A new study published in the journal Geophysical Research Letters has revealed that for the past two decades, Yellowstone National Park has been warming at the fastest rate in 1,250 years. Further, the study found that the hottest year in the region in recent times was 2016; the previous warmest year was 770.
The study was conducted by a team of scientists led by Karen Heeter at the University of Idaho in Moscow. The team collected samples of living and fossilized Engelmann spruce trees in northwest Wyoming. Samples were collected from Yellowstone National Park — the oldest national park in the U.S. — and Shoshone National Forest. They used data from tree rings to reconstruct the summer temperatures over hundreds of years.
Tree rings are vital to scientists, because they can be used to provide key information about climate dating back thousands of years. Such data can help determine the type of climates a tree has experienced over its lifetime.
The researchers were able to reconstruct the summer temperatures of Yellowstone National Park with a focus on August, when summer temperatures at the park are the highest. The researchers used a special analysis, known as “blue intensity,” which measures blue light reflected from tree rings. This method helped the scientists measure characteristics of the tree rings, like density, that are closely related to summer temperatures.
The study authors said that their discovery is one of the few tree-ring records dating back over a thousand years in North America. Most other records only date back a few hundred years.
In their quest to learn more about summers in Yellowstone, the researchers found that the park has been through its fair share of periods of considerable cooling and warming over the last millennium. But the period between the years 2000 and 2021 was found to be the most intense in terms of warming.
Other warm periods found occurred in years characterized by large-scale natural disasters. For instance, 1988 was found to be the fourth warmest year in history. In the same year, wildfires swept across the park and burned about 800,000 acres of land. The scientists are now warning that if action is not taken to stop climate change and global warming, the forest will be lost to fires.
Image via David Mark