Mount Rainier may be shrinking due to climate change: Study

Mount Rainer, the active stratovolcano located in Washington state, is likely shrinking due to climate change, according to new research. The loss of snow and ice is one of the most visible signs of human-amplified climate change in mountainous regions worldwide. In the contiguous United States, five locations have maintained year-round frozen peaks over the past century -- all of them in Washington state. However, rising global temperatures in recent decades are threatening to change that, not only by accelerating ice decline, but also by altering the elevations of major mountains, including the popular hiking and tourist destination Mount Rainier. Since the mid-20th century, the summit of Mount Rainier has likely declined more than 20 feet due to snow and ice melt, according to research recently published in the journal Arctic, Antarctic and Alpine Research (AAAR). This decline would also shift the summit location by 400 feet to the south. The U.S. Geological Survey (USGS) determines official elevation changes. Researchers used satellite data, laser measurements and historical photographs to track how the five ice-capped summits have changed since the 1950s, employing new measurement techniques that offer unprecedented accuracy. "Measurements taken on site used base stations around the state to correct the data. So, it gets the number down to the nearest inch," Eric Gilbertson, associate teaching professor at Seattle University and co-author of the study, said in a statement released with the study. Four of the five summits lost 20 feet or more in elevation due to snow and ice loss since the mid-20th century, with the most significant changes occurring in just the past 30 years, researchers said. The shifts are driven not only by warming temperatures, but also by more precipitation falling as rain rather than snow. "The average air temperature on these summits is significantly higher than it was in the 1950s, almost 5.5 degrees Fahrenheit," Gilbertson said in the release. The impacts of climate change extend far beyond shifts in elevation. Mount Rainier, the most glaciated peak in the contiguous United States, has an ice-capped summit and glaciers that feed the headwaters of five major Pacific Northwest watersheds. These glaciers provide essential water for rivers, supplying drinking water downstream, maintaining cold-water habitats for salmon and supporting hydropower generation in the region, according to the National Park Service. Studying these impacts is challenging because there are currently no comprehensive databases, historical or contemporary, that track ice-capped summits. Researchers emphasize the need to expand resources for monitoring this fragile ecosystem, including resurveying mountaintops and integrating the results into maps, mountaineering information and other relevant infrastructure.