An international research team led by scientists from the University of Vienna, together with colleagues at BOKU University and the Austrian Academy of Sciences, analysed vegetation records from 62 European mountain summits that were surveyed four times between 2001 and 2022. The plots form part of GLORIA, the Global Observation Research Initiative in Alpine Environments, a worldwide monitoring network coordinated from Austria that uses standardised multi-summit plots to track vegetation change across elevation gradients. Because every summit in the network is revisited on the same schedule and with the same methods, the dataset offers an unusually clear window into how alpine plant communities respond to a warming climate in near real time.

The underlying mechanism is straightforward. Until a few decades ago, short growing seasons, low accumulated warmth and the risk of frost at any time of year made Europe’s alpine landscapes effectively impenetrable to many lowland and montane species. Accelerating climate warming has relaxed these constraints, allowing plants to expand their ranges upward. Summit vegetation has consequently become more species-rich, a pattern documented repeatedly across mountain ranges on several continents. What the new analysis adds is the other side of the ledger: an explicit, quantified account of the species that vanish from these same summits, and of how quickly those disappearances are accelerating.

The data show that the percentage of species not re-detected on a given summit increased with each successive survey period. In other words, local extinctions are not a rare background process but a growing one, and the trend has strengthened over the past two decades. Crucially, the losses were not distributed randomly across the flora. Species whose centres of distribution lie above the elevation of the focal summit were significantly overrepresented among those that disappeared. These are the cold-adapted specialists of the highest zones, the cushion plants, mosses and rosette herbs that have nowhere higher to go and that give alpine ecosystems their distinctive character.

The study’s statistical analysis points unambiguously to warming as the driver. First author Johannes Wessely of the University of Vienna notes that species were more likely to disappear from summits that experienced stronger warming, and that this correlation with the magnitude of temperature increase was even stronger than the simple passage of time. That distinction matters scientifically: if extinctions merely tracked the calendar, any number of unrelated processes could be responsible. The fact that the loss rate scales with the degree of warming experienced at each site identifies rising temperatures as the proximate cause of the accelerating disappearances.

Position within a species’ overall range turned out to be a second powerful predictor. The likelihood of local extinction increases towards the lower elevational margin of a species’ current distribution. Harald Pauli, coordinator of the GLORIA network at the Austrian Academy of Sciences and BOKU University, explains the implication plainly: when species already grow on warmer-than-average sites, they become more sensitive to further temperature increases. Populations at the warm edge of a range are, in effect, living closest to their physiological limits, so each additional fraction of a degree pushes them closer to the threshold beyond which they can no longer persist on a given summit.

One of the most conceptually important findings concerns timing. The specialists of high elevations tend to be particularly stress-tolerant and long-lived. Individual plants of some alpine species can survive for many decades, and their populations can persist in declining condition long after the environmental conditions that once sustained them have gone. This means local extinction can lag far behind the onset of the environmental changes that ultimately trigger it, a phenomenon ecologists describe as an extinction debt. Biological communities accumulate invisible losses that will only become apparent years or decades later, when the last surviving individuals of a doomed population finally die out.

This lag effect has long been the leading explanation for an asymmetry in alpine vegetation records: colonisations by new species arriving from below have been documented far more frequently than extinctions of established residents. The new results fit that interpretation closely. The analysis found that local extinctions are typically preceded by longer phases of population decline, meaning that the disappearances recorded between surveys are the end point of processes that began much earlier. Stefan Dullinger, project coordinator of the study, emphasises that the elevated extinction rates observed today could therefore indicate that an extinction debt accumulated over past decades is now starting to be paid off, although he cautions that whether this interpretation holds true needs further investigation.

The implications of that possibility are sobering. If current extinction rates reflect warming that occurred or at least began decades ago, then the losses already locked into alpine communities exceed what the monitoring record shows today. The full cost of twentieth-century and early twenty-first-century warming may still be working its way through populations of long-lived mountain plants, with further disappearances inevitable even under optimistic emissions scenarios. At the same time, the accelerating trend means that new debts continue to accumulate, stacking future losses on top of those already in the pipeline. For the cold-adapted specialists of Europe’s highest summits, there is little room for upward retreat: many already occupy the top of their mountains, and the regional species pool offers no replacement flora adapted to the harshest summit conditions.

The study reframes a widely cited indicator of climate change impact. Rising species richness on mountain summits has often been presented as evidence that alpine biodiversity is, for now, benefiting from warming. The new analysis shows that this metric is misleading on its own, because it counts arrivals while ignoring departures and because the departures disproportionately remove the species that are most characteristic of alpine ecosystems. Biodiversity change, the authors argue, must be assessed on both sides of the ledger simultaneously. The research was funded by the European Research Council under the European Union’s Horizon 2020 research and innovation programme, grant agreement number 883669, and the long-term GLORIA monitoring that made it possible continues across summit sites worldwide, providing the observational foundation needed to test whether the extinction debt now visible on Europe’s mountaintops will continue to grow.

Subject of Research: Accelerating climate-driven local extinctions of high-elevation specialist plants on European mountain summits

Article Title: Rising plant extinction rates on European mountain summits

Article References: Rising plant extinction rates on European mountain summits. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: alpine plants, mountain summits, climate warming, local extinction, extinction debt, GLORIA, biodiversity monitoring, species range shifts, high-elevation specialists, European Alps, vegetation change, Science journal

The scientific foundation for the website is the first global assessment of the disappearance of individual glaciers, led by researchers from ETH Zurich and Vrije Universiteit Brussel together with an international team. Rather than aggregating ice loss into global totals of mass or area, the study tracked the projected lifetimes of individual glaciers, introducing the concept of peak glacier extinction: the period during which the annual number of vanishing glaciers reaches its maximum. According to the projections, the world is approaching an era of unprecedented glacier extinction. Lead author Lander Van Tricht of ETH Zurich and Vrije Universiteit Brussel developed the website together with Kristof Van Tricht of VITO Remote Sensing, converting dense model output into an accessible visual interface that anyone can explore.

The technical engine behind the projections draws on global glacier evolution models driven by climate scenarios from the Coupled Model Intercomparison Project, published in the journal The Cryosphere in 2024 by Harry Zekollari and colleagues. These models simulate how each glacier responds to changing temperature and precipitation, accounting for glacier-specific characteristics such as size, elevation, geometry and local climate. The results are stark. Under global warming limited to 1.5 degrees Celsius, around 2,000 glaciers per year are projected to disappear worldwide at the peak of extinction, a figure that roughly doubles under 4 degrees of warming. By the end of the century, nearly half of today’s glaciers could survive at 1.5 degrees, compared with about 20 percent at 2.7 degrees and fewer than 10 percent at 4 degrees.

Regional contrasts are even more dramatic than the global averages suggest. In the European Alps, one of the most heavily glaciated and closely monitored mountain ranges on Earth, the models indicate that only around 110 glaciers may remain under 2.7 degrees of warming, and as few as 20 under 4 degrees. The smallest glaciers, which dominate the Alps numerically, are the most vulnerable because they have little mass to lose and warm air temperatures can strip away an entire ice body within a few extreme summers. The study’s projections are already being tested against reality. In August 2026, the Bella Tola Glacier near Saint-Luc in Switzerland was officially declared extinct after almost completely disappearing, a timing that falls squarely within the extinction window of 2026 to 2029 projected for it in the Nature Climate Change study.

Bella Tola is not an isolated case. The Urirotstock Glacier, also in Switzerland, was declared extinct during the same summer, offering a second tangible example of the rapid disappearance of the country’s smallest glaciers. The 2026 melt season has been particularly punishing for Alpine ice: preliminary end-of-summer measurements, still ongoing, suggest it could become one of the worst years for glaciers in the European Alps since systematic observations began. A combination of meagre winter snow accumulation and repeated summer heatwaves produced substantial ice loss across the range. For glaciers already reduced to thin, dirty remnants, scientists note, a single additional extreme melt season can push them past the threshold of survival, turning a decades-long decline into a definitive end.

Researchers are careful to emphasise that the disappearance of a glacier is rarely the work of one hot summer. As co-author Harry Zekollari of Vrije Universiteit Brussel explains, extinction is the culmination of decades of cumulative mass loss, in which insufficient snowfall year after year and strong summer melt gradually reduce a glacier until it can no longer sustain itself. Glaciers survive through a balance between accumulation, the snow that compacts into ice at high elevations, and ablation, the melting and calving that remove ice lower down. When warming shifts that balance persistently into deficit, the ice thins, retreats upslope, fragments and finally vanishes. Extreme melt years such as 2022 or 2026 can accelerate this final stage dramatically, but they act on glaciers already weakened by long-term imbalance.

The website’s designers stress that the projected extinction years should be read as estimates rather than exact predictions. Individual glaciers respond differently depending on their size, elevation, geometry and the specifics of their local climate, and the future trajectory of global warming itself remains uncertain, dependent on emissions choices made over the coming decades. What the tool provides instead is a robust picture of how strongly a glacier’s lifetime depends on future warming, and an approximate window within which its disappearance becomes likely under each scenario. By selecting different warming levels, users can see how each additional fraction of a degree compresses the survival prospects of ice bodies from the Andes to the Himalaya, from the Alps to Arctic archipelagos.

That sensitivity to warming levels carries a clear message about mitigation. According to the researchers, limiting global warming to 1.5 degrees Celsius could preserve more than twice as many glaciers by 2100 as a 2.7-degree trajectory, a difference that translates into thousands of individual ice bodies and the ecosystems, water supplies and cultural values attached to them. Glaciers are far more than scenic ice masses: they regulate downstream water availability for agriculture and hydropower, sustain unique cold-adapted ecosystems, anchor mountain tourism economies and hold deep significance for the communities that live in their shadow. Van Tricht notes that behind every disappearing glacier lies a place, a history and often a community that will experience its absence, and that global numbers of mass loss, however accurate, cannot convey that reality.

The launch of the Global Glacier Extinction Explorer arrives at a moment when the abstraction of glacier science is collapsing into lived experience. Glaciers projected in the study to disappear within years are already vanishing, confirming that glacier extinction is not a distant end-of-century problem but a process unfolding now, in valleys where families have skied, farmed and mourned beneath the same ice for generations. By making the projections searchable, visible and personal, the researchers hope the website will help local communities prepare for futures with fewer or no glaciers, while giving policymakers and the public a vivid, glacier-by-glacier illustration of what every fraction of a degree of avoided warming would preserve. The future of the world’s remaining ice, the tool makes clear, is still being written.

The ability to project the fate of every glacier on Earth rests on decades of patient fieldwork. Glaciologists have tracked the front positions of Alpine ice since the late nineteenth century, and systematic mass balance programmes, in which teams measure winter snow gain and summer melt on individual glaciers year after year, now span several continents. These long observation records are what allow modellers to calibrate their simulations and check whether a glacier’s computed behaviour matches its measured reality. Without such calibration, projections of extinction dates would carry far less credibility.

Global glacier inventories have also transformed what is possible. Satellite imagery and aerial surveys have catalogued well over two hundred thousand individual glaciers worldwide, most of them small features that a casual observer might overlook. This completeness matters because the extinction statistics are dominated by these small ice bodies: a single large ice cap may persist for centuries, while hundreds of small cirque and valley glaciers in the same region can vanish within decades. Counting glaciers rather than tonnes of ice therefore shifts attention to the many places where loss will be total rather than partial.

The hydrological consequences of extinction are subtle and often counterintuitive. As a glacier shrinks, its accelerated melt initially boosts summer water supplies to downstream rivers, a phenomenon sometimes described as peaking water. Once the ice mass falls below a critical size, that contribution declines irreversibly, leaving communities that depend on glacier-fed streams for irrigation, drinking water or hydropower facing reduced late-summer flows precisely when demand is highest. The timing of this transition varies enormously between regions, which is why glacier-specific projections are more useful than regional averages.

There are also limits worth acknowledging in the underlying science. Global glacier models must simplify processes such as debris cover, which insulates some ice from melt, avalanche feeding, which sustains certain glaciers beyond what climate alone would allow, and the dynamic response of tidewater glaciers to ocean conditions. These simplifications tend to matter most for individual glaciers, reinforcing the researchers’ caution that extinction years are windows of likelihood rather than appointments. Continued monitoring, including the kind of end-of-summer field measurements underway in the Alps this year, provides the ongoing reality check that keeps such projections honest and allows them to be refined as the century progresses.

Subject of Research: Global projections of individual glacier disappearance and the timing of peak glacier extinction under different warming scenarios

Article Title: When will your glacier disappear? From projections to reality: new website maps the future of every glacier on Earth

Article References: When will your glacier disappear? From projections to reality: new website maps the future of every glacier on Earth. (n.d.). Original publication

Image Credits: AI Generated

DOI: Not provided

Keywords: glaciers, climate change, glacier extinction, sea level rise, global warming, interactive map, European Alps, glacier models, water resources, Nature Climate Change, ETH Zurich, Vrije Universiteit Brussel