Animation: A visualization of the Land Ice Portal, credit: CPOM

Since the launch of Earth Observation satellite missions, the information we have on ice on Earth has taken a significant leap forward. We can now monitor Earth’s ice without having to go to the poles, but despite this incredible step forward in technology, it is still challenging for scientists to process and interpret the data we acquire from satellite missions.

CPOM’s new land ice portal provides a renewed and improved public access visualization tool for CPOM’s ice sheet monitoring products.

Currently covering Antarctica, with Greenland due to be added shortly, it monitors mass and surface elevation change of the ice sheets, derived from European radar altimetry missions. The data currently spans 1995 to the present, drawing on three European Space Agency (ESA) missions: ERS-2, Envisat, and CryoSat-2, with NASA’s ICESat-2 used for validation purposes.

Processing raw altimetry data is a complex task that CPOM has been developing expertise in for over 20 years. Creating accessible portals saves users significant time and effort by providing high-level elevation and mass change products needed for their research.

The portal supports:

Ice sheet mass balance & sea-level assessment

Elevation-change data underpins the periodic community mass-balance reconciliation exercises (IMBIE), which combine altimetry, gravimetry, and input-output method estimates into the data used in IPCC assessments.

Model initialisation and validation dynamical ice sheet models

BISICLES (used in the UK Earth System Model) and the ISMIP6 model intercomparison use observed elevation/mass trends as boundary conditions and validation targets for future sea-level projections.

Regional/basin studies of specific dynamic imbalance such as Pine Island, Thwaites grounding-line retreat and key areas of Antarctic research.

The portal is designed with enhanced accessibility for users in mind, and offers a quick, straightforward data download function covering 1995–2026, in multiple formats, including uncertainty estimates.

The portal offers two main modes of visualization:

1. Maps showing surface elevation and mass change across the ice sheets.
2. Time series of change for each glaciological drainage basin.

Antarctica is divided into glaciological basins using established polygon definitions developed by various research groups, including critical areas like Pine Island and Thwaites Glacier in West Antarctica, where the majority of mass loss, and therefore sea level contribution, is occurring. Users can view time series for individual basins, for West/East Antarctica and the Antarctic Peninsula as regions, and for Antarctica as a whole.

What’s New Compared to the Previous Portal?

• Combined mass and elevation change: for the first time, both are available on the same portal (previously only surface elevation change was included). Mass change is particularly important for understanding sea level impacts and deriving it from elevation data involves complex processing.
• CF compliance: products are now fully compliant with the Climate and Forecasting metadata standard, making the data easier to use.
• Cumulative change products: previously only rates of change were provided; now time series of cumulative change is available too, giving users the flexibility to derive their own trends over their period of interest.
• Clickable basin time series: a new interactive feature.
• Cumulative change animations: previously produced in isolated instances, now integrated into a single portal for the first time.

Why Continued Maintenance Matters

Maintaining and improving the portal is an ongoing necessity for several reasons:

1. Contemporary observations: the portal is frequently updated with the latest observations, so users get up-to-date information about the health of the ice sheets.
2. Evolving input data: the space agencies continuously update and revise the raw altimetry data, so the processing pipeline must adapt accordingly.
3. Auxiliary data models: processing relies on auxiliary inputs like firn models (used to account for varying snow density across the ice sheet and how it changes over time), which are also updated regularly and are essential for converting elevation change into mass change.
4. Mission transitions: satellite missions themselves change over time. CryoSat-2 is now well beyond its expected operational lifetime, and its successor, CRISTAL, remains on schedule for launch around 2027. New missions bring different data formats and technologies, requiring updated processing methods.
5. Cross-calibration: time series from different missions must be continuously cross-calibrated to ensure consistency, which is an ongoing process as new missions come online.

A portal for scientists and policymakers

Turning raw altimetry into elevation and mass change requires decades of expertise due to the need for waveform retracking, cross-calibration between missions, firn/SMB corrections, conversion to mass etc., so without a user-facing portal that expertise doesn’t reach most of the community.

Having one standardised, CF-compliant, version-controlled product means results across research groups are comparable and this makes exercises like the Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) possible.

The portal not only supports users with visualized and downloadable data for their region of interest, making it comparable to their own data and helps initialise ice sheet models used for sea level projects, but it is also useful for policymakers, who can immediately see the scale of ice mass loss from Antarctica and its implications for global sea levels, with time series making long terms trends clear.

Global temperatures are projected to continue to break records in the coming years according to the WMO. The impact on the polar regions, and the knock-on effect of sea level rise and changes in global weather patterns remain key questions in environmental science. By delivering up-to-date, robust and accessible information on the changing ice sheets, CPOM’s land ice portal supports scientists and policymakers as they seek to answer these questions and plan for a future in a warming climate.

About this work

This work is part of PRESCIENT (UK Polar Research Expertise for Science and Society), a joint National Capability programme between the British Antarctic Survey (BAS) and the UK Centre for Polar Observation and Modelling (CPOM), which supports strategically important long-term measurements and capabilities across four science areas: Polar and Mountain Climate Data Records; Southern Ocean Biological Observatories; Antarctica’s Contribution to Sea-Level Rise; and Space Weather. It also delivers National Public Good by providing independent scientific advice to government, business, and wider society.

Visit the CPOM Land Ice Portal (UCL-hosted website).

Video Credit: ESA/NASA IMBIE Initiative. Sea level contribution data from IMBIE; Ice sheet elevation change from satellite altimetry (Centre for Polar Observation and Modelling). In collaboration with Northumbria University, University Grenoble Alpes, TUD Dresden University of Technology, Jet Propulsion Laboratory, University of Washington APL, University at Buffalo University of Liverpool, University of California Irvine, Technical University of Denmark, NOAA Geophysical Fluid Dynamics Laboratory, Canadian Geodetic Survey, Utrecht University, Université Paris-Saclay, Delft University of Technology, European Space Agency, University of Liège, University College London, Bjerknes Centre for Climate Research, University of Edinburgh, Danish Meteorological Institute, University of Arizona, Alfred Wegener Institute, Aarhus University, NASA Goddard Space Flight Center, Lancaster University, Istituto Nazionale di Geofisica e Vulcanologia, isardSAT, University of Texas at Austin, Seoul National University, University of Bologna, Indian Institute of Science, WSL Institute for Snow and Avalanche Research SLF.

The longest satellite record ever assembled shows that Greenland and Antarctica have lost 11.3 trillion tonnes of ice since the 1970s, raising global sea levels by more than 3 centimetres – and that most of the loss has come from glaciers flowing faster into the ocean, not from melting at the surface.

An international team of polar scientists has produced the most complete picture of ice loss from Greenland and Antarctica to date. The Ice Sheet Mass Balance Inter-comparison Exercise (IMBIE) Team combined 42 independent satellite surveys, drawing on 27 satellite missions and reaching back to 1972 for Greenland and 1979 for Antarctica using the early Landsat archive.

The findings show the two ice sheets lost 11,309 billion tonnes of ice between 1979 and 2023, pushing global sea levels up by 31.4 millimetres. Greenland accounts for the larger share and Antarctica contributed 13.3 millimetres. Strikingly, 84% of the combined loss was driven by glaciers speeding up and pouring more ice into the ocean, with just 16% due to surface melting.

The polar ice sheets are now responsible for around a quarter of all global sea level rise.

The assessment was led by CPOM Co-Director of Science, Dr Inès Otosaka., Northumbria University, and CPOM Director Professor Andrew Shepherd, Northumbria University, and Dr Tyler Sutterley of the University of Washington Applied Physics Laboratory. It is supported by the European Space Agency (ESA) and the US National Aeronautics and Space Administration (NASA) and is published in the journal Scientific Data.

Dr Inès Otosaka, who led the study, said:

“By reaching back to the 1970s, we can now see how the ice sheets have changed across half a century. More than four-fifths of the ice lost was discharged into the ocean by faster-flowing glaciers, rather than melted at the surface – which tells us the long-term trend is being driven by the dynamic response of the ice sheets to a warming ocean.”

The record shows ice losses climbing steeply from the 1990s onwards. Greenland, close to balance in the 1970s, saw its rate of loss rise from around 60 billion tonnes a year in the 1980s to 264 billion in the 2010s, a decade marked by repeated extreme summer melt events. Antarctica’s rate rose from around 48 billion tonnes a year in the 1980s to 202 billion in the 2010s, with all of its net loss caused by ocean melting of its outlet glaciers; West Antarctica’s ice discharge, led by Pine Island and Thwaites glaciers, has risen in every decade of the record.

The most recent years (2020–2023) brought a temporary slowdown in ice loss. Record snowfall over East Antarctica have offset some of the continent’s glacier losses elsewhere, while a run of milder Greenland summers roughly halved its surface melting. Scientists caution these are short-term fluctuations against a clear long-term trend, not a reversal of ice loss.

The findings also underline the ice sheets’ central role in future sea level rise. Their response to a warming climate is the single largest source of uncertainty in sea level projections: high-end estimates of global sea level rise by 2150 increase by a factor of 2.6 once the risk of ice-sheet instability is accounted for. A continuous, half-century record of how the ice sheets are behaving is therefore vital to anticipating the risks facing the hundreds of millions of people who live in low-lying coastal areas.

Professor Andrew Shepherd, Head of the School of Geography and Natural Science at Northumbria University and founder of IMBIE, said:

“Three centimetres of sea level rise may sound small, but that puts another six to nine million people at risk of coastal flooding and erosion. With the ice sheets set to lose much more ice in the decades ahead, global assessments like IMBIE are vital to protecting communities impacted by climate change.”

Dr Tyler Sutterley, IMBIE co-lead, said:

“The added length of the record, the larger pool of participating teams and our improved ability to assess uncertainties make this the most robust assessment of ice sheet mass balance produced so far. Satellites give us continent-wide, year-on-year evidence of what is happening now, and that is exactly what we need to test models and narrow the uncertainties in projections of future sea level rise.”

Dr Diego Fernández, Head of the Science Section at ESA, said:

“These findings show the fundamental importance of using satellites to monitor the ice sheets and to evaluate the models used to predict the effects of climate change. Sustaining missions such as CryoSat-2 and the Sentinels, and maintaining the long-term ice-sheet climate data record, is critical for the decades ahead.”

Further information

• Read the research in Scientific Data.
• Read the Northumbria University news article.
• Read the ESA.int article about this research.
• Visit the IMBIE website.

Image credits: Professor Andrew Shepherd, Professor Alison Banwell and Dr Sammie Buzzard (Northumbria University).