USGS Repeat Photography Project Documents Retreating Glaciers in Glacier National Park
Global Climate Change Background
Glacier National Park’s namesake glaciers have receded rapidly since the Park’s establishment in 1910, primarily due to long-term changes in regional and global climate. In the last century, the five warmest years have occurred in the last 8 years - in this order: 2005, 1998, 2002, 2003, 2004 (NASA). These changes include warming, particularly of daily minimum temperatures, and persistent droughts. This warming is ongoing and the loss of the Park’s glaciers continues, with the park’s glaciers predicted to disappear by 2030.
Repeat Photography Project Overview
Climate change research in Glacier National Park, Montana entails many methods of documenting the landscape change, including the decline of the park’s namesake glaciers. While less quantitative than other high-tech methods of recording glacial mass, depth, and rate of retreat, repeat photography has become a valuable tool for communicating effects of global warming. With evidence of worldwide glacial recession and modeled predictions that all of the park’s glaciers will melt by the year 2030, USGS scientists have begun the task of documenting glacial decline through photography. The striking images created by pairing historic images with contemporary photos has given “global warming” a face and made “climate change” a relevant issue to viewers. The images are an effective visual means to help viewers understand that climate change contributes to the dynamic landscape changes so evident in Glacier National Park.
The Repeat Photography Project began in 1997 with a systematic search of the archives at Glacier National Park. We began searching for historic photographs of glaciers in the vast collection that spans over a century. Many high quality photographs exist from the parks’ early photographers such as Morton Elrod, T.J. Hileman, Ted Marble, F.E. Matthes, and others who scoured the park to publicize it’s beauty and earn their livings. Copies of the historic photos were taken in the field to help determine the exact location of the original photograph. Photographing the glaciers cannot occur until the previous winter’s snow has melted on the glacial ice and when air quality conditions are considered at least good. This creates a narrow window in the northern clime of Glacier National Park where smoke from forest fires prevented photography on many occasions in the past few years.
Since 1997 over sixty photographs have been repeated of seventeen different glaciers. Thirteen of those glaciers have shown marked recession and some of the more intensely studied glaciers have proved to be just 1/3 of their estimated maximum size that occurred at the end of the Little Ice Age (circa 1850). In fact, only 26 named glaciers presently exist of the 150 glaciers present in 1850.
Glacial recession is one of the most obvious ecosystem responses to the warming climate in Glacier National Park. A collection of these telling repeat photographs can be viewed and the images can be downloaded at various resolutions by visiting the USGS Repeat Photography Website.
In addition to repeat photography, USGS scientists are using quantitative methods to monitor several glaciers to determine the causes of changes, assess their ecological and hydrological effects, and predict future changes and effects. These efforts, combined with repeat photography, enable scientists to further understand ecosystem responses to climate variability in mountain ecosystems.
Daniel Fagre, USGS Research Ecologist
West Glacier, MT