The European State of the Climate 2024 report, an annual report compiled by the Copernicus Climate Change Service (C3S) and the World Meteorological Organization (WMO) and implemented by ECMWF on behalf of the European Commission, has been released today, showing Europe to be the fastest-warming continent in what was the hottest year on record for Europe.
This year, the UK Centre for Polar Observation and Modelling (CPOM) contributed to the section on Trends in climate indicators.
The polar ice sheets, in Greenland and Antarctica, store a significant proportion of the Earth’s freshwater. When they melt, they contribute this freshwater to the oceans, not only increasing sea levels, but also affecting ocean circulation. Estimates of the Antarctic and Greenland Ice Sheets mass balance produced by IMBIE, an international collaboration of polar scientists led by CPOM and supported by the space agencies ESA and NASA, are used in this report’s key climate indicator on Ice Sheets.
Since the 1970s, there has been a recorded ice loss of:
Greenland ice sheet: 6776 km3
Antarctic ice sheet: 5253 km3
Please see Figure 19.3 on page 89 of the report.
This report also includes an overview of the different components of The cryosphere, including glaciers, sea ice, and ice sheets and how they interact with each other and the Earth’s wider environment, impacting the climate. CPOM is part of C3S (the Copernicus Climate Services) Cryosphere Service, which is led by ENVEO IT GmbH (https://www.enveo.at).
Environmental tipping points occur when warming temperatures lead to changes in the climate system which pass a threshold and become irreversible. Passing these points will lead to changes to sea level, ocean circulation and our weather, something world leaders need to plan for in advance. That’s why it’s vital to monitor for signs we are coming close to and passing these tipping points.
Combining observation and modelling expertise with innovative sensing systems, the programme aims to develop sensing systems for monitoring the Earth’s ice and oceans and place these systems in locations such as the Greenland Ice Sheet and the Subpolar Gyres (ocean circulation systems which sit under an area of constant low atmospheric pressure); both of which have been identified as crucial climate tipping points.
The programme will also look at developing improved models (computer simulations) to produce more robust and accurate predictions of these tipping points and the potential impact on the planet.
The programme is made up of 27 international teams of experts in climate science, maths, computer science, statistics, optics, photonics, and nuclear physics – bringing together this expertise to develop the best possible early warning system for these climate tipping points.
CPOM members are supporting three of these teams:
CryoWatch: Aims to progress the development of affordable, solar-powered, High Altitude Pseudo Satellites (HAPS), to be stationed in the stratosphere for persistent monitoring of polar regions. Led by Steve Tate (Voltitude), the team includes CPOM Co-Director of Science, Professor Mal McMillan.
OptimISM: A Next-Generation Framework for Ice Sheet Modelling. Led by Trystan Surawy-Stepney (University of Leeds), the team includes CPOM Principal Investigator: Land Ice Modelling, Dr Steph Cornford (University of Bristol).
PROMOTE: Progressing Earth System Modelling for Tipping Point Early Warning Systems. Led by Reinhard Schiemann (University of Reading and National Centre for Atmospheric Science), the team includes CPOM Principal Investigator: Land Ice Modelling, Dr Steph Cornford (University of Bristol).
Greenland is a fascinating and beautiful country, with a population of more than 50,000 people. It has long been a key area of focus for polar scientists, due to the importance of observing and modelling of changes to the Greenland ice sheet. This huge expanse of ice, the second largest land ice mass in the world, is more than 2000km in length, 1000km wide and at its thickest point is over 3km thick.
And this ice sheet is melting.
Melting ice sheets directly contribute water to the oceans, leading to sea level rise. This influx of cooler water also affects the ocean circulation, with implications for global weather patterns. Accurately tracking melting of the Greenland and Antarctic ice sheets is essential to ensure people all over the world can prepare for the effects of climate change.
As ice sheets are so huge they are incredibly difficult to fully measure in person. Satellite measurements are the only ways we can accurately measure these vast areas.
CPOM has provided assessments of the amount of ice stored in the Greenland and Antarctic ice sheets since 2018, via the IMBIE Project (Ice Sheet Mass Balance Intercomparison Exercise) which uses three decades of satellite data to assess the ice sheets. You can read their most recent report in Earth System Science Data from 2023, which estimates ice losses from these regions since 1992.
Another recent study from December 2024, led by CPOM PhD Researcher, Nitin Ravinder, and published in Geophysical Research Letters, showed that the Greenland ice sheet lost 2347 km3 of ice during the period since 2010 – which has contributed roughly ‘the amount of water stored in Africa’s Lake Victoria’ to the Earth’s oceans. Here’s an animation from Planetary Visions based on this study showing these changes in the Greenland ice sheet.
As sea level rise will affect many millions of people around the world, as well as the numerous at-risk species in coastal habitats, it’s vital that Governments and international bodies are able to plan for this rise. Computer modelling (simulations) is the only way we can accurately predict how the ice sheets might behave in the future.
CPOM provides UK National Capability research in ice sheet modelling, developing the BISICLES model.
BISICLES is a numerical model (simulation) that works with high resolution simulations around the margins of ice sheets (the grounding line), where interactions between the ice sheet and the ocean and atmosphere are the most complex. This is particularly useful when looking at the Greenland ice sheet.
Scientists from CPOM recently worked on combining this system as the ice sheet component within the UKESM (The UK Earth System Model), allowing us to better explore and understand the interactions between the ice sheets and the global ocean and atmospheric circulations (and providing evidence for IPCC reporting).
BISICLES has also been integrated into large international projects such as ISMIP (Ice Sheet Model Intercomparison Project) to help project future changes to global sea levels, something that is particularly difficult to predict beyond the end of the century with one model alone.
The behaviour of the Greenland ice sheet is particularly difficult to predict, as over recent years we have seen points where melting has been more rapid than anticipated, but also points where it has been less than expected. We need to continually hone and improve computer simulations (or models) that can accurately predict how these ice sheets might behave in a rapidly warming planet to account for the complexity of the interactions between the ice sheets and the atmosphere in these regions.
Understanding this part of the world is vital for understanding how we might protect the rest of the Earth in the years to come. By combining expertise in land ice Earth observation with modelling simulations, like BISICLES, CPOM is continuing to increase the accuracy of future projections of sea level rise and weather changes, leading from the melting of the Greenland ice sheet.
Global warming is driving the rapid melting of the Greenland Ice Sheet, contributing to global sea level rise and disrupting weather patterns worldwide. Because of this, precise measurements of its changing shape are of critical importance for adapting to climate change.
Now, scientists from the UK Centre for Polar Observation and Modelling have delivered the first measurements of the Greenland Ice Sheet’s changing shape using data from ESA’s CryoSat and NASA’s ICESat-2 ice missions.
Although both satellites carry altimeters as their primary sensor, they make use of different technologies to collect their measurements. CryoSat uses a radar system to determine Earth’s surface height, while ICESat-2 uses a laser system for the same task.
Although radar signals can pass through clouds, they also penetrate the ice sheet surface and have to be adjusted to compensate for this effect. Laser signals, on the other hand, reflect from the actual surface but cannot record when clouds are present. The missions are therefore highly complementary, and combining their measurements has been a holy grail for polar science.
A new study from scientists at the CPOM and published today in Geophysical Research Letters, shows that CryoSat and ICESat-2 measurements of Greenland Ice Sheet elevation change agree to within 3% of the changes taking place.
This confirms that both satellites can be combined to produce a more reliable estimate of ice loss than either could achieve alone. It also means that if one mission were to fail, the other could be relied upon to maintain our record of polar ice change.
Between 2010 and 2023, the Greenland Ice Sheet thinned by 1.2 m on average. However, much larger changes occurred across the ice sheet’s ablation zone where summer melting exceeds winter snowfall; there, the average thinning amounted to 6.4 m.
Image credit: Professor Andrew Shepherd (Northumbria University)
The most extreme thinning occurred at the ice sheets outlet glaciers. At Sermeq Kujalleq in west central Greenland (also known as Jakobshavn Isbræ), the peak thinning was 67 m, and Zachariae Isstrøm in the northeast the peak thinning was 75 m.
Altogether, the ice sheet shrank by 2347 cubic kilometres across the 13-year survey period – similar to the amount of water stored in Africa’s Lake Victoria. The biggest changes occurred in 2012 and 2019, when the ice sheet shrank by more than 400 cubic kilometres because of extreme melting in those years.
Greenland’s ice melting also has profound effects on global ocean circulation and weather patterns. These changes have far-reaching impacts on ecosystems and communities worldwide. The availability of accurate, up-to-date data on ice sheet changes will be critical in helping us to prepare for and adapt to the impacts of climate change.
“We are very excited to have discovered that CryoSat and ICESat-2 are in such close agreement,” says lead author and CPOM researcher Nitin Ravinder. “Their complementary nature provides a strong motivation to combine the data sets to produce improved estimates of ice sheet volume and mass changes. As ice sheet mass loss is a key contributor to global sea level rise, this is incredibly useful for the scientific community and policymakers.”
The study made use of four years of measurements from both missions, including those collected during the Cryo2ice campaign, a pioneering ESA-NASA partnership initiated in 2020. By adjusting CryoSat’s orbit to synchronise with ICESat-2, ESA enabled the near-simultaneous collection of radar and laser data over the same regions.
This alignment allows scientists to measure snow depth from space, offering unprecedented accuracy in tracking sea and land ice thickness.
Tommaso Parrinello, CryoSat Mission Manager at ESA, expressed optimism about the campaign’s impact: “CryoSat has provided an invaluable platform for understanding our planet’s ice coverage over the past 14 years, but by aligning our data with ICESat-2, we’ve opened new avenues for precision and insight.
CryoSat Image Credit: European Space Agency
“This collaboration represents an exciting step forward, not just in terms of technology but in how we can better serve scientists and policymakers who rely on our data to understand and mitigate climate impacts.”
“It is great to see that the data from ‘sister missions’ are providing a consistent picture of the changes going on in Greenland,” says Thorsten Markus, project scientist for the ICESat-2 mission at NASA.
“Understanding the similarities and differences between radar and lidar ice sheet height measurements allow us to fully exploit the complementary nature of those satellite missions. Studies like this are critical to put a comprehensive time series of the ICESat, CryoSat-2, ICESat-2, and, in the future, CRISTAL missions together.”
ESA’s CryoSat continues to be instrumental in our understanding of climate related changes in polar ice, working alongside NASA’s ICESat-2 to provide robust, accurate data on ice sheet changes. Together, these missions represent a significant step forward in monitoring polar ice loss and preparing for its global consequences.
Ice sheet models (scientific simulations which aim to predict future behaviour of ice sheets) often disagree on the timing and magnitude of sea level rise up until 2300. For example, projections of Antarctica’s contribution to sea level rise beyond 2100 remain highly uncertain due to processes such as Ice Sheet and Ice Cliff instability which could cause Antarctic melting to contribute more rapidly to sea level rise.
The Coupled Model Intercomparison Project Phase 6 (CMIP6) is an international effort using different climate models to better understand how the Earth’s climate system responds to various factors. ISMIP6 (Ice Sheet Model Intercomparison Project for CMIP6), co-led by CPOM, is the part of CMIP6 project that examines the ice sheets, aiming to improve predictions of their future contribution to sea level rise, which is critical to assess the impact of melting ice on sea level rise, oceans currents, and weather patterns. By pulling together a range of different models, ISMIP6 supports the scientific community by producing more accurate, robust, multi-century projections of sea level rise and quantifying their associated uncertainties.
The most recent report using the ISMIP6 Model ensemble was released on Wednesday 4 September) in the AGU Earth’s Future journal. The new study (Seroussi et al). investigates the behaviour of the Antarctic Ice Sheet until 2300 using an ensemble of 16 ice-flow models and forcing from global climate models. This is the first multi-century, multi-model projections of the Antarctic Ice Sheet evolution and shows that ice flow models are relatively consistent in predicting a limited Antarctic sea-level rise up until 2100. However, beyond the end of this century, Antarctica’s ice losses increase rapidly thereafter with the choice of ice flow model and different potential influential factors such as carbon emissions (known as climate forcing scenarios) becoming sources of uncertainty.
This model ensemble shows that, under high carbon emission scenarios, some simulations show high levels of ice retreat after 2100 with potential sea level rise of up to 1.7m in 2200 and 4.4 m by 2300. In particular, key regions in West Antarctica, including the Bungenstock Ice Rise, the Siple Coast and the Amundsen Sea sector are predicted to undergo rapid retreat. Results saw strong variations between models on the onset of retreat but good agreement on the pattern of retreat.
In addition to the choice of ice sheet model, this study also highlights the importance of the emission scenario, as ice losses under both low and high emissions remain similar during the 21st century, the two scenarios produce significantly varied results post 2100. This highlights the importance of reducing emissions for the future stability of the Antarctic Ice Sheet as well as the importance of further work on developing and improving accurate and robust models of ice shelf retreat and potential collapse beyond 2100 so that policy makers and scientists can make decisions today which will protect the future of Antarctica beyond tomorrow.
£8.4M has been awarded to the British Antarctic Survey and the Centre for Polar Observation and Modelling to deliver the next 5 years of their long-term polar science activities. The UK Polar Research Expertise for Science and Society (PRESCIENT) programme provides UK national capability (science, such as ongoing datasets and models, which underpins wider scientific research) to understand the impacts of environmental stressors, such as rising global temperatures on polar marine ecosystems. PRESCIENT will also measure and predict polar ice sheet contributions to global sea level rise and extend and improve measurements of changes to polar sea ice.
Announced today the funding is part of £101 million investment by the Natural Environment Research Council, part of UK Research and Innovation, in the UK’s network of leading environmental science research centres to support large-scale environmental observations, modelling and analysis, and research capabilities through innovations in platforms, sensors and data science. These data are crucial for managing natural resources, biodiversity, human health and building our understanding of and resilience to environmental hazards and climate change. It underpins science across the UK’s environmental research sector and supports critical scientific advice to government.
National capability is research funding which, unlike shorter term projects, can span decades and provides ongoing support for large-scale, complex scientific projects of national significance, informing strategic needs and decision-making of the country. Using techniques such as satellite altimetry to study ice motion and the polar oceans, CPOM incorporate the results into models used across the polar research community. CPOM’s data sets and models have been developed and maintained for almost a quarter of a century, and the long-term maintenance of this capability helps provide robust understanding and insights of the cryosphere.
CPOM also contribute to a range of interdisciplinary multi-centre National Capability research projects including CANARI, BIOPOLE, and TerraFIRMA, which have been running since 2022, offering satellite derived estimates of aspects of the cryosphere (such as ice thickness, floe size and sea height), as well as developing advanced simulations. The longevity of our datasets, and the accuracy of our models mean we have a broader view of past and possible future changes. By contributing to projects such as the previous multi-centre National Capability project UKESM (UK Earth System Model), integrating ice sheet model and advanced sea ice physics into the system, we can produce robust projections of ice sheet instability and Arctic sea ice loss, thereby informing sea level rise predictions. Our PRESCIENT programme with BAS continues this work into 2029.
This funding has been awarded from NERC’s National Capability Single Centre Science initiative, one of the UK’s largest environmental science investment programmes.
This week we watched along with many across the globe, as pioneer European satellite ERS-2 finally made its journey back to earth after almost 30 years monitoring earth from the sky.
For many current and former CPOM scientists, this was an emotional moment, as the data from this satellite has made (and continues to make) an integral contribution to understanding the cryosphere. In fact, CPOM Director Professor Andrew Shepherd used ERS-2 data for his first paper 23 years ago ‘Inland Thinning of Pine Island Glacier, West Antarctica’ which used satellite altimetry and interferometry to show that the glacier ‘had thinned by up to 1.6 meters per year between 1992 and 1999’.
Part of the European Space Agency’s (ESA) earth observation programme, the revolutionary satellite was launched in April 1995 into a sun-synchronous polar orbit at an altitude of around 800 km, and was one of the most powerful and sophisticated satellites of its time.
Due to its three-axis stabilization it was able to point directly towards our planet and could observe most areas of the earth, using SAR (Synthetic Aperture Radar) to view land surfaces, polar ice and oceans, measuring ocean-surface temperature, sea winds and sea level changes via Radar Altimetry. On top of this it could also monitor ozone levels.
The data this satellite collected has been crucial in monitoring land surface changes, warming oceans, natural disasters, and importantly for the Centre for Polar Observation and Modelling – monitoring diminishing polar ice and sea-level rise. ERS-2 (and it’s twin ERS-1 launched a few years prior) paved the way for other programmes including the EU Space program’s Copernicus Sentinels and ESA’s CryoSat Earth Explore Mission, both of which continue to provide vital data for CPOM’s research. In fact, we are using ERS-2 data to extend our datasets further back in time, in order to create a fuller view of the evolution of the cryosphere over the last 30 years.
It was retired in 2011 and has been de-orbiting since then. Now it’s 16-year journey home is complete, broken and burned up in the atmosphere with the remaining parts landing safely in the ocean yesterday but even though the physical entity is gone, the data it produced, having been used for thousands of scientific papers, continues to provide information for scientists at ESA, CPOM and beyond.
New research states that future rises in sea level could be better estimated by gaining a clearer understanding of the Antarctic and Greenland ice sheets.
Global climate change and its impact on sea levels is a pressing issue and trying to accurately predict just how much they will rise in future is subject to ongoing analysis. The changing nature of ice sheets is a vital factor in the projection of future sea level rise.
Led by the University of Lincoln and involving Dr Sammie Buzzard from the Centre for Polar Observation and Modelling (Northumbria University), the paper was published today in the Nature journal, Nature Reviews Earth & Environment.
An important aspect of the review highlights that short-term fluctuations in climate could have an amplification feedback effect, meaning that ice sheets are more sensitive to climate change than previously understood.
During the melt season (typically from May to September) on the Greenland ice sheet, water collects in depressions on the surface of the ice, creating supraglacial lakes. If these lakes have enough water and the right conditions, they can crack open (hydrofracture) which allows water to flow from the ice surface down to the bedrock underneath, where it acts like a lubricant. These lakes on the Greenland ice sheet are incredibly important, but identifying exactly how deep they are using satellite data is difficult.
This research compares different ways of measuring the depth of these supraglacial lakes, using tools including a radiative transfer equation (RTE), ArcticDEM digital elevation models, and ICESat-2 photon refraction. The team of researchers led by CPOM PhD Researcher Laura Melling (Lancaster University) applied these methods to five lakes in southwest Greenland.
The paper examines the uncertainty in these estimates, which affects our understanding of the total lake volume and how that, in turn, can interfere with predictions about how fast the ice is moving. This work demonstrates how combining information from multiple different satellite sources can improve our ability to track meltwater on top of the Greenland Ice Sheet.
Authors include: CPOM PhD Researcher Laura Melling (Lancaster University), CPOM Associate Investigator Amber Leeson, CPOM Principal Investigator Malcolm McMillan (Lancaster University), CPOM Senior Research Associate Jennifer Maddalena (Lancaster University), Jade Bowling (Lancaster University), CPOM PhD Researcher Emily Glen (Lancaster University), Louise Sandberg Sørensen (Technical University of Denmark), Mai Winstrup (Technical University of Denmark), and Rasmus Lørup Arildsen (Technical University of Denmark).
CPOM publishes paper on ‘Multipeak retracking‘ introducing a new processing approach, aimed at overcoming challenges associated with using radar altimetry to measure ice sheet changes over rugged coastal topography in Antarctica and Greenland.
This new MultiPeak processing approach which is applied to data from the Copernicus Sentinel-3 mission, significantly improves the accuracy and quantity of elevation retrievals and and has the potential to enhance the capability of SAR altimeters to track ice sheet imbalance. This is an important step forward in developing more sophisticated monitoring approaches for tracking ice loss in the most complex regions which contribute to global seal level rise. The paper is co-authored by CPOM Senior Research Associate Dr Qi Huang (Lancaster University), CPOM Associate Investigator Professor Mal McMillan (Lancaster University), CPOM Systems, Data, Product Manager Alan Muir (UCL), CPOM Affiliate Joe Phillips (Lancaster University) and CPOM Research Fellow Dr Thomas Slater (Northumbria University).
