Climate change in the Arctic

• 1. Introduction

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  Climate change in the Arctic is reshaping a region that, by 2050, scientists expect to be profoundly different from anything currently alive. Warming is happening at three to four times the global average rate, a pace described as among the highest anywhere on Earth. On the 20th of June 2020, a temperature of 38 degrees Celsius was recorded inside the Arctic Circle for the first time. That reading was not expected in the region until at least 2100. An attribution study published in July 2020 found that the heat wave responsible for that record could, without human-caused warming, occur only once in 80,000 years. Scientists called it the strongest link between any single weather event and anthropogenic climate change ever found.

  The changes are not confined to thermometers. Sea ice is retreating. Permafrost is thawing. Forests are creeping north. Beavers are colonizing rivers that were once locked in ice. And the Arctic Ocean may see its first completely ice-free summer before 2050, an event with no precedent in the last 700,000 years. What happens in the Arctic does not stay in the Arctic. The questions driving this documentary are: how did the Arctic get here, what is being lost, and what does this mean for the rest of the planet?

• 2. A Record Written in Heat

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  The period from 1995 to 2005 was the warmest decade the Arctic had seen since at least the 17th century. Temperatures ran about 2 degrees Celsius above the 1951-1990 average. In Alaska and western Canada, the increase during that same window was 3 to 4 degrees Celsius. Research published in 2013 showed that Arctic temperatures had not reached their current levels in at least 44,000 years, and possibly not in as long as 120,000 years.

  Since 2013, the Arctic's annual mean surface air temperature has stayed at least 1 degree Celsius above the 1981-2010 mean in every recorded year. In 2020, that figure rose to 1.9 degrees above the same baseline. Between March and May of that year, average Arctic temperatures ran 10 degrees Celsius higher than normal. In 2016, January and February brought extreme anomalies that scientists described as far above anything recorded in the 1981-2010 reference period.

  The 2021 Arctic Monitoring and Assessment Programme report was prepared by more than 60 experts, scientists, and indigenous knowledge holders from Arctic communities, working from 2019 to 2021. The same year's IPCC Sixth Assessment Report confirmed that observed and projected warming were strongest in the Arctic. An article published in Nature on the 11th of August 2022 noted that multiple reports had placed Arctic warming at two to three times the global average since 1979, while also cautioning that a recently cited figure of a four-fold warming ratio may represent an extremely unlikely event. A July 2022 paper in Geophysical Research Letters found that the annual mean Arctic Amplification index had reached values exceeding four from roughly 2002 through 2022.

  The 16th Arctic Report Card, released by NOAA on the 14th of December 2021, described the 12-month period from October 2020 through September 2021 as the seventh warmest over Arctic land since records began in 1900. Its 2017 predecessor had already noted that the melting ice of the warming Arctic was unprecedented in the prior 1,500 years.

• 3. Ice, Permafrost, and Lakes

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  The Arctic Ocean is on a course toward its first ice-free summer most likely before 2050, with some projections placing that event in the late 2020s or early 2030s. That threshold would have no precedent in the last 700,000 years. Sea ice does regrow every Arctic winter, but entirely ice-free summers are expected to become progressively more frequent as warming continues.

  Permafrost, the frozen ground underlying roughly 18 million square kilometres of the Northern Hemisphere, holds an estimated 1,460 to 1,600 petagrams of soil organic carbon. A petagram is one billion tonnes. That is double the amount of carbon currently in the atmosphere. As permafrost thaws, that stored carbon becomes vulnerable to release as carbon dioxide and methane, with emissions already described as comparable to those of major industrialized countries.

  Field studies in northwest Greenland have added another layer to the picture. A January 2025 study published in the Proceedings of the National Academy of Sciences documented an abrupt, climate-driven transformation in Greenland's lakes following a season of record heat and rainfall. Lakes shifted from a blue, transparent state to a brown, opaque one. The study described changes to numerous physical, chemical, and biological lake features, calling the state changes unprecedented. Earlier research from sites near the village of Siorapaluk showed that unprecedented rain events in 2016-2017 caused widespread mass movement processes, reshaped the landscape, and damaged archaeological sites. Approximately a quarter of the surveyed archaeological landscape was affected, with those erosion events providing a measure of long-term slope stability since the late Holocene.

  In 2024, the Arctic crossed another threshold: it shifted from being a net carbon sink to a net carbon source, driven mainly by rising temperatures and an increase in wildfire activity.

• 4. The Greening and What It Costs

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  NASA and NOAA have tracked Arctic vegetation using satellite instruments including the Moderate Resolution Imaging Spectroradiometer, known as MODIS, and the Advanced Very-High-Resolution Radiometer, or AVHRR. Their data makes it possible to calculate what researchers call Arctic greening and Arctic browning. Between 1985 and 2016, greening occurred at 37.3% of all tundra sites sampled; browning was seen at only 4.7% of sites, generally those still experiencing cooling and drying.

  The dominant pattern within that greening is a shift from mosses and lichens toward shrub-type plants. Shrubs are expanding in both range and biomass. Cushion plants such as moss campion, by contrast, may decline. Cushion plants serve as facilitator species across trophic levels and fill important ecological niches, so their decline could trigger cascading effects through the ecosystems that depend on them.

  The spread of shrubs carries its own warming effect. In winter, shrub branches protrude through snow cover, breaking up what would otherwise be a uniform reflective surface. This disrupted snow cover has a lower albedo than undisturbed snow, with reductions of up to 55%. Lower albedo means more solar radiation is absorbed rather than reflected, pushing surface temperatures higher and affecting the thermal stability of permafrost beneath.

  Carbon cycling is shifting alongside vegetation. As parts of the tundra take on more shrub cover, they begin to behave more like boreal forests. Warmer temperatures accelerate permafrost thawing and carbon release, while plants with increased growth capture more carbon. Studies suggest this balance is more likely than not to tip toward net carbon increase in the atmosphere over time. North American boreal forests showed a more complex picture, with some regions actually browning during the study period, influenced by droughts, fire, animal behavior, and industrial pollution.

• 5. Fauna Under Pressure

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  In July 2019, 200 Svalbard reindeer were found starved to death, a loss attributed to low precipitation linked to climate change. That episode was one chapter in the long-term decline of the species. United States Geological Survey research has projected that shrinking sea ice would eventually extirpate polar bears from Alaska, while some habitat in the Canadian Arctic Archipelago and along the northern Greenland coast might remain.

  Beavers have been actively moving north. As they build dams, they flood areas that were previously permafrost, accelerating its thaw and increasing methane emissions from the waterlogged ground. Colonizing species from the south can displace native Arctic species, and interbreeding also occurs, as with the grizzly-polar bear hybrid. The usual consequence is a reduction in genetic diversity within the genus. Infectious diseases including brucellosis and phocine distemper virus may spread to populations previously separated by cold or sea ice.

  The marine system is also under strain. Atlantic cod have been able to push deeper into the Arctic as waters warm. Polar cod and local marine mammals have been losing habitat at the same time. Many copepod species appear to be declining, and because fish such as walleye pollock and arrowtooth flounder prey on copepods, their numbers are expected to fall as well. Around 9,000 puffins and other shorebirds in Alaska died of starvation in 2016 after too many fish moved northward beyond their reach. Ringed seals and walruses are also being negatively affected. By 2100, phytoplankton biomass in the Arctic Ocean is generally expected to increase by roughly 20% relative to 2000 under a low-emission scenario, and by 30-40% under a high-emission scenario. Marine primary production in the Arctic rose by over 30% between 1998 and 2020 as more sunlight reached phytoplankton through retreating ice.

• 6. Black Carbon and Wildfire

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  Black carbon, the fine particles produced by combustion, absorbs solar radiation and sharply reduces the reflectivity of snow and ice when it settles on them. A 2013 study found that gas flaring at petroleum extraction sites contributed over 40% of the black carbon deposited in the Arctic. Research published in 2019 attributed 56% of Arctic surface black carbon to emissions from Russia, with European and Asian emissions making up much of the remainder. That same year, a separate study concluded that black carbon emissions from Arctic shipping were on course to rise continuously, driven specifically by fishing vessels.

  2015 research suggested that cutting black carbon emissions and short-lived greenhouse gases by roughly 60% by 2050 could cool the Arctic by up to 0.2 degrees Celsius. The difficulty is that the feedback loops already in motion are making that harder to achieve. Wildfires in the Arctic Circle are becoming more frequent and more intense. In 2020, Arctic wildfire emissions set a new record, peaking at 244 megatonnes of carbon dioxide. Much of this came from burning peatlands, carbon-rich soils built up from waterlogged plants, which are disproportionately found at Arctic latitudes.

  The smoke from wildfires is classified as brown carbon. Its warming effect on the Arctic is estimated at around 30% that of black carbon. As temperatures rise, peatlands are more likely to ignite; their burning releases carbon that raises temperatures further, increasing the probability of future fires. The 2022 United Nations Environment Programme report titled "Spreading Like Wildfire" described this smoke as a contributing factor to Arctic melting through a positive feedback loop. Its authors identified the 2020 Siberian heat wave as the first extreme heat event demonstrated to have been almost impossible without anthropogenic emissions.

• 7. Geopolitics and Shipping

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  The Transpolar Sea Route, a future shipping lane running across the center of the Arctic Ocean from the Atlantic to the Pacific, largely avoids the territorial waters of Arctic states and passes through international high seas. In contrast to the Northeast Passage and the Northwest Passage, both of which hug the coastlines of specific nations, the Transpolar route cuts through waters no single country controls.

  By 2011, the Northern Sea Route had recorded 34 passages and the Northwest Passage had seen 22 traverses, more than at any previous point in history. A study on projected Arctic shipping projected remarkable shifts in trade between Asia and Europe, diversion of trade within Europe, heavy traffic in the Arctic, and a substantial drop in Suez Canal traffic. The same study noted that those trade shifts would place substantial pressure on an already threatened Arctic ecosystem.

  The retreat of sea ice has intensified competing territorial claims. The eight Arctic nations, Russia, Canada, Finland, Iceland, Norway, Sweden, the United States, and Denmark representing Greenland, are all active on the geopolitical stage. Overlapping claims in Exclusive Economic Zones are generating friction. An unclaimed triangle of international waters at the center of the region sits at the heart of multiple disputes. Both Denmark and Russia claim a large area that includes the North Pole, with parts of that claim also contested by Canada. The Northwest Passage is recognized internationally as open waters but lies technically within Canadian waters, creating an ongoing dispute with the United States over transit rights.

  Claims can be submitted to the United Nations Convention on the Law of the Sea using geological evidence that continental shelves extend beyond current maritime borders. Multiple overlapping claims remain pending resolution by international bodies. Meanwhile, the Woodwell Climate Research Center received a five-million-dollar grant from Google.org in 2023 to build an open-access satellite and machine-learning system for tracking Arctic permafrost thaw in near real-time.

• 8. Indigenous People and a Changing Land

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  Inuit communities in the Arctic are among the poorest and most unemployed populations in North America. Those existing pressures are now compounded by an environment that is transforming faster than anywhere else on Earth. Seal hunting, a major food source for many small communities, depends on sea ice flats where seals are hunted. As sea ice retreats, that foundation is shrinking.

  Migration routes for reindeer and other animals are shifting. Calving grounds and forage availability are changing. In good years, some communities are entirely sustained by the commercial harvest of specific animals. As ecological cycles grow less predictable, the disruption compounds other hardships rather than arriving in isolation.

  Researchers have documented historical and present-day trails in the Pan Inuit Trails Atlas. Changes in sea ice formation and breakup have already altered the routes that Inuit communities have used for generations. Infrastructure is threatened as well. Frozen roadways that many Arctic communities rely on for supplies and travel are becoming unreliable. Pipelines built on permafrost are at risk as the ground beneath them thaws.

  The 2016-2017 rain events near Siorapaluk that triggered mass movement and damaged archaeological sites are one concrete measure of how quickly cultural heritage is being lost. The European Space Agency launched CryoSat-2 on the 8th of April 2010 to provide satellite data on Arctic ice cover change rates, and the International Arctic Science Committee, a non-governmental organization with membership from 23 countries across three continents, continues to coordinate research across national boundaries. The 2021 AMAP report drew directly on indigenous knowledge keepers from Arctic communities alongside its scientific contributors, a recognition that the record of what is being lost exists in both data and lived memory.