The park’s glaciers, however, are in danger of melting away. Take Grinnell Glacier, for instance. It’s the most famous one in the park.

The glacier has melted a lot throughout the years. It is much smaller now than it was in 1938. Water from the glacier has formed a new lake in the park.

At this rate, the once mighty Grinnell Glacier could soon vanish completely. So could the park’s twenty-five other glaciers.

Grinnell Glacier 1938–2006

The red lines show the glacier getting smaller.

1938

1981

1998

2006

U.S. Geological Survey

Turning Up the Heat

Why is Grinnell Glacier wasting away? It’s simple: The park is getting warmer. Since 1910, the average summer temperature there has risen more than three degrees Fahrenheit (F).

The park isn’t the only place that’s warming up. Most scientists agree that the rest of Earth is slowly warming up, too.

The rising surface temperature is called global warming. Since 1850, Earth has warmed by about one degree Fahrenheit. Some places, such as Glacier National Park, have warmed up more, and some have warmed up less.