Misplaced Pages

#205794

90-604: The Arctic ( / ˈ ɑːr k t ɪ k / or / ˈ ɑːr t ɪ k / ) (from Greek ἄρκτος, 'bear') is a polar region located at the northernmost part of Earth. The Arctic region, from the IERS Reference Meridian travelling east, consists of parts of northern Norway ( Nordland , Troms , Finnmark , Svalbard and Jan Mayen ), northernmost Sweden ( Västerbotten , Norrbotten and Lappland ), northern Finland ( North Ostrobothnia , Kainuu and Lappi ), Russia ( Murmansk , Siberia , Nenets Okrug , Novaya Zemlya ),

180-714: A Russian flag made of rust-proof titanium alloy . The flag-placing, during Arktika 2007 , generated commentary on and concern for a race for control of the Arctic's vast hydrocarbon resources. Foreign ministers and other officials representing Canada, the Kingdom of Denmark, Norway, Russia, and the United States met in Ilulissat, Greenland on 28 May 2008 at the Arctic Ocean Conference and announced

270-513: A ring species exists and has been described around the Arctic Circle in the form of the Larus gulls. There are copious natural resources in the Arctic (oil, gas, minerals, fresh water, fish and, if the subarctic is included, forest) to which modern technology and the economic opening up of Russia have given significant new opportunities. The interest of the tourism industry is also on

360-681: A 2019 paper holds BKS ice decline responsible for 44% of the 1995–2014 central Eurasian cooling trend, far more than indicated by the models, while another study from that year suggests that the decline in BKS ice reduces snow cover in the North Eurasia but increases it in central Europe. There are also potential links to summer precipitation: a connection has been proposed between the reduced BKS ice extent in November–December and greater June rainfall over South China . One paper even identified

450-696: A connection between Kara Sea ice extent and the ice cover of Lake Qinghai on the Tibetan Plateau . However, BKS ice research is often subject to the same uncertainty as the broader research into Arctic amplification/whole-Arctic sea ice loss and the jet stream, and is often challenged by the same data. Nevertheless, the most recent research still finds connections which are statistically robust, yet non-linear in nature: two separate studies published in 2021 indicate that while autumn BKS ice loss results in cooler Eurasian winters, ice loss during winter makes Eurasian winters warmer: as BKS ice loss accelerates,

540-521: A consequence of melting glaciers and other ice in Greenland, could soon contribute to a substantial rise in sea levels worldwide. The current Arctic warming is leading to ancient carbon being released from thawing permafrost , leading to methane and carbon dioxide production by micro-organisms. Release of methane and carbon dioxide stored in permafrost could cause abrupt and severe global warming, as they are potent greenhouse gases . Climate change

630-464: A few decades. The amount of multi-year sea ice in the Arctic has declined considerably in recent decades. In 1988, ice that was at least 4 years old accounted for 26% of the Arctic's sea ice. By 2013, ice that age was only 7% of all Arctic sea ice. Scientists recently measured sixteen-foot (five-meter) wave heights during a storm in the Beaufort Sea in mid-August until late October 2012. This

720-488: A global warming of 1.5 degrees Celsius, but once in every 8 years under 2 degrees and once in every 1.5 years under 3 degrees. Very high levels of global warming could eventually prevent Arctic sea ice from reforming during the Arctic winter. This is known as an ice-free winter, and it ultimately amounts to a total of loss of Arctic ice throughout the year. A 2022 assessment found that unlike an ice-free summer, it may represent an irreversible tipping point. It estimated that it

810-465: A larger area, being less concentrated, and also travels a longer distance through the Earth's atmosphere in which it may be absorbed, scattered or reflected, which is the same thing that causes winters to be colder than the rest of the year except in tropical regions. The axial tilt of the Earth has the most effect on climate of the polar regions due to its latitude. However, since the polar regions are

900-705: A nearly ice-free Arctic in the summer by the 2030s. In 2021, the IPCC Sixth Assessment Report assessed that there is "high confidence" that the Arctic Ocean will likely become practically ice-free in September before the year 2050 under all SSP scenarios . A paper published in 2021 shows that the CMIP6 models which perform the best at simulating Arcic sea ice trends project the first ice-free conditions around 2035 under SSP5-8.5, which

990-556: A number of definitions of what area is contained within the Arctic. The area can be defined as north of the Arctic Circle (about 66° 34'N), the approximate southern limit of the midnight sun and the polar night . Another definition of the Arctic, which is popular with ecologists , is the region in the Northern Hemisphere where the average temperature for the warmest month (July) is below 10 °C (50 °F);

SECTION 10

#1732766253206

1080-446: A result, they have less time to hunt their historically preferred prey of seal pups, and must spend more time on land and hunt other animals. As a result, the diet is less nutritional, which leads to reduced body size and reproduction, thus indicating population decline in polar bears. The Arctic refuge is where polar bears main habitat is to den and the melting arctic sea ice is causing a loss of species. There are only about 900 bears in

1170-680: A result, this will lead to an undesirable effect on terrestrial ecosystems and put marine species at risk. Sea ice decline has been linked to boreal forest decline in North America and is assumed to culminate with an intensifying wildfire regime in this region. The annual net primary production of the Eastern Bering Sea was enhanced by 40–50% through phytoplankton blooms during warm years of early sea ice retreat. Polar bears are turning to alternative food sources because Arctic sea ice melts earlier and freezes later each year. As

1260-410: A true ice-free summer during the winter, and if the next Arctic summer is less warm, it may avoid another ice-free episode until another similarly warm year down the line. However, higher levels of global warming would delay the recovery from ice-free episodes and make them occur more often and earlier in the summer. A 2018 paper estimated that an ice-free September would occur once in every 40 years under

1350-586: A type of marine Crustacea , which in turn feed a complex of living creatures from penguins to blue whales . Arctic sea ice decline The region is at its warmest in at least 4,000 years. Furthermore, the Arctic-wide melt season has lengthened at a rate of five days per decade (from 1979 to 2013), dominated by a later autumn freeze-up. The IPCC Sixth Assessment Report (2021) stated that Arctic sea ice area will likely drop below 1 million km in at least some Septembers before 2050. In September 2020,

1440-460: Is a large variance in predictions of Arctic sea ice loss, with models showing near-complete to complete loss in September from 2035 to some time around 2067. Arctic life is characterized by adaptation to short growing seasons with long periods of sunlight, and cold, dark, snow-covered winter conditions. Arctic vegetation is composed of plants such as dwarf shrubs , graminoids , herbs , lichens , and mosses , which all grow relatively close to

1530-438: Is a new phenomenon for the region, since a permanent sea ice cover normally prevents wave formation. Wave action breaks up sea ice, and thus could become a feedback mechanism, driving sea ice decline. For January 2016, the satellite-based data showed the lowest overall Arctic sea ice extent of any January since records began in 1979. Bob Henson from Wunderground noted: Hand in hand with the skimpy ice cover, temperatures across

1620-519: Is a unique area among Earth's ecosystems. The cultures in the region and the Arctic indigenous peoples have adapted to its cold and extreme conditions. Life in the Arctic includes zooplankton and phytoplankton , fish and marine mammals , birds, land animals, plants and human societies. Arctic land is bordered by the subarctic . The word Arctic comes from the Greek word ἀρκτικός ( arktikos ), "near

1710-677: Is also claiming a large swath of seabed along the Lomonosov Ridge but, unlike Denmark, confined its claim to its side of the Arctic region. In August 2015, Russia made a supplementary submission for the expansion of the external borders of its continental shelf in the Arctic Ocean , asserting that the eastern part of the Lomonosov Ridge and the Mendeleyev Ridge are an extension of the Eurasian continent. In August 2016,

1800-484: Is also predicted to have a large impact on tundra vegetation, causing an increase of shrubs, and having a negative impact on bryophytes and lichens. Apart from concerns regarding the detrimental effects of warming in the Arctic, some potential opportunities have gained attention. The melting of the ice is making the Northwest Passage , shipping routes through the northernmost latitudes, more navigable, raising

1890-483: Is equivalent to around 10% of the cumulative CO 2 increase since the start of the Industrial Revolution . When compared to the other greenhouse gases , it has had the same impact as the cumulative increase in nitrous oxide , and nearly half of the cumulative increase in methane concentrations. The effect of Arctic sea ice decline on global warming will intensify in the future as more and more ice

SECTION 20

#1732766253206

1980-403: Is linked to polar amplification. The Arctic region is especially vulnerable to the effects of any climate change , as has become apparent with the reduction of sea ice in recent years. Climate models predict much greater climate change in the Arctic than the global average, resulting in significant international attention to the region. In particular, there are concerns that Arctic shrinkage,

2070-468: Is lost. This feedback has been accounted for by all CMIP5 and CMIP6 models, and it is included in all warming projections they make, such as the estimated warming by 2100 under each Representative Concentration Pathway and Shared Socioeconomic Pathway . They are also capable of resolving the second-order effects of sea ice loss, such as the effect on lapse rate feedback, the changes in water vapor concentrations and regional cloud feedbacks. In 2021,

2160-431: Is most likely to occur at around 6.3 degrees Celsius, though it could potentially occur as early as 4.5 °C or as late as 8.7 °C. Relative to today's climate, an ice-free winter would add 0.6 degrees, with a regional warming between 0.6 and 1.2 degrees. Arctic amplification and its acceleration is strongly tied to declining Arctic sea ice: modelling studies show that strong Arctic amplification only occurs during

2250-521: Is primarily an issue in summer months. A 2007 study found the decline to be "faster than forecasted" by model simulations. A 2011 study suggested that it could be reconciled by internal variability enhancing the greenhouse gas-forced sea ice decline over the last few decades. A 2012 study, with a newer set of simulations, also projected rates of retreat that were somewhat less than that actually observed. Observation with satellites shows that Arctic sea ice area, extent, and volume have been in decline for

2340-743: Is subject to some regulatory control through the International Code for Ships Operating in Polar Waters , adopted by the International Maritime Organization on 1 January 2017 and applies to all ships in Arctic waters over 500 tonnes. Research in the Arctic has long been a collaborative international effort, evidenced by the International Polar Year . The International Arctic Science Committee , hundreds of scientists and specialists of

2430-542: Is the largest research station in Antarctica , run by the United States. Other notable stations include Palmer Station and Amundsen–Scott South Pole Station (United States), Esperanza Base and Marambio Base ( Argentina ), Scott Base ( New Zealand ), and Vostok Station (Russia). While there are no indigenous human cultures, there is a complex ecosystem, especially along Antarctica's coastal zones. Coastal upwelling provides abundant nutrients that feed krill ,

2520-496: Is the scenario of continually accelerating greenhouse gas emissions. By weighting multiple CMIP6 projections , the first year of an ice-free Arctic is likely to occur during 2040–2072 under the SSP3-7.0 scenario . Arctic sea ice maintains the cool temperature of the polar regions and it has an important albedo effect on the climate. Its bright shiny surface reflects sunlight during the Arctic summer; dark ocean surface exposed by

2610-487: Is very difficult to melt the thick ice around the Canadian Arctic Archipelago . The IPCC AR5 defines "nearly ice-free conditions" as a sea ice extent of less than 10  km for at least five consecutive years. Estimating the exact year when the Arctic Ocean will become "ice-free" is very difficult, due to the large role of interannual variability in sea ice trends. In Overland and Wang (2013),

2700-605: The Muttaburrasaurus of Australia. However, others claim that dinosaurs lived year-round at very high latitudes, such as near the Colville River , which is now at about 70° N but at the time (70 million years ago) was 10° further north. The earliest inhabitants of North America's central and eastern Arctic are referred to as the Arctic small tool tradition (AST) and existed c.  2500 BCE . AST consisted of several Paleo-Eskimo cultures, including

2790-630: The Arctic Council , and the Barents Euro-Arctic Council are more examples of collaborative international Arctic research. While there are several ongoing territorial claims in the Arctic , no country owns the geographic North Pole or the region of the Arctic Ocean surrounding it. The surrounding six Arctic states that border the Arctic Ocean—Canada, Kingdom of Denmark (with Greenland), Iceland, Norway, Russia, and

Arctic - Misplaced Pages Continue

2880-417: The Arctic Ocean pose a risk to local wildlife such as polar bears . One important aspect in understanding sea ice decline is the Arctic dipole anomaly . This phenomenon appears to have slowed down the overall loss of sea ice between 2007 and 2021, but such a trend will probably not continue. The Arctic Ocean is the mass of water positioned approximately above latitude 65° N. Arctic Sea Ice refers to

2970-667: The Arctic poppy ). Herbivores on the tundra include the Arctic hare , lemming , muskox , and reindeer (caribou). They are preyed on by the snowy owl , Arctic fox , grizzly bear , and Arctic wolf . The polar bear is also a predator, though it prefers to hunt for marine life from the ice. There are also many birds and marine species endemic to the colder regions. Other terrestrial animals include wolverines , moose , Dall sheep , ermines , and Arctic ground squirrels . Marine mammals include seals , walruses , and several species of cetacean — baleen whales and also narwhals , orcas , and belugas . An excellent and famous example of

3060-466: The IPCC Sixth Assessment Report said with high confidence that there is no hysteresis and no tipping point in the loss of Arctic summer sea ice. This can be explained by the increased influence of stabilizing feedback compared to the ice albedo feedback. Specifically, thinner sea ice leads to increased heat loss in the winter, creating a negative feedback loop. This counteracts the positive ice albedo feedback . As such, sea ice would recover even from

3150-622: The Ilulissat Declaration , blocking any "new comprehensive international legal regime to govern the Arctic Ocean," and pledging "the orderly settlement of any possible overlapping claims." As of 2012, the Kingdom of Denmark is claiming the continental shelf based on the Lomonosov Ridge between Greenland and over the North Pole to the northern limit of the exclusive economic zone of Russia . The Russian Federation

3240-614: The Independence cultures and Pre-Dorset culture. The Dorset culture ( Inuktitut : Tuniit or Tunit ) refers to the next inhabitants of central and eastern Arctic. The Dorset culture evolved because of technological and economic changes during the period of 1050–550 BCE. With the exception of the Quebec / Labrador peninsula, the Dorset culture vanished around 1500 CE. Supported by genetic testing , evidence shows that descendants of

3330-849: The UN Commission on the Limits of the Continental Shelf began to consider Russia's submission. Canada claims the Northwest Passage as part of its internal waters belonging to Canada, while the United States and most maritime nations regards it as an international strait , which means that foreign vessels have right of transit passage. Since 1937, the larger portion of the Asian-side Arctic region has been extensively explored by Soviet and Russian crewed drifting ice stations . Between 1937 and 1991, 88 international polar crews established and occupied scientific settlements on

3420-632: The United States ( Alaska ), Canada ( Yukon , the Northwest Territories and Nunavut ), Denmark ( Greenland ), Norway , Finland , Sweden , Iceland , and Russia . Arctic circumpolar populations, though small, often share more in common with each other than with other populations within their national boundaries. As such, the northern polar region is diverse in human settlements and cultures. The southern polar region has no permanent human habitation as of now. McMurdo Station

3510-429: The drift ice and were carried thousands of kilometres by the ice flow. The Arctic is comparatively clean, although there are certain ecologically difficult localized pollution problems that present a serious threat to people's health living around these pollution sources. Due to the prevailing worldwide sea and air currents, the Arctic area is the fallout region for long-range transport pollutants , and in some places

3600-420: The permafrost thaws. The melting of Greenland's ice sheet is linked to polar amplification . Due to the poleward migration of the planet's isotherms (about 56 km (35 mi) per decade during the past 30 years as a consequence of global warming), the Arctic region (as defined by tree line and temperature) is currently shrinking. Perhaps the most alarming result of this is Arctic sea ice shrinkage. There

3690-553: The Antarctic and its contribution to sea level rise is instead driven entirely by the warming of the Southern Ocean , which had absorbed 35–43% of the total heat taken up by all oceans between 1970 and 2017. Barents Sea is the fastest-warming part of the Arctic, and some assessments now treat Barents sea ice as a separate tipping point from the rest of the Arctic sea ice, suggesting that it could permanently disappear once

Arctic - Misplaced Pages Continue

3780-476: The Arctic have been extraordinarily warm for midwinter. Just before New Year's, a slug of mild air pushed temperatures above freezing to within 200 miles of the North Pole. That warm pulse quickly dissipated, but it was followed by a series of intense North Atlantic cyclones that sent very mild air poleward, in tandem with a strongly negative Arctic oscillation during the first three weeks of the month. January 2016's remarkable phase transition of Arctic oscillation

3870-458: The Arctic include rising temperatures, loss of sea ice , and melting of the Greenland ice sheet . Potential methane release from the region, especially through the thawing of permafrost and methane clathrates , is also a concern. Because of the amplified response of the Arctic to global warming, it is often seen as a leading indicator of global warming. The melting of Greenland's ice sheet

3960-457: The Arctic refuge national conservation area. As arctic ice decays, microorganisms produce substances with various effects on melting and stability. Certain types of bacteria in rotten ice pores produce polymer-like substances, which may influence the physical properties of the ice. A team from the University of Washington studying this phenomenon hypothesizes that the polymers may provide

4050-527: The Arctic will continue to rise, and so will methane emissions from northern wetlands." Cracks in Arctic sea ice expose the seawater to the air, causing mercury in the air to be absorbed into the water. This absorption leads to more mercury, a toxin, entering the food chain where it can negatively affect fish and the animals and people who consume them. Mercury is part of Earth's atmosphere due to natural causes (see mercury cycle ) and due to human emissions. Economic implications of ice-free summers and

4140-573: The Arctic, similar to the Antarctic Treaty System . The initial focus of the campaign will be a UN resolution creating a global sanctuary around the pole, and a ban on oil drilling and unsustainable fishing in the Arctic. The Arctic has climate change rates that are amongst the highest in the world. Due to the major impacts to the region from climate change the near climate future of the region will be extremely different under all scenarios of warming. The effects of climate change in

4230-470: The Bear, northern" and from the word ἄρκτος ( arktos ), meaning bear. The name refers either to the constellation known as Ursa Major , the "Great Bear", which is prominent in the northern portion of the celestial sphere , or to the constellation Ursa Minor , the "Little Bear", which contains the celestial north pole (currently very near Polaris , the current north Pole Star, or North Star). There are

4320-605: The Dorset culture, known as the Sadlermiut , survived in Aivilik, Southampton and Coats Islands , until the beginning of the 20th century. The Dorset / Thule culture transition dates around the ninth–10th centuries CE. Scientists theorize that there may have been cross-contact of the two cultures with sharing of technology, such as fashioning harpoon heads, or the Thule may have found Dorset remnants and adapted their ways with

4410-524: The Dorset people in "an example of prehistoric genocide." By 1300 CE, the Inuit , present-day Arctic inhabitants and descendants of Thule culture, had settled in west Greenland, and moved into east Greenland over the following century ( Inughuit , Kalaallit and Tunumiit are modern Greenlandic Inuit groups descended from Thule). Over time, the Inuit have migrated throughout the Arctic regions of Eastern Russia,

4500-525: The North , and Saami Council ). The council operates on consensus basis, mostly dealing with environmental treaties and not addressing boundary or resource disputes. Though Arctic policy priorities differ , every Arctic nation is concerned about sovereignty/defense, resource development, shipping routes, and environmental protection. Much work remains on regulatory agreements regarding shipping, tourism, and resource development in Arctic waters. Arctic shipping

4590-506: The US National Snow and Ice Data Center reported that the Arctic sea ice in 2020 had melted to an extent of 3.74 million km , its second-smallest extent since records began in 1979. Earth lost 28 trillion tonnes of ice between 1994 and 2017, with Arctic sea ice accounting for 7.6 trillion tonnes of this loss. The rate of ice loss has risen by 57% since the 1990s. Sea ice loss is one of the main drivers of Arctic amplification ,

SECTION 50

#1732766253206

4680-422: The United States ( Alaska ), Canada ( Yukon , Northwest Territories , Nunavut ), Danish Realm ( Greenland ), and northern Iceland ( Grímsey and Kolbeinsey ), along with the Arctic Ocean and adjacent seas. Land within the Arctic region has seasonally varying snow and ice cover, with predominantly treeless permafrost under the tundra . Arctic seas contain seasonal sea ice in many places. The Arctic region

4770-757: The United States, Canada, and Greenland. Other Circumpolar North indigenous peoples include the Chukchi , Evenks , Iñupiat , Khanty , Koryaks , Nenets , Sámi , Yukaghir , Gwichʼin , and Yupik . The eight Arctic nations (Canada, Kingdom of Denmark [Greenland & The Faroe Islands], Finland, Iceland, Norway, Sweden, Russia, and US) are all members of the Arctic Council , as are organizations representing six indigenous populations (The Aleut International Association , Arctic Athabaskan Council , Gwich'in Council International , Inuit Circumpolar Council , Russian Association of Indigenous Peoples of

4860-677: The United States—are limited to a 200 nautical miles (370 km; 230 mi) exclusive economic zone (EEZ) off their coasts. Two Arctic states (Finland and Sweden) do not have direct access to the Arctic Ocean. Upon ratification of the United Nations Convention on the Law of the Sea , a country has ten years to make claims to an extended continental shelf beyond its 200 nautical mile zone. Due to this, Norway (which ratified

4950-401: The annual minimum or maximum extent, as shown in the adjacent images. Sea ice extent is defined as the area with at least 15% of sea ice cover; it is more often used as a metric than simple total sea ice area. This metric is used to address uncertainty in distinguishing open sea water from melted water on top of solid ice, which satellite detection methods have difficulty differentiating. This

5040-483: The area of the Arctic Ocean covered by ice. The Arctic sea ice minimum is the day in a given year when Arctic sea ice reaches its smallest extent, occurring at the end of the summer melting season, normally during September. Arctic Sea ice maximum is the day of a year when Arctic sea ice reaches its largest extent near the end of the Arctic cold season, normally during March. Typical data visualizations for Arctic sea ice include average monthly measurements or graphs for

5130-511: The authors investigated three different ways of predicting future sea ice levels. They noted that the average of all models used in 2013 was decades behind the observations, and only the subset of models with the most aggressive ice loss was able to match the observations. However, the authors cautioned that there is no guarantee those models would continue to match the observations, and hence that their estimate of ice-free conditions first appearing in 2040s may still be flawed. Thus, they advocated for

5220-531: The baseline year of 2007, with the median of 28 years (i.e. around 2035). In 2009, a study using 18 CMIP3 climate models found that they project ice-free Arctic a little before 2100 under a scenario of medium future greenhouse gas emissions. In 2012, a different team used CMIP5 models and their moderate emission scenario, RCP 4.5 (which represents somewhat lower emissions than the scenario in CMIP3), and found that while their mean estimate avoids ice-free Arctic before

5310-448: The coldest recorded temperature is approximately −68 °C (−90 °F). Coastal Arctic climates are moderated by oceanic influences, having generally warmer temperatures and heavier snowfalls than the colder and drier interior areas. The Arctic is affected by current global warming , leading to climate change in the Arctic , including Arctic sea ice decline , diminished ice in the Greenland ice sheet , and Arctic methane emissions as

5400-573: The concentrations exceed the levels of densely populated urban areas. An example of this is the phenomenon of Arctic haze , which is commonly blamed on long-range pollutants. Another example is with the bioaccumulation of PCB's ( polychlorinated biphenyls ) in Arctic wildlife and people. There have been many proposals to preserve the Arctic over the years. Most recently a group of stars at the United Nations Conference on Sustainable Development , on 21 June 2012, proposed protecting

5490-507: The continent of Antarctica. The 1959 Antarctic Treaty uses the former definition. The two polar regions are distinguished from the other two climatic and biometric belts of Earth, a tropics belt near the equator, and two middle latitude regions located between the tropics and polar regions . Polar regions receive less intense solar radiation than the other parts of Earth because the Sun's energy arrives at an oblique angle , spreading over

SECTION 60

#1732766253206

5580-409: The convention in 1996), Russia (ratified in 1997), Canada (ratified in 2003) and the Kingdom of Denmark (ratified in 2004) launched projects to establish claims that certain sectors of the Arctic seabed should belong to their territories. On 2 August 2007, two Russian bathyscaphes , MIR-1 and MIR-2 , for the first time in history descended to the Arctic seabed beneath the North Pole and placed there

5670-637: The decline in Arctic ice volumes include a greater number of journeys across the Arctic Ocean Shipping lanes during the year. This number has grown from 0 in 1979 to 400–500 along the Bering strait and >40 along the Northern Sea Route in 2013. Traffic through the Arctic Ocean is likely to increase further. An early study by James Hansen and colleagues suggested in 1981 that a warming of 5 to 10 °C, which they expected as

5760-465: The end of the century, ice-free conditions in 2045 were within one standard deviation of the mean. In 2013, a study compared projections from the best-performing subset of CMIP5 models with the output from all 30 models after it was constrained by the historical ice conditions, and found good agreement between these approaches. Altogether, it projected ice-free September between 2054 and 2058 under RCP 8.5, while under RCP 4.5, Arctic ice gets very close to

5850-462: The farthest from the equator , they receive the weakest solar radiation and are therefore generally frigid year round due to the earth's axial tilt of 23.5° not being enough to create a high maximum midday declination to sufficiently compensate the Sun's rays for the high latitude even in summer, except for relatively brief periods in peripheral areas near the polar circles. The large amount of ice and snow also reflects and weakens of what weak sunlight

5940-907: The first ship traversed the Northern Sea Route without the use of ice-breakers. Also in 2017, the Finnish icebreaker MSV Nordica set a record for the earliest crossing of the Northwest Passage. According to the New York Times , this forebodes more shipping through the Arctic, as the sea ice melts and makes shipping easier. A 2016 report by the Copenhagen Business School found that large-scale trans-Arctic shipping will become economically viable by 2040. The decline of Arctic sea ice will provide humans with access to previously remote coastal zones. As

6030-575: The global warming exceeds 1.5 degrees. This rapid warming also makes it easier to detect any potential connections between the state of sea ice and weather conditions elsewhere than in any other area. The first study proposing a connection between floating ice decline in the Barents Sea and the neighbouring Kara Sea and more intense winters in Europe was published in 2010, and there has been extensive research into this subject since then. For instance,

6120-429: The ground, forming tundra . An example of a dwarf shrub is the bearberry . As one moves northward, the amount of warmth available for plant growth decreases considerably. In the northernmost areas, plants are at their metabolic limits, and small differences in the total amount of summer warmth make large differences in the amount of energy available for maintenance, growth and reproduction. Colder summer temperatures cause

6210-481: The ice-free threshold in 2060s, but does not cross it by the end of the century, and stays at an extent of 1.7 million km . In 2014, IPCC Fifth Assessment Report indicated a risk of ice-free summer around 2050 under the scenario of highest possible emissions. The Third U.S. National Climate Assessment (NCA), released May 6, 2014, reported that the Arctic Ocean is expected to be ice free in summer before mid-century. Models that best match historical trends project

6300-424: The increase. The Arctic contains some of the last and most extensive continuous wilderness areas in the world, and its significance in preserving biodiversity and genotypes is considerable. The increasing presence of humans fragments vital habitats. The Arctic is particularly susceptible to the abrasion of groundcover and to the disturbance of the rare breeding grounds of the animals that are characteristic to

6390-413: The melting ice absorbs more sunlight and becomes warmer, which increases the total ocean heat content and helps to drive further sea ice loss during the melting season, as well as potentially delaying its recovery during the polar night . Arctic ice decline between 1979 and 2011 is estimated to have been responsible for as much radiative forcing as a quarter of CO 2 emissions the same period, which

6480-533: The months when significant sea ice loss occurs, and that it largely disappears when the simulated ice cover is held fixed. Conversely, the high stability of ice cover in Antarctica, where the thickness of the East Antarctic ice sheet allows it to rise nearly 4 km (2.5 mi) above the sea level, means that this continent has not experienced any net warming over the past seven decades: ice loss in

6570-491: The north, and by the Antarctic ice sheet on the continent of Antarctica and the Southern Ocean in the south. The Arctic has various definitions, including the region north of the Arctic Circle (currently Epoch 2010 at 66°33'44" N), or just the region north of 60° north latitude, or the region from the North Pole south to the timberline . The Antarctic is usually defined simply as south of 60° south latitude, or

6660-462: The northernmost tree line roughly follows the isotherm at the boundary of this region. The climate of the Arctic region is characterized by cold winters and cool summers. Its precipitation mostly comes in the form of snow and is low, with most of the area receiving less than 50 cm (20 in). High winds often stir up snow, creating the illusion of continuous snowfall. Average winter temperatures can go as low as −40 °C (−40 °F), and

6750-418: The phenomenon that the Arctic warms faster than the rest of the world under climate change. It is plausible that sea ice decline also makes the jet stream weaker, which would cause more persistent and extreme weather in mid-latitudes . Shipping is more often possible in the Arctic now, and will likely increase further. Both the disappearance of sea ice and the resulting possibility of more human activity in

6840-479: The polar regions receive further, contributing to the cold. Polar regions are characterized by extremely cold temperatures, heavy glaciation wherever there is sufficient precipitation to form permanent ice , short and still cold summers, and extreme variations in daylight hours, with twenty-four hours of daylight in summer, and complete darkness at mid-winter . There are many settlements in Earth's north polar region. Countries with claims to Arctic regions are:

6930-600: The possibility that the Arctic region will become a prime trade route . One harbinger of the opening navigability of the Arctic took place in the summer of 2016 when the Crystal Serenity successfully navigated the Northwest Passage, a first for a large cruise ship. In addition, it is believed that the Arctic seabed may contain substantial oil fields which may become accessible if the ice covering them melts. These factors have led to recent international debates as to which nations can claim sovereignty or ownership over

7020-521: The predecessor culture. The evidence suggested that Inuit descend from the Birnirk of Siberia, who through the Thule culture expanded into northern Canada and Greenland, where they genetically and culturally completely replaced the Indigenous Dorset people some time after 1300 CE. The question of why the Dorset disappeared so completely has led some to suggest that Thule invaders wiped out

7110-401: The probability of cold anomalies by nearly a third. A 2015 study concluded that Arctic sea ice decline accelerates methane emissions from the Arctic tundra , with the emissions for 2005-2010 being around 1.7 million tonnes higher than they would have been with the sea ice at 1981–1990 levels. One of the researchers noted, "The expectation is that with further sea ice decline, temperatures in

7200-455: The projections from six CMIP3 climate models and estimated nearly ice-free Arctic Ocean around September 2037, with a chance it could happen as early as 2028. In 2012, this pair of researchers repeated the exercise with CMIP5 models and found that under the highest-emission scenario in CMIP5, Representative Concentration Pathway 8.5, ice-free September first occurs between 14 and 36 years after

7290-542: The range of Arctic temperature change corresponding to doubled CO 2 concentrations, could open the Northwest Passage . A 2016 study concludes that Arctic warming and sea ice decline will lead to "remarkable shifts in trade flows between Asia and Europe, diversion of trade within Europe, heavy shipping traffic in the Arctic and a substantial drop in Suez traffic. Projected shifts in trade also imply substantial pressure on an already threatened Arctic ecosystem." In August 2017,

7380-668: The region. The Arctic also holds 1/5 of the Earth's water supply. During the Cretaceous time period , the Arctic still had seasonal snows, though only a light dusting and not enough to permanently hinder plant growth. Animals such as the Chasmosaurus , Hypacrosaurus , Troodon , and Edmontosaurus may have all migrated north to take advantage of the summer growing season, and migrated south to warmer climes when winter came. A similar situation may also have been found amongst dinosaurs that lived in Antarctic regions, such as

7470-830: The risk of more severe Eurasian winter extremes diminishes while heatwave risk in the spring and summer is magnified. In 2019, it was proposed that the reduced sea ice around Greenland in autumn affects snow cover during the Eurasian winter, and this intensifies Korean summer monsoon , and indirectly affects the Indian summer monsoon. 2021 research suggested that autumn ice loss in the East Siberian Sea , Chukchi Sea and Beaufort Sea can affect spring Eurasian temperature. Autumn sea ice decline of one standard deviation in that region would reduce mean spring temperature over central Russia by nearly 0.8 °C, while increasing

7560-530: The satellite passive-microwave data indicates that from late October 1978 through the end of 1996 the extent of Arctic sea ice decreased by 2.9% per decade. Sea ice extent for the Northern Hemisphere showed a decrease of 3.8% ± 0.3% per decade from November 1978 to December 2012. An "ice-free" Arctic Ocean, sometimes referred to as a "blue ocean event" (BOE), is often defined as "having less than 1 million square kilometers of sea ice", because it

7650-432: The size, abundance, productivity and variety of plants to decrease. Trees cannot grow in the Arctic, but in its warmest parts, shrubs are common and can reach 2 m (6 ft 7 in) in height; sedges , mosses and lichens can form thick layers. In the coldest parts of the Arctic, much of the ground is bare; non-vascular plants such as lichens and mosses predominate, along with a few scattered grasses and forbs (like

7740-566: The starting assumptions about the timing and the extent of the next "big melt". Consequently, there has been a recent history of competing projections from climate models and from individual experts. A 2006 paper examined projections from the Community Climate System Model and predicted "near ice-free September conditions by 2040". A 2009 paper from Muyin Wang and James E. Overland applied observational constraints to

7830-443: The use of expert judgement in addition to models to help predict ice-free Arctic events, but they noted that expert judgement could also be done in two different ways: directly extrapolating ice loss trends (which would suggest an ice-free Arctic in 2020) or assuming a slower decline trend punctuated by the occasional "big melt" seasons (such as those of 2007 and 2012) which pushes back the date to 2028 or further into 2030s, depending on

7920-456: The waters of the Arctic. Polar regions of Earth The polar regions , also called the frigid zones or polar zones , of Earth are Earth's polar ice caps , the regions of the planet that surround its geographical poles (the North and South Poles ), lying within the polar circles . These high latitudes are dominated by floating sea ice covering much of the Arctic Ocean in

8010-413: Was 1.60 million square miles (4.153 million square kilometers). A 2018 study of the thickness of sea ice found a decrease of 66% or 2.0 m over the last six decades and a shift from permanent ice to largely seasonal ice cover. The overall trend indicated in the passive microwave record from 1978 through mid-1995 shows that the extent of Arctic sea ice is decreasing 2.7% per decade. Subsequent work with

8100-479: Was driven by a rapid tropospheric warming in the Arctic , a pattern that appears to have increased surpassing the so-called stratospheric sudden warming . The previous record of the lowest extent of the Arctic Ocean covered by ice in 2012 saw a low of 1.31 million square miles (3.387 million square kilometers). This replaced the previous record set on September 18, 2007, at 1.61 million square miles (4.16 million square kilometers). The minimum extent on 18th Sept 2019

#205794