Ann Arbor Times

The University of Michigan has conducted a study revealing that fungal spore seasons in the United States have advanced by three weeks over the past two decades due to climate change. The research, published in GeoHealth, was led by Ruoyu Wu during her master's degree at the U-M School for Environment and Sustainability. Wu, now pursuing a doctoral degree at the University of Florida, stated, “Over the past two decades, fungal spore seasons in the U.S. have shifted significantly due to climate change. This has implications for both ecosystem processes and human health.”

The study analyzed data from 55 pollen counting stations associated with the U.S. National Allergy Bureau between 2003 and 2022. It found that spore allergy season began 22 days earlier in 2022 compared to 2003.

Kai Zhu, senior author of the study and associate professor at U-M, remarked on the significance of these findings: “This is the first time that we’ve been able to show that the fungal spore seasons have changed, and the change is pretty big. That’s three weeks over the past two decades.”

A related epidemiological study from 2023 indicated that approximately one in five clinical samples from over 1.6 million patients showed sensitivity to fungal allergens. The research suggests individuals may need to prepare for allergy season earlier than before.

Yiluan Song, another leader of the study and postdoctoral fellow at Michigan Institute for Data and AI in Society, highlighted additional sources of spores: “We also know that buildings and vegetation are huge sources of fungal spores in the air.” Song emphasized practical measures such as addressing mold issues indoors.

Ecologically, beyond just affecting human health, there is concern about how these changes impact ecosystems. The team observed an ecological shift with spore seasons starting an average of 11 days earlier across the U.S., although overall accumulated spore counts declined during this period.

Song attributed warming temperatures to advancing spore seasons while suggesting drought conditions might be reducing overall spore production: “Here, we see a very visible fingerprint of climate change,” she said.

Collaborators included Jennifer Head from U-M's epidemiology department; Kerby Shedden from statistics; Daniel Katz from Cornell University; and Kabir Peay from Stanford University. The research received support from several institutions including the U.S. National Science Foundation and Department of Energy.