Urban heat islands compound economic impact of climate change


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A 2011 heatwave in New York City produces an orange sunset. (Chris Goldberg/flickr)
Jenna Ladd | May 30, 2017

A recent study published in Nature Climate Change revealed that the climate change is likely to be twice as costly in cities than in rural areas.

An international group of economists found that the world’s largest cities could see temperature spikes of 46 degrees Fahrenheit by 2100 if greenhouse gases continue to rise at the current rate. The top 25% largest cities could are likely to see temperatures rise by about 45 degrees Fahrenheit in the same period of time.

The report explains that about 41 degrees Fahrenheit of warming can be explained by global climate change, but the additional four to five degrees of warming will be the result of the urban heat island effect. Urban heat islands are formed when naturally cooling surfaces like vegetation and bodies of water are replaced by surfaces that trap heat like concrete and asphalt.

Based on their analysis of 1,692 cities, the economists expect the combined heating affect to have negative economic consequences for urban areas. Higher temperatures cause workers to be less productive, raise cooling costs for buildings, and deteriorate water and air quality.

On average, the global gross domestic product (GDP) is expected to drop by 5.6 percent by 2100 due to climate change. In contrast, the most-impacted cities are expected to lose 10.9 percent of their GDP. The researchers provided cost-benefit analyses of several cooling measures in the report, including cooling pavements, green roofs and the reintroduction of vegetation in urban areas. For example, transforming 20 percent of a city’s pavement and rooftops to cooling surfaces could save a city up to 12 times what the structures cost to maintain and install, providing a bump to the local GDP.

The researchers conclude that local efforts to mitigate the effects of climate change can play an important role in global efforts. One of the study’s authors, Professor Richard S.J. Tol, Professor of Economics at the University of Sussex, said, “Any hard-won victories over climate change on a global scale could be wiped out by the effects of uncontrolled urban heat islands.” Tol added, “It is clear that we have until now underestimated the dramatic impact that local policies could make in reducing urban warming.”

ISU researchers develop decision-making tool for sustainable cities


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The city of Des Moines is involved in ISU’s “Big Data for Sustainable City Decision-Making” research project. (Jason Mrachina/Flickr)
Jenna Ladd | October 28, 2016

Researchers at Iowa State University (ISU) and the city of Des Moines are working together to develop a decision-making tool that could revolutionize the way cities tackle climate change and social issues.

Ulrike Passe, associate professor of architecture and director of ISU’s Center for Building Energy Research, is the lead faculty researcher. Passe said, “There’s so much unrelated data available — from census and economic information to policy studies and weather records — but it needs to be merged into a useable model.” Passe added that city planners and officials need to have “a data-based tool that helps them decide how to allocate resources for conservation measures like tree planting and storm water management.”

Passe’s team of 16 researchers from over a dozen disciplines is working closely with Scott Sanders, Des Moines city manager. Sanders said, “The creation of this this decision-making system will provide staff access to an amalgamation of big data, which they presently have no way to effectively evaluate, that is a critical component to the future of successful and resilient cities.” Sanders noted that citywide interest in sustainability is on the rise, he said, “The demand far outweighs the city’s ability to provide all of the required and desired improvements within its current budget constraints. The need for a data-driven process and policy to help assess and prioritize the city’s investments has never been higher.”

The project is focusing its efforts on communities in east Des Moines such as Capitol East, Capitol Park and MLK Jr. Park. Linda Shenk, associate professor of English at ISU, is also involved in the study. She said, “We focus on marginalized populations because they are the most vulnerable to the effects of climate change due to limited resources, yet the most difficult for cities to reach and engage in data collection.” For her part, Shenk has been discussing climate change and brainstorming local solutions with neighborhood groups and high school students. Meanwhile, other researchers in the neighborhoods are gathering data about how citizens interact with their city, communities, and homes using computational thermal-physical models.

Other ongoing projects include a tree inventory in the Capital East neighborhood and energy efficiency research through controlled experiments at ISU’s net-zero energy Interlock house located at Honey Creek Resort State Park. The study’s goal for this year is to compile data about human behavior related to energy use. Moving forward, Passe said, “Our objective is to create decision-making support systems that will help cities and their residents translate this research into actions — new policies, incentives for individual behaviors and community resilience.”

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The above graphic outlines the four phases of the research project along with the 16 ISU faculty that are involved. (Iowa State University)

On the Radio: New Iowa City recycling center takes green construction to new levels


Photo by Dan LaMee, Flickr.

Listen to our latest radio segment here.  It features the efforts of our latest sustainable community – Iowa City.  You can also read the transcript below.

With considerable attention to details including the use of waterless urinals, a new Iowa City recycling center hopes to become the city’s greenest building. Continue reading

On the Radio: Le Mars sets recycling standard for Iowa


Photo by Jimmy Emerson, Flickr

Check out this week’s radio segment here.  It features the efforts of our latest sustainable city – Le Mars. 

After a staggering increase in recycling Le Mars now stands as a model for Iowa’s towns. Continue reading