A major international study has revealed that glacier ice loss is accelerating, significantly impacting both global sea levels and regional freshwater supplies. Conducted by 35 research teams as part of the Glacier Mass Balance Intercomparison Exercise (Glambie), the study found that glaciers have been losing an average of 273 billion tonnes of ice per year since 2000. However, this rate has increased by 36% in the last decade, with glacier ice loss now surpassing the contributions of the Greenland and Antarctic Ice Sheets combined.
Glaciers—excluding the vast ice sheets of Greenland and Antarctica—originally covered 705,221 square kilometers in 2000 and contained around 121,728 billion tonnes of ice. Over the past two decades, approximately 5% of this volume has disappeared, with losses varying significantly by region. Central Europe has seen the most drastic reduction, losing 39% of its glacial ice, while the Antarctic and Subantarctic Islands have lost around 2%. The accelerating rate of glacier ice loss has led to an estimated 18 millimeters of global sea-level rise over the study period.
The Glambie research initiative, coordinated by the World Glacier Monitoring Service (WGMS) at the University of Zurich, worked in collaboration with the University of Edinburgh and Earthwave Ltd. The project compiled and analyzed data from multiple satellite missions, including Terra/ASTER, ICESat-2, GRACE, TanDEM-X, and ESA’s CryoSat, using optical, radar, laser, and gravimetry methods. This extensive dataset allowed researchers to construct an annual record of glacier mass changes globally from 2000 to 2023.
The study confirmed that glaciers are now the second-largest contributor to global sea-level rise, following ocean thermal expansion. They outpace both the Greenland and Antarctic Ice Sheets and changes in land water storage. Notably, nearly one-quarter of the total glacier contribution to rising sea levels comes from Alaska. In addition to rising oceans, the ongoing loss of glacial ice poses a severe threat to regional water security. Many communities in Central Asia and the Central Andes rely on glacier melt for freshwater, particularly during dry seasons. As these glaciers diminish, so do critical water resources for millions of people.
To put the scale of the problem into perspective, the 273 billion tonnes of ice lost annually is equivalent to what the global population consumes in 30 years, assuming three liters of water per person per day. These alarming trends emphasize the urgent need for enhanced climate adaptation and water management strategies.
The research also highlights the importance of continued satellite observations for long-term glacier monitoring. The findings have already influenced the design of future space missions, such as Europe’s Copernicus CRISTAL mission, which builds on ESA’s CryoSat legacy.
By uniting global research efforts and utilizing cutting-edge satellite technology, Glambie has provided an invaluable observational baseline for future studies. Understanding glacier ice loss is critical for mitigating its effects on water availability and sea-level rise. The study underscores the urgent need for action to address the growing consequences of climate change.