during one of the hottest days of the summer. All the data are then analyzed and extrapolated by CAPA, and city-wide temperature distribution maps are produced. The data are then made publicly available to be used for decision-making and model building.