Rotten ice is a loose term for ice that is melting or structurally disintegrating due to being honeycombed [1] by liquid water, air, or contaminants trapped between the initial growth of ice crystals. It may appear transparent or splotchy grey, and it is generally found after spring or summer thaws, presenting a danger to those traveling or spending time in outdoor recreation. The increase of rotten ice vs. solid ice in the Arctic affects ocean-atmosphere heat transfer and year-to-year ice formation, as well as the lives of the Inuit, sea mammals such as walrus and polar bear, and the microorganisms that live inside the ice.
Rotten ice has a subtype called "candle ice", which has a columnar structure. Like other rotten ice, it poses a hazard to humans due to its lack of structure.
Compared to solid ice, rotten ice has "high porosity and enhanced permeability." [2] This porosity facilitates "large convective transport of nutrients, salt and heat at the onset of fall freeze-up," which Algal bloom may also contribute. [3] It forms on open water when snowpack and ice are mixed together[ citation needed ] or when polar ice melts during the spring [4] or summer. [5] If saturated with water, rotten ice may look dark or transparent, similar to new black ice, [1] but otherwise it may look grey and splotchy. [6] Though rotten ice may appear strong, it is weak—even several feet thick may not hold a person's weight. On land, it is difficult or impossible to climb.[ citation needed ]
Rotting may begin at the top or bottom surface and occurs due to absorption of heat from the sun. [6] In general, ice melting may accelerate due to various factors. Water from underneath the ice can erode the ice and cause it to be thinner without a sign on the surface. Runoff from upstream melting, roads (especially salted), and snow can weaken the ice, and "tree stumps, rocks and docks absorb heat from the sun, causing ice around them to melt." [7] Ice may melt faster along shorelines. Ice under a layer of snow will be thinner and weaker due to the snow's insulating effect; a new snowfall can also warm up and melt existing ice. [7] However, snow or snow ice may also absorb or reflect incoming solar radiation and prevent rotting until the snow is melted. [6] Regardless of thickness, ice will be weakened by multiple freezes and thaws or layers of snow inside the ice itself. [7] It melts more quickly than solid ice. [8]
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 a stabilizing effect to the ice. [9] However, other scientists have found algae and other microorganisms produce pigments or help create a substance, cryoconite, all of which increase rotting and further the growth of the microorganisms. [3] [10]
In 2009, researchers studying the Beaufort Sea north of Alaska found that most of the ice present had become rotten ice, instead of thick, solid ice that had either been newly formed or present for multiple years. This decline in multiyear ice contradicted previous impressions that Arctic ice was recovering from climate change and "had implications for climate science and marine vessel transport in the Arctic." [11] Other research has found that the increased permeability of rotten ice can "contribute to ocean–atmosphere heat transfer." [2] Future increases of rotten ice matter influence long-term ice cover: "If the ice melts completely, then the open ocean will form new ice in the autumn. Only ice remaining at the end of summer can become second-year and subsequently multiyear ice." [2] As rotten ice exposes more of the ocean, it also creates a feedback loop where the exposed darker ocean absorbs more heat, which melts more ice and exposes more ocean. [8]
In the years leading up to 2015, Greenland's ice cover has decreased to "a rotten ice regime", with months of solid ice decreasing from 9 per year to 2-3, and with thickness decreasing from 6-10 feet to 7 inches by 2004. [5] The decline of solid land ice to rotten ice strongly disrupts travel and subsistence hunting for the local Inuit, as well as travel and habitat for sea mammals. [5] In the future, the shedding rotted or melted ice may affect coastlines of other continents via rising sea levels. [8]
Candle ice (sometimes known as needle ice) [12] is a form of rotten ice that develops in columns perpendicular to the surface of a lake or other body of water. [13] It makes a clinking sound when the "candles" are broken apart and floating in the water, bumping up against each other. [14] As ice from a larger surface melts, the formation of candle ice "progressively increases with time, temperature, and quantity of water melt runoff." [15] This occurs due to the hexagonal structure of the ice crystals; minerals such as salt, as well as other contaminants, can be trapped between the crystals when they initially form, and melting will begin at these boundaries due to the trapped contaminants. [16] No matter the thickness, [4] it can be dangerous due to its lack of horizontal structure, which means there will be no rim to grab for any person who falls through. [17]
A glacier is a persistent body of dense ice that is constantly moving under its own weight. A glacier forms where the accumulation of snow exceeds its ablation over many years, often centuries. It acquires distinguishing features, such as crevasses and seracs, as it slowly flows and deforms under stresses induced by its weight. As it moves, it abrades rock and debris from its substrate to create landforms such as cirques, moraines, or fjords. Although a glacier may flow into a body of water, it forms only on land and is distinct from the much thinner sea ice and lake ice that form on the surface of bodies of water.
The cryosphere is an all-encompassing term for the portions of Earth's surface where water is in solid form, including sea ice, lake ice, river ice, snow cover, glaciers, ice caps, ice sheets, and frozen ground. Thus, there is a wide overlap with the hydrosphere. The cryosphere is an integral part of the global climate system with important linkages and feedbacks generated through its influence on surface energy and moisture fluxes, clouds, precipitation, hydrology, atmospheric and oceanic circulation.
Sea ice arises as seawater freezes. Because ice is less dense than water, it floats on the ocean's surface. Sea ice covers about 7% of the Earth's surface and about 12% of the world's oceans. Much of the world's sea ice is enclosed within the polar ice packs in the Earth's polar regions: the Arctic ice pack of the Arctic Ocean and the Antarctic ice pack of the Southern Ocean. Polar packs undergo a significant yearly cycling in surface extent, a natural process upon which depends the Arctic ecology, including the ocean's ecosystems. Due to the action of winds, currents and temperature fluctuations, sea ice is very dynamic, leading to a wide variety of ice types and features. Sea ice may be contrasted with icebergs, which are chunks of ice shelves or glaciers that calve into the ocean. Depending on location, sea ice expanses may also incorporate icebergs.
An ice shelf is a large floating platform of ice that forms where a glacier or ice sheet flows down to a coastline and onto the ocean surface. Ice shelves are only found in Antarctica, Greenland, Northern Canada, and the Russian Arctic. The boundary between the floating ice shelf and the anchor ice that feeds it is the grounding line. The thickness of ice shelves can range from about 100 m (330 ft) to 1,000 m (3,300 ft).
In glaciology, an ice sheet, also known as a continental glacier, is a mass of glacial ice that covers surrounding terrain and is greater than 50,000 km2 (19,000 sq mi). The only current ice sheets are in Antarctica and Greenland; during the Last Glacial Period at Last Glacial Maximum, the Laurentide Ice Sheet covered much of North America, the Weichselian ice sheet covered Northern Europe and the Patagonian Ice Sheet covered southern South America.
The Byrd Polar and Climate Research Center (BPCRC) is a polar, alpine, and climate research center at The Ohio State University founded in 1960.
A polar ice cap or polar cap is a high-latitude region of a planet, dwarf planet, or natural satellite that is covered in ice.
The Greenland ice sheet is a vast body of ice covering 1,710,000 square kilometres (660,000 sq mi), roughly near 80% of the surface of Greenland. It is sometimes referred to as an ice cap, or under the term inland ice, or its Danish equivalent, indlandsis. The acronym GIS is frequently used in the scientific literature.
Ice algae are any of the various types of algal communities found in annual and multi-year sea, and terrestrial lake ice or glacier ice.
Meltwater is water released by the melting of snow or ice, including glacial ice, tabular icebergs and ice shelves over oceans. Meltwater is often found during early spring when snow packs and frozen rivers melt with rising temperatures, and in the ablation zone of glaciers where the rate of snow cover is reducing. Meltwater can be produced during volcanic eruptions, in a similar way in which the more dangerous lahars form.
Camp Century was an Arctic United States military scientific research base in Greenland. situated 240 km (150 mi) east of Pituffik Space Base. When built, Camp Century was publicized as a demonstration for affordable ice-cap military outposts and a base for scientific research.
The climate of the Arctic is characterized by long, cold winters and short, cool summers. There is a large amount of variability in climate across the Arctic, but all regions experience extremes of solar radiation in both summer and winter. Some parts of the Arctic are covered by ice year-round, and nearly all parts of the Arctic experience long periods with some form of ice on the surface.
The Arctic Ocean is the smallest and shallowest of the world's five major oceans. It spans an area of approximately 14,060,000 km2 (5,430,000 sq mi) and is known as one of the coldest of oceans. The International Hydrographic Organization (IHO) recognizes it as an ocean, although some oceanographers call it the Arctic Mediterranean Sea. It has also been described as an estuary of the Atlantic Ocean. It is also seen as the northernmost part of the all-encompassing World Ocean.
Arctic geoengineering is a type of climate engineering in which polar climate systems are intentionally manipulated to reduce the undesired impacts of climate change. As a proposed solution to climate change, arctic geoengineering is relatively new and has not been implemented on a large scale. It is based on the principle that Arctic albedo plays a significant role in regulating the Earth's temperature and that there are large-scale engineering solutions that can help maintain Earth's hemispheric albedo. According to researchers, projections of sea ice loss, when adjusted to account for recent rapid Arctic shrinkage, indicate that the Arctic will likely be free of summer sea ice sometime between 2059 and 2078. Advocates for Arctic geoengineering believe that climate engineering methods can be used to prevent this from happening.
Measurement of sea ice is important for safety of navigation and for monitoring the environment, particularly the climate. Sea ice extent interacts with large climate patterns such as the North Atlantic oscillation and Atlantic Multidecadal Oscillation, to name just two, and influences climate in the rest of the globe.
The North American Arctic is composed of the northern polar regions of Alaska (USA), Northern Canada and Greenland. Major bodies of water include the Arctic Ocean, Hudson Bay, the Gulf of Alaska and North Atlantic Ocean. The North American Arctic lies above the Arctic Circle. It is part of the Arctic, which is the northernmost region on Earth. The western limit is the Seward Peninsula and the Bering Strait. The southern limit is the Arctic Circle latitude of 66° 33’N, which is the approximate limit of the midnight sun and the polar night.
The Surface Heat Budget of the Arctic Ocean (SHEBA) study was a National Science Foundation-funded research project designed to quantify the heat transfer processes that occur between the ocean and the atmosphere over the course of a year in the Arctic Ocean, where the sun is above the horizon from spring through summer and below the horizon the rest of the time. The study was designed to provide data for use in global climate models, which scientists use to study global climate change.
In earth science, global surface temperature is calculated by averaging the temperatures over sea and land. Periods of global cooling and global warming have alternated throughout Earth's history.
Sea ice in the Arctic has declined in recent decades in area and volume due to climate change. It has been melting more in summer than it refreezes in winter. Global warming, caused by greenhouse gas forcing is responsible for the decline in Arctic sea ice. The decline of sea ice in the Arctic has been accelerating during the early twenty‐first century, with a decline rate of 4.7% per decade. It is also thought that summertime sea ice will cease to exist sometime during the 21st century.
The Arctic ice pack is the sea ice cover of the Arctic Ocean and its vicinity. The Arctic ice pack undergoes a regular seasonal cycle in which ice melts in spring and summer, reaches a minimum around mid-September, then increases during fall and winter. Summer ice cover in the Arctic is about 50% of winter cover. Some of the ice survives from one year to the next. Currently, 28% of Arctic basin sea ice is multi-year ice, thicker than seasonal ice: up to 3–4 m (9.8–13.1 ft) thick over large areas, with ridges up to 20 m (65.6 ft) thick. Besides the regular seasonal cycle there has been an underlying trend of declining sea ice in the Arctic in recent decades as well.