Arctic haze is thephenomenon of a visible reddish-brown springtimehaze in theatmosphere at highlatitudes in theArctic due toanthropogenic[1]air pollution. A major distinguishing factor of Arctic haze is the ability of itschemical ingredients to persist in the atmosphere for significantly longer than other pollutants. Due to limited amounts ofsnow,rain, or turbulent air to displace pollutants from the polar air mass in spring, Arctic haze can linger for more than a month in thenorthern atmosphere.
Arctic haze was first noticed in 1750 when theIndustrial Revolution began. Explorers and whalers could not figure out where the foggy layer was coming from. "Poo-jok" was the term theInuit used for it.[2] Another hint towards clarifying this issue was relayed in notes approximately a century ago by Norwegian explorerFridtjof Nansen. After trekking through the Arctic he found dark stains on the ice.[3] The term "Arctic haze" was coined in 1956 byJ. Murray Mitchell, aUS Air Force officer stationed inAlaska,[4] to describe an unusual reduction in visibility observed by North American weather reconnaissance planes. From his investigations, Mitchell thought the haze had come from industrial areas in Europe and China. He went on to become an eminentclimatologist.[5]The haze is seasonal, reaching a peak in late winter and spring. When an aircraft is within a layer of Arctic haze, pilots report that horizontal visibility can drop to one tenth that of normally clear sky. At this time it was unknown whether the haze was natural or was formed by pollutants.
In 1972,Glenn Edmond Shaw attributed this smog to transboundary anthropogenic pollution, whereby the Arctic is the recipient of contaminants whose sources are thousands of miles away. Further research continues with the aim of understanding the impact of this pollution onglobal warming.[6]
Coal-burning in northern mid-latitudes contributeaerosols containing about 90%sulfur and the remaindercarbon, that makes the haze reddish in color. This pollution is helping the Arctic warm up faster than any other region, although increases ingreenhouse gases are the main driver of thisclimatic change.[7]
Sulfur aerosols in the atmosphere affect cloud formation, leading to localized cooling effects over industrialized regions due to increasedreflection of sunlight, which masks the opposite effect of trapped warmth beneath the cloud cover. During the Arctic winter, however, there is no sunlight to reflect. In the absence of this cooling effect, the dominant effect of changes to Arctic clouds is an increased trapping ofinfrared radiation from the surface.
Ship emissions,mercury,aluminium,vanadium,manganese, andaerosol andozone pollutants are many examples of the pollution that is affecting this atmosphere, but thesmoke fromforest fires is not a significant contributor.[8] Some of those pollutants figure amongenvironmental effects of coal burning. Due to low deposition rates, these pollutants are not yet having adverse effects on people or animals. Different pollutants actually represent different colors of haze. Dr. Shaw discovered in 1976 that the yellowish haze is fromdust storms inChina andMongolia. The particles were carried polewards by unusualair currents. The trapped particles were dark gray the next year he took a sample. That was caused by a heavy amount of industrial pollutants.[3]
A 2013 study found that at least 40% of theblack carbon deposited in the Arctic originated fromgas flares, predominately fromoil extraction activities throughout the northern latitudes.[9][10] The black carbon is short-lived, but suchroutine flaring also emits vast quantities of sulphur. Home fires in India also contribute.[11]
According to Tim Garrett, an assistant professor of meteorology at theUniversity of Utah involved in the study of Arctic haze at the university, mid-latitude cities contribute pollution to the Arctic, and it mixes with thin clouds, allowing them to trap heat more easily. Garrett's study found that during the darkArctic winter, when there is no precipitation to wash out pollution, the effects are strongest, because pollutants can warm the environment up to three degrees Fahrenheit.[12]
European climatologists predicted in 2009 that by the end of the 21st century, the temperature of the Arctic region is expected to rise 3°Celsius on an average day.[13] In that same article,National Geographic quoted the co-author of the study, Andreas Stohl, of theNorwegian Institute for Air Research, "Previous climate models have suggested that theArctic's summer sea ice may completely disappear by 2040 if warming continues unabated."
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