The Siberian tundra is one of Earth’s largest and most sparsely vegetated biomes, stretching across northern Russia from the Ural Mountains to the Pacific coast. Its climate is defined by long, brutally cold winters, brief summers, and continuous permafrost that shapes everything from the plants that grow to the animals that migrate across it. Over the past few decades, warming temperatures have set off a cascade of changes in this landscape: the frozen ground is softening, shrubs are creeping northward, wildfires are burning where they historically did not, and the people and animals that depend on the tundra are adapting in real time.
A Climate Built on Cold and Permafrost
Winter on the Siberian tundra can last eight or nine months, with temperatures routinely dropping below minus 40 degrees. Summers are short and cool but surprisingly intense; near-continuous daylight drives a burst of biological activity. The region sits in the zone of continuous permafrost, meaning the ground remains frozen year-round beneath a thin “active layer” that thaws each summer and refreezes in autumn. On Samoylov Island in the Lena River Delta, a long-running research station at 72° N latitude, scientists have tracked this freeze-thaw cycle since the late 1990s, documenting the interplay between air temperature, snow cover, and ground ice that defines tundra conditions.1Biogeosciences. Baseline characteristics of climate, permafrost and land cover from a new permafrost observatory in the Lena River Delta, Siberia (1998–2011)
Precipitation is low, often comparable to a desert, but because so little water evaporates in the cold air, the landscape stays waterlogged. Snowmelt pools on the surface because permafrost acts as an impermeable floor. The result is a mosaic of wetlands, shallow lakes, and soggy ground that supports a surprisingly productive ecosystem during the brief growing season.
How Tundra Plants Survive
No trees grow on the true tundra. The vegetation is low to the ground: mosses, lichens, sedges, grasses, and dwarf shrubs that rarely stand taller than knee height. These plants share a toolkit of survival strategies. Most are perennials that store energy underground between seasons, keeping the bulk of their biomass in roots and rhizomes safely insulated below the surface. Growth is rapid once the snow melts, even at temperatures just above freezing, because tundra plants have evolved to photosynthesize efficiently in cool conditions.2Biological Reviews. THE ECOLOGY OF ARCTIC AND ALPINE PLANTS
Frost resistance is tied to concentrations of soluble sugars, particularly raffinose, which act as a kind of antifreeze inside plant cells. Drought stress is a real threat, not in summer but in winter, when frozen soils prevent water uptake and dry winds strip moisture from any exposed tissue. Many species cope by closing the tiny pores on their leaves and concentrating soluble carbohydrates. Nutrient scarcity in the cold soil, especially nitrogen and phosphorus, keeps growth modest even in the best conditions.3AMBIO: A Journal of the Human Environment. Biodiversity, Distributions and Adaptations of Arctic Species in the Context of Environmental Change
Wildlife and the Food Webs That Drive It
The Siberian tundra supports a surprisingly rich animal community, though much of it depends on a few keystone relationships. On the Taimyr Peninsula, researchers tracked lemmings and Arctic foxes for four decades and found that the number of fox dens occupied by breeding pairs closely tracked lemming abundance.4Ornis Svecica. Population dynamics of lemmings, Lemmus sibirica and Dicrostonyx torquatus, and Arctic Fox Alopex lagopus on the Taimyr peninsula, Siberia, 1960—2001 These boom-and-bust cycles ripple through the ecosystem. When lemmings crash, foxes switch to raiding bird nests, putting pressure on ground-nesting species like waders and geese.
Tundra-breeding birds face growing conservation concerns. A circumpolar assessment found that over half of all Arctic wader species are declining, while waterfowl are faring better, with almost half of those populations increasing. The opposing trends are shifting community composition at some sites. Declines were least severe in the African-Eurasian flyway but similarly common across the other three global flyways.5PubMed Central. Status and trends of tundra birds across the circumpolar Arctic The causes are complex: habitat change on the tundra breeding grounds, hunting pressure along migration routes, and shifting predator dynamics all play a role.
Reindeer (and their wild counterparts, caribou) are arguably the most ecologically and culturally important large herbivores on the Siberian tundra. They are also among the most vulnerable to a changing climate, for reasons that have nothing to do with summer heat.
Rain on Snow and the Reindeer Crisis
One of the most damaging consequences of warming winters in the Arctic is the increase in rain-on-snow events. When rain falls on an existing snowpack and then refreezes, it forms a hard ice crust that reindeer cannot break through with their hooves to reach the lichen and dried vegetation underneath. Ice layers forming in late winter are especially dangerous because the animals are already weakened after months of cold and limited forage.6PubMed. Detection of snow surface thawing and refreezing in the Eurasian Arctic with QuikSCAT: implications for reindeer herding Satellite data have confirmed that rain-on-snow events on Russia’s Yamal Peninsula have caused severe impacts on reindeer herds through exactly this ice-crust mechanism.7The Cryosphere. Towards long-term records of rain-on-snow events across the Arctic from satellite data
The consequences can be catastrophic. Nenets reindeer herders on the Yamal Peninsula recall the winter of 2013–2014 as the worst in living memory. A thick layer of ice covered the entire tundra for months, and reindeer were physically unable to reach forage. Nearly half the peninsula’s reindeer population starved. The Nenets now refer to that winter as serad” po, a word that means both “year of the ice crust” and “misfortune, poverty, misery.”8Ecology and Society. The Yamal Nenets’ traditional and contemporary environmental knowledge of snow, ice, and permafrost
Nenets herders have developed an array of adaptive strategies in response. Depending on herd size, location, labor available, and social networks, households choose from approaches ranging from adjusting migration routes and timing to pooling herds with relatives or negotiating with industrial companies operating on their pastures.9Sibirica. Adaptive Strategies of Indigenous Nenets Reindeer Herders for Climate Change in Yamal These responses are remarkably diverse, and no two households handle the same event the same way.
The Permafrost Is Softening
Across northern permafrost regions, the active layer, the seasonally thawed soil above the permanently frozen ground, is getting deeper. A satellite-informed analysis covering 2003 to 2020 found that roughly two-thirds of the permafrost zone showed a deepening trend, at an average rate of about a tenth of a centimeter per year. Around 80 percent of individual monitoring sites confirmed the trend.10Environmental Research Letters. Widespread deepening of the active layer in northern permafrost regions from 2003 to 2020 The rate varies enormously depending on local soil type, elevation, and whether fires have recently disturbed the surface.
Summer warmth is the dominant driver. Longer-term monitoring shows that warmer summers directly deepen the active layer, while the severity of the preceding winter has no detectable independent effect once site-level differences are accounted for.11Communications Earth & Environment. Long-term monitoring of active layer thickness confirms global permafrost degradation In other words, it is the heat of summer, not the absence of cold in winter, that is chiefly pushing the thaw line downward.
Shrubs Moving North
One of the most visible signs of change on the Siberian tundra is the spread of taller shrubs into areas that were previously open. Using satellite imagery and machine learning, researchers studying the Siberian Low Arctic detected increases in tall shrub cover in all three landscapes they examined, but the pace varied enormously, from about 2 percent per decade in some places to over 26 percent per decade in others. Shrubs establish first on microsites with good drainage and favorable soil, and once they begin producing seeds, their presence warms the local environment enough to help more shrubs establish nearby.12Journal of Ecology. Landscape patterns of shrubification in the Siberian Low Arctic: A machine learning perspective
A broader survey using historical aerial photographs from the 1960s onward found that total cover of tall shrubs and trees increased at nine of eleven tundra-forest transition zones across Siberia. In northwest Siberia, alder cover expanded by 5 to 26 percent at different sites. In other parts of Siberia, larch cover increased modestly, though at one site it actually declined because thawing ice-rich permafrost destabilized the ground.13PubMed. Tall shrub and tree expansion in Siberian tundra ecotones since the 1960s Larch expansion has also been documented in the Polar Urals, where trees have pushed uphill into what was recently mountain tundra.14Forests. Reconstruction of the Expansion of Siberian Larch into the Mountain Tundra in the Polar Urals in the 20th—Early 21st Centuries
Shrubification creates a feedback loop. Taller, darker vegetation sticks up above the snow in winter, absorbing more solar radiation and lowering surface reflectivity. Models suggest that the vegetation changes already observed across the Arctic correspond to roughly a 1.75 percent decline in snow-season reflectivity, which warms the land surface further and promotes still more shrub growth.15PubMed Central. Modelling tundra vegetation response to recent arctic warming
Wildfire in a Landscape That Rarely Burned
Historically, tundra fires were uncommon. That is changing. The 2020 fire season in Siberia was unprecedented: recent estimates suggest that a single year accounted for roughly two-thirds of the region’s total burned area over the prior two decades.16Journal of Geophysical Research: Biogeosciences. Pre‐Fire Vegetation Conditions and Topography Shape Burn Mosaics of Siberian Tundra Fire Scars Within the Arctic Circle, more than a quarter of all recorded burned area across the entire study period occurred in 2020 alone, and that year saw the highest number of large fires exceeding 1,000 hectares.17PubMed Central. Peat fires contribute disproportionately to Siberian fire carbon emissions
Peat fires are a particular concern. About a third of burned area across Siberia occurs in peat-dominated regions, but in extreme years like 2020, that fraction spiked to over 43 percent. Peat fires burn deeply into carbon-rich organic soils, releasing stored carbon that accumulated over thousands of years. Some of these fires smolder through the winter, burrowing into insulating layers of organic soil and re-emerging the following spring as so-called “overwintering” or “zombie” fires. These overwintering fires are driven by summer temperature extremes and deep burning, and they can extend the fire season by igniting new surface fires months before the typical season begins.18Environmental Research Letters. Overwintering fires rising in eastern Siberia
Eroding Coastlines and Vanishing Lakes
The Siberian tundra meets the Arctic Ocean along thousands of kilometers of ice-rich coastline, and that boundary is retreating. Since the early 2000s, erosion of permafrost coasts has increased at 13 of 14 long-monitored Arctic sites, coinciding with warming temperatures, declining sea ice, and accelerating permafrost thaw.19Arctic Report Card. Coastal Permafrost Erosion In the Laptev Sea region of Siberia, mean annual erosion rates have roughly doubled from their long-term average, reaching over five meters of coastline lost per year at monitored sites.20Biogeosciences. Short- and long-term thermo-erosion of ice-rich permafrost coasts in the Laptev Sea region
Inland, the tundra’s thermokarst lakes, formed when ground ice melts and the surface collapses, are also in flux. A mapping effort in northeast Siberian coastal tundra identified 238 lakes that drained between 2000 and 2020, often abruptly. Drained lakes clustered along rivers and in areas underlain by ice-rich Yedoma deposits, where the ground is especially prone to subsidence.21Remote Sensing. Monitoring Thermokarst Lake Drainage Dynamics in Northeast Siberian Coastal Tundra When these lakes drain, they leave behind flat, dry basins that develop new vegetation, reshaping the landscape on timescales of years to decades.
What Lies Beneath: Carbon, Methane, and Mercury
Permafrost soils are among the planet’s largest carbon reservoirs, holding roughly twice as much carbon as the entire atmosphere. As the ground warms, microbial activity increases, and that stored carbon begins converting to carbon dioxide and methane. Offshore, the situation is similarly concerning. In the shallow seas of the East Siberian Arctic Shelf, subsea permafrost that has been inundated by rising sea levels is gradually warming from below. Bottom seawater temperatures, though still near freezing, can be up to 17 degrees warmer than the permafrost was before inundation, destabilizing methane hydrates locked in the sediment. When hydrates convert to free gas, the volume can increase by up to 200 times, and the overpressured gas moves upward wherever the sediment allows.22Nature Communications. Current rates and mechanisms of subsea permafrost degradation in the East Siberian Arctic Shelf Rising temperatures are expected to increase hydrate destabilization, the release of trapped methane, and the degradation of organic matter in thawing subsea permafrost.23Communications Earth & Environment. Triple-isotopic analyses pinpoint microbial methane release from subsea permafrost in the inner Laptev Sea
Carbon is not the only pollutant at stake. Permafrost soils in western Siberia contain large amounts of mercury, bound up with organic matter. As the permafrost boundary shifts northward and the active layer deepens, that mercury is mobilized into rivers. Measurements in western Siberian rivers show that the highest mercury concentrations and export fluxes occur right at the edge of the permafrost zone, where the thawed peat layer is deepest. Researchers predict that continued warming could double the amount of mercury exported by small rivers to the Arctic Ocean within the next 10 to 50 years.24PubMed. Enhanced particulate Hg export at the permafrost boundary, western Siberia
Infrastructure on Unstable Ground
Across Russia’s permafrost regions, buildings, pipelines, and roads were constructed on the assumption that the ground beneath them would stay frozen. That assumption is failing. Projections using multiple climate models suggest that several Russian permafrost regions will lose more than half their soil bearing capacity by the 2050s. Counterintuitively, the most vulnerable areas are not the coldest, most northern regions but the warmer, more populated southern permafrost zones. The relationship between ground temperature and bearing capacity is nonlinear: permafrost that is already close to thawing loses structural strength much faster per degree of warming than very cold permafrost does. Cities like Norilsk, Vorkuta, and Novyy-Urengoy, along with major oil and gas infrastructure, sit squarely in these high-risk zones.25Environmental Research Letters. Assessment of climate change impacts on buildings, structures and infrastructure in the Russian regions on permafrost Ground subsidence in ice-rich permafrost regions like the Sakha Republic is expected to further threaten the stability of roads and pipelines that connect remote communities to the rest of Russia.
Old Diseases, New Risks
In the summer of 2016, an anthrax outbreak struck the Yamal Peninsula, killing a 12-year-old boy and thousands of reindeer. The outbreak was widely attributed to the activation of anthrax spores from an old animal burial site exposed by permafrost thaw during a heat wave. A closer examination revealed that the permafrost in the area had been thawing rapidly for at least six years before the outbreak, suggesting the risk had been building for some time rather than being triggered by a single hot summer.26PubMed Central. Climatic Factors Influencing the Anthrax Outbreak of 2016 in Siberia, Russia The episode raised broader concerns about what else might be preserved in frozen ground: old burial sites, animal carcasses, and potentially other pathogens that could be exposed as the active layer deepens.
Can Herbivores Slow the Thaw?
One of the more unconventional ideas for slowing permafrost loss comes from Pleistocene Park, an experiment in northeast Siberia where researchers are reintroducing large herbivores to the tundra. The logic is straightforward: in winter, grazing animals trample and compact the snow as they move across the landscape searching for food. Compacted snow conducts cold more efficiently than fluffy, undisturbed snow, so the ground beneath a herd cools more than ground under a thick, insulating snow blanket. Model experiments based on conditions at the park suggest that increasing herbivore density could keep permafrost soils roughly two degrees cooler by the end of the century compared to a scenario without grazers.27Scientific Reports. Protection of Permafrost Soils from Thawing by Increasing Herbivore Density Two degrees is a substantial buffer in a system where a fraction of a degree per year pushes the active layer measurably deeper. Whether this approach could scale beyond a single experimental reserve is an open question, but it demonstrates how ecological processes and permafrost stability are more tightly linked than they might seem at first glance.