Climate change in the Arctic

Warming The period of 1995–2005 was the warmest decade in the Arctic since at least the 17th century, with temperatures above the 1951–1990 average. Alaska and western Canada's temperature rose by during that period. 2013 research has shown that temperatures in the region haven't been as high as they currently are since at least 44,000 years ago and perhaps as long as 120,000 years ago. Since 2013, Arctic annual mean surface air temperature (SAT) has been at least warmer than the 1981-2010 mean. In 2016, there were extreme anomalies from January to February with the temperature in the Arctic being estimated to be between more than it was between 1981 and 2010. In 2020, mean SAT was warmer than the 1981–2010 average. On 20 June 2020, for the first time, a temperature measurement was made inside the Arctic Circle of 38 °C, more than 100 °F. This kind of weather was expected in the region only by 2100. In March, April and May the average temperature in the Arctic was higher than normal. This heat wave, without human – induced warming, could happen only one time in 80,000 years, according to an attribution study published in July 2020. It is the strongest link of a weather event to anthropogenic climate change that had been ever found, for now. Arctic amplification Precipitation Field studies in northwest Greenland have shown that increased summer rainfall can trigger large debris flows and slope failures in permafrost terrain. In 2016–2017, unprecedented rain events near Siorapaluk caused widespread mass movement processes that reshaped the landscape and damaged archaeological sites. Approximately a quarter of the surveyed archaeological landscape was affected, providing an indicator of long-term slope stability since the late Holocene and highlighting how shifts toward rain-dominated precipitation regimes are already altering Arctic geomorphology. An observed impact of climate change is a strong increase in the number of lightnings in the Arctic. Lightnings increase the risk for wildfires. Some research suggests that globally, a warming greater than over the preindustrial level could change the type of precipitation in the Arctic from snow to rain in summer and autumn. Sea ice Greenland ice sheet Lakes A January 2025 study published in the Proceedings of the National Academy of Sciences reported an "abrupt, coherent, climate-driven transformation" from "blue" (more transparent) to "brown" (less transparent) states of lakes in Greenland after a season of both record heat and rainfall drove a state change in these systems. == Biological environment ==

Impacts on Arctic flora Climate change is expected to have a strong effect on the Arctic's flora, some of which is already being seen. NASA and NOAA have continuously monitored Arctic vegetation with satellite instruments such as Moderate Resolution Imaging Spectroradiometer (MODIS) and Advanced Very-High-Resolution Radiometer (AVHRR). Their data allows scientists to calculate so-called "Arctic greening" and "Arctic browning". From 1985 to 2016, greening has occurred in 37.3% of all sites sampled in the tundra, whereas browning was observed only in 4.7% of the sites - typically the ones that were still experiencing cooling and drying, as opposed to warming and wettening for the rest. This expansion of vegetation in the Arctic is not equivalent across types of vegetation. A major trend has been from shrub-type plants taking over areas previously dominated by moss and lichens. This change contributes to the consideration that the tundra biome is currently experiencing the most rapid change of any terrestrial biomes on the planet. The direct impact on mosses and lichens is unclear as there exist very few studies at species level, but climate change is more likely to cause increased fluctuation and more frequent extreme events. While shrubs may increase in range and biomass, warming may also cause a decline in cushion plants such as moss campion, and since cushion plants act as facilitator species across trophic levels and fill important ecological niches in several environments, this could cause cascading effects in these ecosystems that could severely affect the way in which they function and are structured. The expansion of these shrubs can also have strong effects on other important ecological dynamics, such as the albedo effect. These shrubs change the winter surface of the tundra from undisturbed, uniform snow to mixed surface with protruding branches disrupting the snow cover, this type of snow cover has a lower albedo effect, with reductions of up to 55%, which contributes to a positive feedback loop on regional and global climate warming. This is speeding up the carbon cycle, as warmer temperatures lead to increased permafrost thawing and carbon release, but also carbon capturing from plants that have increased growth. In North America, some boreal forests actually experienced browning over the study period. Droughts, increased forest fire activity, animal behavior, industrial pollution, and a number of other factors may have contributed to browning. --> Impacts on terrestrial fauna Arctic warming negatively affects the foraging and breeding ecology of native Arctic mammals, such as Arctic foxes or Arctic reindeer. In July 2019, 200 Svalbard reindeer were found starved to death apparently due to low precipitation related to climate change. This was only one episode in the long-term decline of the species. As the pure Arctic climate is gradually replaced by the subarctic climate, animals adapted to those conditions spread to the north. These colonizing species can outright replace native species, and they may also interbreed with their southern relations, like in the case of the Grizzly–polar bear hybrid. This usually has the effect of reducing the genetic diversity of the genus. Infectious diseases, such as brucellosis or phocine distemper virus, may spread to populations previously separated by the cold, or, in case of the marine mammals, the sea ice. Marine ecosystems The reduction of sea ice has brought more sunlight to the phytoplankton and increased the annual marine primary production in the Arctic by over 30% between 1998 and 2020. yet, it still accounts for only 5% to 14% of the total ocean carbon sink, although it is expected to play a larger role in the future. By 2100, phytoplankton biomass in the Arctic Ocean is generally expected to increase by ~20% relative to 2000 under the low-emission scenario, and by 30-40% under the high-emission scenario. While the shorebirds also appear to nest more successfully due to the observed warming, this benefit may be more than offset by phenological mismatch between shorebirds' and other species' life cycles. Marine mammals such as ringed seals and walruses are also being negatively affected by the warming. == Greenhouse gas emissions from the Arctic ==

In 2024, the Arctic has transformed from a carbon sink to a carbon source due to the impacts of climate change, mainly rising temperatures and wildfires. Permafrost thaw Permafrost is an important component of hydrological systems and ecosystems within the Arctic landscape. In the Northern Hemisphere the terrestrial permafrost domain comprises around 18 million km2. Within this permafrost region, the total soil organic carbon (SOC) stock is estimated to be 1,460-1,600 Pg (where 1 Pg = 1 billion tons), which constitutes double the amount of carbon currently contained in the atmosphere. In 2023, Woodwell Climate Research Center received a $5 million grant and fellowship from Google.org, the philanthropic arm of Google, to develop an open-access resource that will use satellite data and artificial intelligence in order to track Arctic permafrost thaw in near real-time. Black carbon Black carbon deposits (from the combustion of heavy fuel oil (HFO) of Arctic shipping) absorb solar radiation in the atmosphere and strongly reduce the albedo when deposited on snow and ice, thus accelerating the effect of the melting of snow and sea ice. A 2013 study quantified that gas flaring at petroleum extraction sites contributed over 40% of the black carbon deposited in the Arctic. 2019 research attributed the majority (56%) of Arctic surface black carbon to emissions from Russia, followed by European emissions, and Asia also being a large source. However, a 2019 study indicates that "Black carbon emissions will continuously rise due to increased shipping activities", specifically fishing vessels. The number of wildfires in the Arctic Circle has increased. In 2020, Arctic wildfire emissions broke a new record, peaking at 244 megatonnes of carbon dioxide emitted. This is due to the burning of peatlands, carbon-rich soils that originate from the accumulation of waterlogged plants which are mostly found at Arctic latitudes. These peatlands are becoming more likely to burn as temperatures increase, but their own burning and releasing of contributes to their own likelihood of burning in a positive feedback loop. The smoke from wildfires defined as "brown carbon" also increases arctic warming, with its warming effect is around 30% that of black carbon. As wildfires increases with warming this creates a positive feedback loop. Methane clathrate deposits ==Effects on other parts of the world==

On ocean circulation in this scenario (middle). The collapse of the entire Atlantic Meriditional Overturning Circulation (bottom). On mid-latitude weather == Impacts on people ==

Territorial claims Growing evidence that global warming is shrinking polar ice has added to the urgency of several nations' Arctic territorial claims in hopes of establishing resource development and new shipping lanes, in addition to protecting sovereign rights. As ice sea coverage decreases more and more, year on year, Arctic countries (Russia, Canada, Finland, Iceland, Norway, Sweden, the United States and Denmark representing Greenland) are making moves on the geopolitical stage to ensure access to potential new shipping lanes, oil and gas reserves, leading to overlapping claims across the region. There is more activity in terms of maritime boundaries between countries, where overlapping claims for internal waters, territorial seas and particularly Exclusive Economic Zones (EEZs) can cause frictions between nations. Currently, official maritime borders have an unclaimed triangle of international waters lying between them, that is at the centerpoint of international disputes. Governments and private industry have shown a growing interest in the Arctic. Major new shipping lanes are opening up: the northern sea route had 34 passages in 2011 while the Northwest Passage had 22 traverses, more than any time in history. Shipping companies may benefit from the shortened distance of these northern routes. Access to natural resources will increase, including valuable minerals and offshore oil and gas. Infrastructure Toxic pollution Impacts on indigenous peoples As climate change speeds up, it is having more and more of a direct impact on societies around the world. This is particularly true of people that live in the Arctic, where increases in temperature are occurring at faster rates than at other latitudes in the world, and where traditional ways of living, deeply connected with the natural arctic environment are at particular risk of environmental disruption caused by these changes. The warming of the atmosphere and ecological changes that come alongside it presents challenges to local communities such as the Inuit. Hunting, which is a major way of survival for some small communities, will be changed with increasing temperatures. The reduction of sea ice will cause certain species populations to decline or even become extinct. Unsuspected changes in river and snow conditions will cause herds of animals, including reindeer, to change migration patterns, calving grounds, and forage availability. Researchers have documented historical and current trails created by the Inuit in the Pan Inuit Trails Atlas, finding that the change in sea ice formation and breakup has resulted in changes to the routes of trails created by the Inuit. == Adaptation ==

Research Individual countries within the Arctic zone, Canada, Denmark (Greenland), Finland, Iceland, Norway, Russia, Sweden, and the United States (Alaska) conduct independent research through a variety of organizations and agencies, public and private, such as Russia's Arctic and Antarctic Research Institute. Countries who do not have Arctic claims, but are close neighbors, conduct Arctic research as well, such as the Chinese Arctic and Antarctic Administration (CAA). The United States's National Oceanic and Atmospheric Administration (NOAA) produces an Arctic Report Card annually, containing peer-reviewed information on recent observations of environmental conditions in the Arctic relative to historical records. • International Arctic Buoy Program: deploys and maintains buoys that provide real-time position, pressure, temperature, and interpolated ice velocity data • International Arctic Research Center: Main participants are the United States and Japan. • International Arctic Science Committee: non-governmental organization (NGO) with diverse membership, including 23 countries from 3 continents. • 'Role of the Arctic Region', in conjunction with the International Polar Year, was the focus of the second international conference on Global Change Research, held in Nynäshamn, Sweden, October 2007. • SEARCH (Study of Environmental Arctic Change): A research framework originally promoted by several US agencies; an international extension is ISAC (the International Study of Arctic Change). The 2021 Arctic Monitoring and Assessment Programme (AMAP) report by an international team of more than 60 experts, scientists, and indigenous knowledge keepers from Arctic communities, was prepared from 2019 to 2021. It is a follow-up report of the 2017 assessment, "Snow, Water, Ice and Permafrost in the Arctic" (SWIPA). According to an 11 August 2022 article published in Nature, there have been numerous reports that the Arctic is warming from twice to three times as fast as the global average since 1979, but the co-authors cautioned that the recent report of the "four-fold Arctic warming ratio" was potentially an "extremely unlikely event". The 14 December 2021 16th Arctic Report Card produced by the United States's National Oceanic and Atmospheric Administration (NOAA) and released annually, examined the "interconnected physical, ecological and human components" of the circumpolar Arctic. The report said that the 12 months between October 2020 and September 2021 were the "seventh warmest over Arctic land since the record began in 1900". NOAA's State of the Arctic Reports, starting in 2006, updates some of the records of the original 2004 and 2005 Arctic Climate Impact Assessment (ACIA) reports by the intergovernmental Arctic Council and the non-governmental International Arctic Science Committee. A 2022 United Nations Environment Programme (UNEP) report "Spreading Like Wildfire: The Rising Threat Of Extraordinary Landscape Fires" said that smoke from wildfires around the world created a positive feedback loop that is a contributing factor to Arctic melting. The 2020 Siberian heatwave was "associated with extensive burning in the Arctic Circle". ==See also==