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Simplified model enhances understanding of long-term glacier behavior and climate change implications

University of Idaho researchers have developed a mathematical model that simplifies the way scientists understand changes in glacier movement. This new approach demonstrates that diverse patterns of ice flow—ranging from short-term fluctuations to multi-year trends—can be explained using a single set of fundamental equations.

The study, recently in Geophysical Research Letters, could help refine climate change predictions and improve our understanding of glacial dynamics. Doctoral candidate Yoram Terleth led the study under the direction of Tim Bartholomaus, associate professor in the Department of Earth and Spatial Sciences.

Glaciers and ice sheets shape the global climate by influencing sea level rise and water cycles, though there is remaining uncertainty around the exact magnitude of future sea level rise resulting from the total volume of ice that will calve, or break off, into the oceans. Traditionally, scientists have relied on complex models to analyze the forces driving glacial movement.

This new model follows a simplified approach that gets to the heart of glacier changes and expands an existing framework to account for a broad range of changes in ice speed. Faster ice speeds generally result in more glacier mass loss, which means more sea level rise.

"Our model shows that short-term and long-term variations in glacier speed can be understood through the same fundamental mechanisms," Terleth said. "Previously, these changes were thought to be driven by separate processes, requiring different models for different timescales."

Recent efforts to model multi-year cycles of fast glacier flow, known as glacier surges, suggest that a gradual build-up of heat or water at the base of glaciers could drive ice flow instabilities. However, past models did not account for seasonal variations in water flux through glaciers and their influence on glacier flow.

This study finds that more porous glaciers could be less likely to surge, while glaciers with a poorly connected drainage system at their base might be more likely to surge. Understanding these processes can help scientists predict long-term changes in ice sheets, such as those in Greenland and Antarctica, which directly impact global sea levels.

Beyond theoretical advancements, this research has practical implications for field studies and future climate predictions. The current model's concepts are applicable to all glaciers and can serve as a foundation for refining more detailed simulations.

Bartholomaus emphasized that their work is not about replicating one glacier's behavior but rather about establishing a broader set of principles that apply across many different ice formations worldwide.

"This model provides a fundamental understanding of how glaciers move," he said. "By identifying universal patterns, we can improve larger, more complex models used for predicting long-term glacier evolution and its impact on global sea levels."

Moving forward, the team plans to expand their research by incorporating additional data sources, including satellite observations and on-site measurements. This will allow them to further validate their findings and refine their predictive capabilities.