Chapter 1: The Quest to Monitor Glacier Speed

In a groundbreaking effort, researchers are exploring advanced technologies to accurately track the movement of glaciers. Picture a low-altitude aircraft flying over Greenland, equipped with a sophisticated laser system that captures real-time data on glacier velocity. This innovative approach could provide crucial insights into the melting of the Greenland ice cap, which is of paramount importance given projections from the Intergovernmental Panel on Climate Change (IPCC). Their latest report suggests that by 2100, rising sea levels could increase by as much as one meter, endangering millions living in coastal regions.

As glaciers typically advance at a snail's pace—often just two to three kilometers annually—the challenge lies in capturing these slow movements efficiently. Notably, Greenland's Jakobshavn Glacier, the fastest in the region, moves at a leisurely pace of approximately 16 kilometers per year, translating to about 180 centimeters each hour.

Currently, scientists lack an effective method for measuring these gradual velocities in a single observation. Existing techniques involve taking two measurements at different times, where researchers compare the glacier's position over time. Historically, this was done by placing markers at the glacier's edge and returning later to assess movement. Presently, radar-equipped planes can measure glacier fronts but still require follow-up flights for accurate speed assessment. Twila Moon, an ice scientist at the University of Colorado Boulder, often relies on satellite imagery, which also necessitates multiple passes and can be hindered by cloud cover.

Section 1.1: The Limitations of Current Methods

Moon emphasizes the drawbacks of current tracking techniques, stating, “Understanding ice sheet velocity is critical because the velocity is a key variable for understanding how much ice we are losing.” The irregular nature of glacier movement further complicates accurate tracking.

Subsection 1.1.1: A Solution from the World of Light

To address these challenges, physicist Umberto Bortolozzo from the University of Nice Sophia Antipolis and his team are turning to light to gauge glacier speeds. They leverage the Doppler Effect—similar to how radar guns measure vehicle speed—to develop a new method that can detect incredibly slow movements.

The team splits a laser beam, directing one part at a glacier. As it reflects back, the speed-induced color shift becomes measurable when combined with another beam in a specialized liquid crystal. This innovative setup allows them to detect movements as slight as 20 femtometers per second, a resolution more than sufficient for glaciers that typically move mere millionths of a meter each second.

Chapter 2: The Importance of Accurate Measurements

Researchers eagerly anticipate the development of instruments based on this technology. Moon expresses optimism, stating, “If they can create an instrument that works like that and I can put it on the plane or an unmanned flying vehicle or a satellite, that would be great for our field.” Such advancements could significantly reduce uncertainties regarding future sea-level rise and the speed at which it occurs.

The first video, "How Do Glaciers Move? TIMELAPSE! | Earth Science," explores the movement of glaciers through time-lapse visuals, helping to illustrate their slow but impactful dynamics.

The second video, "How To Travel on a Glacier with Xavier De Le Rue | How To Xv," provides insights into glacier navigation techniques, showcasing the unique challenges and beauty of glacial environments.

Matthew Francis is a physicist, science writer, speaker, and educator.

Originally published at Nautilus on March 12, 2015.