Glaciology

Visualization by NASA showing the retreat of the Smith Glacier grounding line between 1996 and 2011.

Understanding Glacier Grounding Lines

Caitlin Dempsey

Grounding lines are the boundaries where glaciers and ice sheets transition from resting on solid ground to floating on seawater.

This 2024 Landsat 8 image shows Yakutat, Alsek, and Grand Plateau Glaciers have retreated up to 7.8 kilometers (4.8 miles), with lakes filling the void. Over 40 years, the lakes more than doubled in size to 240 square kilometers—larger than New York’s Seneca Lake.

The Rise of Proglacial Lakes

Caitlin Dempsey

Glacial retreat in Alaska's Yakutat Foreland has fueled rapid growth of proglacial lakes, doubling their size in 40 years as seen in Landsat imagery.

Side by side satellite images of a glacier in 1988 and 2015 showing the glacier shrinking.

Venezuela Becomes the First Country to Lose its Glaciers

Caitlin Dempsey

Venezuela became the first country to lose all of its glaciers as the last remaining ice on Pico Humboldt shrank to less than two hectares.

An annotated satellite image of a white icy area.

Understanding Fast Ice in Polar Ecosystems and Climate Dynamics

Caitlin Dempsey

Fast ice, found in both polar regions, is sea ice that attaches to coasts, icebergs, ice shelves, or the ocean floor.

A rocky outcrop of a mountain completely surrounded by glaciers.

Nunataks: Glacial Islands

Caitlin Dempsey

Nunataks are isolated mountain peaks emerging above ice sheets in polar and high-altitude regions.

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