The glacier has been one of the most photographed glaciers in the park and many of these photographs date back to the mid 19th century. When compared with images taken over subsequent years, the glacier has obviously retreated substantially. This is a pattern repeated throughout the park and worldwide, strong evidence of a global climate change correlating with Global warming. In 1850, at the end of what has been referred to as the Little Ice Age, Grinnell Glacier measured 2.88 km², including the area of The Salamander, an ice apron or shelf glacier that used to be attached to Grinnell, but is now separate. By 1993, Grinnell Glacier measured 0.88 km² and The Salamander measured 0.23 km². Glaciologists that have researched the glaciers in the park have predicted that all the glaciers in the park, including Grinnell, will disappear by the year 2030.
Gem Glacier, the smallest remaining glacier in the park, is located on the Garden Wall above Grinnell. Repeat photography of the glacier taken between the years 1938 and 2005 (as shown below) demonstrate that the glacier has retreated significantly in that period. Interestingly, The Salamander and Gem Glacier have shown little change in area over the same period of time. The Salamander receives its name for its shape and its coloring, which comes from the serratia bacteria that grows on it.
The glacier can be reached after a 6 mile (9.6 km) hike from a trailhead beginning at Swiftcurrent Lake. The trail has an altitude gain of just over 1,600 feet (487 m), with the majority of that in the second half of the hike.