Yellowstone National Park is home to a magnificent geyser known as Old Faithful that spits out boiling hot water at regular intervals (on average, every 90 to 94 minutes). I’ve never seen it in person, but I figured there was no rush since with a name like Old Faithful, it’d probably be around forever. Turns out I was wrong, because like pretty much everything else, the geyser is getting screwed up by the climate crisis.
A new study published in Geophysical Research Letters this week found evidence that eight centuries ago, Old Faithful stopped erupting for a several-decade period when the West went through a severe drought. Now climate change is raising the risk of a serious drought across the West, which could once again stop the geyser.
The researchers became interested in Old Faithful’s patterns when they read that other scientists had found pieces of petrified wood on its mound. Those pieces suggested that the now-barren area once fostered tree growth, and since trees could never withstand the heat and alkalinity of the geyser’s regular deluges, that meant something major had changed.
To learn more, the new study’s team obtained 13 chunks of petrified lodgepole pine wood from the site. Then, they used radiocarbon dating—a method used to determine organic material’s age based on a carbon isotope—to learn how old the wood pieces were. They were able to date them back to having grown between 1233 and 1362.
By examining data from nearby tree rings and poring over scientific literature, the authors learned that at that time, the area had seen “severe multidecadal regional droughts.” It was an era called the Medieval Warm Period, when the northern hemisphere saw warm, dry conditions, likely because of changes in ocean circulation.
The study suggests that the long, dry period would have cut off Old Faithful’s water supply. After all, geysers form when there’s an abundance of groundwater that can escape through cracks in the Earth. With no water to burst out, the eruptions came to a halt.
That dry past could look similar to our climate future. According to the National Park Service, Yellowstone is expected to be much hotter and drier by the latter part of the 21st century. If carbon pollution rises dramatically in the coming decades, projections show Yellowstone will be up to 13 degrees Fahrenheit (7.2 degrees Celsius) hotter than it is today. In fact, over the last several decades, researchers have observed that the time between Old Faithful’s eruptions has increased from some 66 minutes in the 1960s to more than 90 minutes today. So unless we’re going to do all we can to curb the climate crisis (which, by the way, we should if we want to survive), we can expect the hot spring to peter out once again.