A new study published in the journal Nature Communications reports higher projections of extreme urban heat waves than previously predicted. Urban heat waves (UHWs) can be extremely dangerous, resulting in human deaths and triggering wildfires. With our recent near-annual global tradition of breaking heat records, understanding UHWs is more crucial than ever. The study was published under the title "Large model structural uncertainty in global projections of urban heat waves" from researchers at the University of Illinois Urbana-Champaign Civil and Environmental Engineering (CEE) and the National Center for Atmospheric Research.
Study authors Lei Zhao, Zhonghua Zheng, and Keith W. Oleson developed an urban climate model that provides urban-specific climate signals. Despite that over half of the global population resides in cities, climate models typically do not consider urban areas because their collective land masses account for only 2-3 percent of the earth's land. This model aims to close that gap.
The model the team has developed includes multi-model projections of four high-stakes regions: the Great Lakes region, southern Europe, central India and north China. They showed that their multi-model projections predict a higher probability of risk than a single-model approach - demonstrating how necessary multi-model projections are for accuracy.
For instance, using only traditional models, the Great Lakes region was expected to experience an extreme heat event only once in 10,000 years; yet with the researchers' multi-modeling approach, UHW events could be expected once every four years.
"This work highlights the critical importance of having multi-model projections to accurately estimate the likelihood of extreme events that will occur in the future under climate change," Zhao concluded.
The researchers say that more accurate models will help cities prepare for emergencies with safety guidelines for their residents; without accurate models, cities could drastically misjudge their risk, ultimately putting the health and safety of their citizens at risk.