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19.02.2025 17:00

Melting Glaciers Increase Loss of Freshwater Resources and Rise Global Sea Levels

Kurt Bodenmüller Kommunikation
Universität Zürich

    The melting ice from glaciers worldwide is leading to an increased loss of regional freshwater resources. And it is causing global sea levels to rise at ever-greater rates. Since the year 2000, glaciers have been losing 273 billion tons of ice annually, according to estimates by an international research community led by researchers of the University of Zurich.

    Separate from the continental ice sheets in Greenland and Antarctica, glaciers covered an area of 705,221 km2 and contained 121,728 billion tons of ice globally in 2000. Since then, glaciers have lost about 5% of their ice globally, and regionally between 2% on the Antarctic and Subantarctic Islands and 39% in Central Europe. Annually, glaciers lost 273 billion tons – 273,000,000,000,000 kg – of ice, with an increase of 36% from the first (2000−2011) to the second (2012−2023) half of the period. Glacier mass loss is about 18% larger than the loss from the Greenland Ice Sheet and more than twice that from the Antarctic Ice Sheet.

    Worldwide research community effort

    For the new study, an international research team under the coordination of the World Glacier Monitoring Service (WGMS), hosted at the University of Zurich (UZH) in Switzerland, carried out the so-called Glacier Mass Balance Intercomparison Exercise (GlaMBIE). The research community collected, homogenized, combined, and analyzed glacier mass changes from different field and satellite observation methods. The team then compared and combined the results from the different methods into an annual time series of glacier mass changes for all glacier regions in the world from 2000 to 2023.

    The researchers compiled 233 estimates of regional glacier mass changes from about 450 data contributors organized in 35 research teams. “By combining the advantages of the different observation methods, GlaMBIE provides not only new insights into regional trends and year-to-year variability. We could also identify differences among observation methods, which is an opportunity to better understand and improve future estimates,” says Michael Zemp, UZH professor at the Department of Geography, who led the study.

    Sinking regional freshwater resources, rising global sea levels

    From 2000 to 2023, the global glacier mass loss totals 6,542 billion tons. This loss contributed 18 mm to global sea-level rise at an annual rate of 273 billion tons or 0.75 millimeters yearly. With this, glaciers are currently the second-largest contributor to global sea-level rise, after the warming of the ocean and before the contributions from the Greenland Ice Sheet, changes in land water storage, and the Antarctic Ice Sheet.

    In addition, glacier melt results in the loss of regional freshwater resources. “To put this in perspective, the 273 billion tonnes of ice lost in one single year amounts to what the entire global population consumes in 30 years, assuming three litres per person and day,” states Zemp.

    “Glaciers are vital freshwater resources, especially for local communities in Central Asia and Central Andes, where glaciers dominate runoff during warm and dry seasons”, says UZH glaciologist Inés Dussaillant, who was involved in the GlaMBIE analyses. “But when it comes to sea-level rise, the Arctic and Antarctic regions with their much larger glacier areas are the key players. Almost one quarter of the glacier contribution to sea-level rise originates from Alaska,” she adds.

    Limiting negative effects through climate protection

    The present study marks an important milestone for the International Year of Glaciers’ Preservation in 2025 and the Decade of Action for Cryospheric Sciences (2025−2034) declared by the United Nations. GlaMBIE provides a new observational baseline for future studies, allowing improved projections of freshwater resources and sea-level rise.

    “Our observations and recent modelling studies indicate that glacier mass loss will continue and possibly accelerate until the end of this century”, says UZH glaciologist and GlaMBIE project manager Samuel Nussbaumer. “This underpins Intergovernmental Panel on Climate Change’s call for urgent and concrete actions to reduce greenhouse gas emissions and associated warming to limit the impact of glacier wastage on local geohazards, regional freshwater availability, and global sea-level rise”, he concludes.

    Funding
    The European Space Agency (ESA) funded the study with additional support from the International Association for Cryospheric Sciences (IACS) and authors' institutions and projects. It was carried out by the GlaMBIE Team under the lead of the World Glacier Monitoring Service, hosted at the University of Zurich in Switzerland, in collaboration with the University of Edinburgh and Earthwave Ltd, UK, and 35 research teams worldwide.


    Wissenschaftliche Ansprechpartner:

    Prof. Dr. Michael Zemp
    World Glacier Monitoring Service
    Department of Geography
    University of Zurich
    +41 44 635 51 39
    michael.zemp@geo.uzh.ch


    Originalpublikation:

    Michael Zemp et al. (GlaMBIE). Community estimate of global glacier mass changes from 2000 to 2023. Nature. 19 February 2025. DOI: https://doi.org/10.1038/s41586-024-08545-z


    Weitere Informationen:

    https://www.news.uzh.ch/en/articles/media/2025/Glacier-loss.html


    Bilder

    Glaciers in the Chugach Mountains of Alaska. This image, recorded by the Sentinel-2 satellite on 6 October 2017, shows the melting Scott (left), Sheridan (middle), and Childs (right) glaciers feeding lakes and rivers in their forefields.
    Glaciers in the Chugach Mountains of Alaska. This image, recorded by the Sentinel-2 satellite on 6 O ...

    Copernicus Sentinel data 2017

    A fleet of satellites has been used to monitor glaciers worldwide using optical, radar, laser and gravity measurements. From top: CryoSat, Terra, ICESat, and the twin GRACE spacecraft.
    A fleet of satellites has been used to monitor glaciers worldwide using optical, radar, laser and gr ...

    ESA, NASA, and Planetary Visions


    Merkmale dieser Pressemitteilung:
    Journalisten
    Meer / Klima, Umwelt / Ökologie
    überregional
    Forschungsergebnisse, Wissenschaftliche Publikationen
    Englisch


     

    Glaciers in the Chugach Mountains of Alaska. This image, recorded by the Sentinel-2 satellite on 6 October 2017, shows the melting Scott (left), Sheridan (middle), and Childs (right) glaciers feeding lakes and rivers in their forefields.


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    A fleet of satellites has been used to monitor glaciers worldwide using optical, radar, laser and gravity measurements. From top: CryoSat, Terra, ICESat, and the twin GRACE spacecraft.


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