University of Arizona study links tree rings to climate extremes

TUCSON, Ariz. (KVOA) — A new study from the University of Arizona reveals how historical tree-ring data can help predict extreme summer weather events. Researchers, led by Ellie Broadman, analyzed tree rings to understand locked jet stream wave patterns, often preceded by La Niña winters, which can result in severe weather impacting agriculture and public health.

“These types of patterns are particularly impactful, especially when they occur in major crop-growing regions,” Broadman said.

The study, published in AGU Advances, presents the first-ever reconstruction of historical jet stream patterns over the last 1,000 years. By using tree-ring data, researchers identified drought patterns correlating with locked wave5 jet stream behavior.

“We don’t have direct observational data on the jet stream back more than a few decades, so we’re using tree rings as a new way to look at what the jet stream was doing in the past,” Broadman said.

The findings suggest that La Niña winters often lead to locked wave5 patterns in summer, offering a valuable tool for forecasting extreme weather. This research could enhance early warning systems, helping communities prepare for potential climate extremes.

“Modern instruments only cover the same period humans have been warming the planet, so you need the long-term view to really understand the impacts of modern climate change,” Broadman said.

While the frequency of these patterns hasn’t increased, their impacts may intensify due to global warming, posing greater risks for the future.