This paper was written as part of the 2010 Alaska Oceans Sciences Bowl high school competition. The conclusions in this report are solely those of the student authors.
Upon Thin Ice
Problems Facing Barrow Alaska as a Direct Result of a Retreating and Thinning Arctic Ice Cap
The Arctic ice cap has been shrinking and thinning due to anthropogenic atmospheric changes. These changes will have drastic effects on almost every aspect of the North Slope region. Major cultural and economic changes will occur in the region because of rising sea levels and increasing water coverage. The thinning sea ice will have severe impacts on the Arctic ecosystem, having an effect on virtually every trophic-level. With changes to the atmosphere and water, come changes to the land and resources associated with it. Potential solutions to sea ice decline include increased energy efficiency in homes and businesses, artificial cultivation of algae for carbon emission sequestration, and significantly diminishing dependence on fossil fuels replacing them with algae derived bio-diesels.
The Arctic ecosystem is dependent upon ice. The arctic seas have continuous ice cycles of thawing and freezing that have been increasingly impacted by anthropogenic influences over the past few years. Such influences include, but are not limited to, the excessive use of fossil fuels, modern agricultural processes and deforestation (http://www.monthlyreview.org/). Natural events including volcanic eruptions, increased solar activity, and imperfect rotation of the earth may also contribute to changes in sea ice cycles (http://www.acoolerclimate.com/).
The growth and decline of different types of of sea ice has been changed by anthropogenic influences. There are two basic types of sea ice: multi-year and seasonal. Multi-year ice is "stiffer." There is less brine in seasonal ice and it has more air pockets. Seasonal ice, or first-year ice, is thinner, topographically uniform, and contains a substantial amount of brine (http://nsidc.org/). The multi-year sea ice is more biologically important. Algae, the base of the Arctic food web, clings to the underside of the sea ice and uses the ice to keep near the surface where the algae can receive adequate amounts of sunlight. The multi-year ice can sustain the algae better than the seasonal ice. Currently, both forms of sea ice are in decline (http://icb.oxfordjournals.org/).
In recent years, the extent of the sea ice has been reduced dramatically. According to the National Snow and Ice Data Center (NSIDC), "This year's (2009) September sea ice extent was the third lowest since the start of satellite records in 1979, and the past five years have seen the five lowest ice extents in the satellite record...Arctic sea ice is now declining at a rate of 11.2% per decade, relative to the 1979 to 2000 average" (http://nsidc.org/). These declined rates have caused the proportion of first-year ice to multi-year ice to shift. There is now, on average, a greater amount of first-year ice. The reduction of sea ice is significant because it is affecting the entirety of the arctic ecosystems. Changes in ocean-atmosphere interactions characterized by new air circulation patterns, atmospheric pressure at sea level, and high latitude storms are effecting the distribution of the seasonal and multi-year sea ice (http://archive.greenpeace.org/). The warming air melts some of the sea ice, at the same time pushing the remainder of the ice towards the central ice pack. With the ice being pushed together, because of the new ocean-atmospheric conditions, there will be more open water to absorb the suns radiation.
Warm winter winds affect the freezing and thawing cycle of the ice. Warm air, during the summer and spring, collects over the arctic cause melting of the sea ice well into the winter months. The lower air pressure along the northern Pacific causes an increase in winds, which are more detrimental to the sea ice than the current average winds. Changes in air circulation and air pressure have caused more storms in the high latitude areas, and with these storms come heavy winds, rain, and waves. Precipitation, winds, and waves have eroded shorelines and caused further sea ice decline (http://www.nytimes.com/).
The process of ice melting causes a series of positive feedback loops, which in turn warms the arctic and decreases the extent of multi-year sea ice. During the freezing process, ice traps air, including CO2. When ice melts, it releases these stored quantities of gasses, which increases the level of green house gasses in the atmosphere (http://climatechange.110mb.com/). Under the Arctic Ocean is sub-sea permafrost that acts as a lid containing vast amounts of methane trapped during the last ice age, which also increases the green house gasses (http://www.independent.co.uk/). When the sup-sea permafrost melts the methane bubbles to the surface adding to the green house gasses, which warms the atmosphere and threw several processes warms the ocean in turn which melts the sup-sea permafrost even further. Ice reflects more sunlight than open seawater. Ice has a higher albedo than water. As ice melts, more water is exposed absorbing more energy and heat the ice would have previously reflected, which causes more ice to melt, exposing more open water.
Already, changes have come to many coastal communities. Melting ice has already, and will continue to cause higher sea levels, forcing coastal communities to migrate inland away from the encroaching sea. Food webs that have evolved over a millennium of relatively stable sea ice conditions are changing drastically, due to the change in atmospheric conditions. With the major atmospheric changes comes a major change in weather patterns. These combined factors will cause a change in culture for the communities, such as the Inupiat who catch whales will more difficult to do so (http://www.nytimes.com/) (http://dsc.discovery.com/).
While at first glance the arctic sea ice may seem desolate, it is in reality a thriving ecosystem, rich with life. An ecosystem such as this, where much of the water consists of solid ice, is called a sympagic ecosystem. As sunlight filters through the ice, it allows for the growth and propagation of photosynthetic phytoplankton. Seasonal phytoplankton blooms occur on the underside of the ice and, in turn, cause an explosion in the population of zooplankton. These primary consumers then feed multitudes of secondary and tertiary consumers. Stated simply, thinning of sea ice means much greater average annual loss of ice to seasonal thaws, which potentially means the loss of primary producers, resulting in trophic catastrophes from the bottom up.
With a lifestyle linked closely to the sea ice itself, the polar bear (Ursus maritimus) was considered by a recent study to be one of the three arctic mammals most sensitive to sea ice change (Laidre, Stirling, Wiig, Heide-Jorgensen, and Ferguson 2008). Polar bears travel onto the ice pack in winter to hunt their primary prey, ringed seals (Pusa hispida). There they remain until the melting of their hunting platforms forces them to shore, where they often survive off of fat reserves while waiting for the ice to reform (Stirling 1988). The most critical time of the year for the bears occurs in late spring, when ringed seal pups are abundant (Stirling & Derocher 2007). If current warming trends continue, seasonal ice will form thinner than it has in previous decades. This means it will thaw sooner, forcing polar bears to choose between hunting seal pups on the ever-receding multi-year ice, or abandoning their attempts and moving ashore. The effects of such warming are being demonstrated now and can be quite dramatic.
Studies in Canada have shown that decreases in the body mass of pregnant female bears have occurred (Derocher & Stirling 1995). These decreases hold true for not only females, but the entire population. In addition, bears forced to fast for longer periods have shown increasingly desperate behavior. As bears spend more time ashore, due to increased distance between the edge of the ice pack and land, as has been reported in the southern Beaufort Sea population, interactions with humans are bound to increase, as hungry bears travel farther inland in search of food. Already, the number of bears killed in self-defense has risen from approximately three annually in the early 1990's to approximately ten annually from the years 1998 to 2004 (Sandell 2001). In the Beaufort Sea population, increased intra-specific predation (cannibalism) has been observed, probably reflecting increased stress and nutritional deprivation due to longer ice-free periods (Armstrup et al. 2006). Vagrant animals are beginning to show up further away from the sea, as evidenced in March 2008 when a polar bear was shot outside of Fort Yukon, roughly 250 miles south of known polar bear range (http://www.adn.com/).
Another species suffering from the thinning of sea ice is the Pacific walrus (Odobenus rosmarus). In September 2009, 131 walruses near Icy Cape, Alaska, were found dead, most likely crushed from a stampede of several thousand herd mates (http://www.nytimes.com/). Such large aggregations are considered highly unusual, and it has been speculated that this may be due to shrinkage or significant shifts in distribution of sea ice habitat. Pacific walrus, much like the polar bear, have a natural history that depends on sea ice. Ice provides walrus with free transportation with the current, a platform for birthing and nursing calves, and the ability to rest over offshore feeding areas (Laidre, Stirling, Wiig, Heide-Jorgensen, and Ferguson 2008). In the past, ice coverage in the northern Bering and Chukchi seas provided walruses with a platform from which they could easily access the benthic resources present on the shallow continental shelf (Fay 1982). Recent climate trends, which favor thinner seasonal ice, prone to premature melting, have caused the summer sea ice edge to recede many kilometers north of the continental shelf break (Cosimo 2002 & Walsh 2008). This means that in order to obtain food, walruses have had to expend far more energy by swimming and diving greater distances than they have in the past. This may not pose a problem for bull walruses—which habitually haul out on land during the summer to molt after breeding offshore during winter—but it does create potential obstacles for cows with calves (Reeves, Stewart, Clapham, and Powell 2002). Females, calves, and juveniles typically remain on sea ice year-round, with young bulls going ashore only after they've reached maturity. If ice retreated to such an extent that cows could no longer be in reasonable proximity to feeding grounds, they would have to either swim to shore or swim to a more favorable ice pack, possibly great distances away. Young calves would be quite disadvantaged and ill suited for such a swim, and since calves depend on maternal care for at least two years before becoming independent, mothers would either be forced to stay with their calves on marginal ice floes, risk taking their calves on extended swims, or abandon their calves (Cooper 2006). Moreover, changes in the population of walrus would radically alter the benthic ecosystem. Walruses are a keystone species, a species that has a disproportionate affect on its environment relative to its abundance, analogous to the keystone in an arch, the stone that feels the least amount of pressure, but will cause the entire structure to collapse if removed (Paine 1995). The feeding methods walrus employ to feed on various mollusks, crustaceans, and sea cucumbers, sifting along the sea bottom, disturbs the sea floor, releasing nutrients, and determining the layouts of various communities of benthic invertebrates (ADF&G) (Ray, McCormick-Ray, Berg, & Epstein 2006). Walruses are also important to subsistence communities, both because of the meat that is provided and the income obtained from handcrafted ivory (USFWS).
While one might initially assume that thinning of sea ice would positively affect bowhead whales (Balaena mysticetus), as with all other forms of arctic wildlife, bowheads live in a fragile environment and are very sensitive to change. The only true year-round Arctic mysticete, or baleen whale, bowheads have always been, and still are, vital components in the livelihood of the Inupiat. Every year, subsistence hunters harvest 25-40 whales annually, and indeed much of what we know about bowheads comes from the animals taken in this way (ADF&G). From the stomachs of harvested animals, it has been found that their principal prey include copepods (Calanus spp.) and euphausiids (Thysanoessa spp.) (ADF&G). These invertebrates feed on the phytoplankton that grows on the underside of the sea ice. Phytoplankton need brine associated with the cracks in thick multi-year ice in order to flourish. Trends towards warmer temperatures reinforce decline in multi-year ice, instead favoring thin, smooth, seasonal ice. This thinner ice may not provide enough brine for phytoplankton, which will limit zooplankton growth, and ultimately the ability of bowhead whales to feed. Shifts in plankton distribution may alter traditional bowhead migratory routes, making it far more difficult for subsistence-based societies to harvest the whales. Inupiat along the northern coast of Alaska depend upon bowheads for subsistence, the disappearance of the bowheads mean the disappearance of a unique way of life.
Another potential problem facing bowhead whales is the potential for range extensions of subarctic mysticetes due to earlier sea ice thaw. Seasonal ice has the propensity to thaw much easier than multi-year ice, and in a hypothesized scenario, this could mean earlier sea ice breakups as seasonal ice replaces multi-year ice and warming trends continue. Currently, five subarctic species of baleen whales enter the Arctic to feed each summer, humpback (Megaptera novaeangliae), fin (Balaenoptera physalus), minke (Balaenoptera acutorostrata), blue (Balaenoptera musculus), and gray (Eschrichtius robustus). Earlier arrivals at more northern locations by these species may cause potential exploitive competition with bowhead whales (Laidre, Stirling, Wiig, Heide-Jorgensen, and Ferguson 2008). One may argue that since bowheads are skim feeders, they would not be in direct competition with the incoming "substrate feeders" (gray whale) and "gulp feeders" (humpback, fin, minke, and blue); however, since bowheads feed at nearly all levels of the water column, the effects of even indirect competitors would most likely be felt to some extent (Day 2006). This proposed extension of range may already be occurring, with reports in 2007 indicating that an unsustainable influx of gray whales have begun to congregate around Barrow, Alaska in the summer (http://www.npr.org/).
One species not commonly associated with the arctic ice pack is the arctic fox (Alopex lagopus). In winter, when terrestrial prey may be hard to come by, arctic foxes sometimes follow polar bears out onto the ice to scavenge from seal carcasses provided by the bears (ADF&G). Arctic foxes may occasionally try to excavate ringed seal lairs to prey on pups (Eliot 2004). In a warmer future, arctic foxes would be unable to travel onto the sea ice if it formed far from shore. As a result, the foxes would potentially have to stay inland year-round. This would bring them into more contact with red foxes (Vulpes vulpes), which have been extending their range northward in recent decades. Studies have shown that through both exploitive (indirect) and interference (direct) competition, red foxes are ecologically dominant over arctic foxes where the species are sympatric (ADF&G and Rudzinski 1982). Populations of red foxes in northern Alaska are also subject to rabies outbreaks, which can decimate entire red fox populations, arctic fox populations, and possibly pose a threat to human settlements (ADF&G). Arctic fox populations fluctuate based on the multi-year population cycle of their principal summer prey, brown lemmings (Lemmus sibiricus) (Eliot 2004 and ADF&G). A year in which lemming populations experience a crash, coupled with competition with, and potential diseases introduced by, red foxes could potentially cause an arctic fox population to be unsustainable in the long run.
All four species of eider ducks breed in Alaska, and most remain in the coastal waters of the North Slope during the winter (ADF&G). These four species include the common eider (Somateria mollissima), the spectacled eider (S. fischeri), the king eider (S. spectabilis) and Steller's eider (Polysticta stelleri). In the winter, all species rely on polynyas—bodies of water surrounded by ice that remain ice-free all year due to currents or warm water upwelling—for feeding grounds, diving for mussels and other shellfish. Once the spring thaw begins, eiders migrate from the ocean to their nesting grounds, preferring either tundra or coastline habitats. If sea ice becomes thinner on average every year, the spring thaw will occur sooner, and this may cause eiders to begin to migrate before conditions at their nesting grounds are accommodating to the needs of nesting birds (i.e. still too much snow to build nests, ice still covering inland ponds so island nests may be accessed by predators, etc.). It has been shown that the time that eiders arrive is critical, with massive die-offs of many thousands of animals occurring due to unusual sea ice behavior (ADF&G). As mentioned before, eiders are diving birds that feed on mussels and other shellfish. These shellfish need specific habitat conditions to survive, conditions not necessarily met by newly eroded seabed. Thus, eiders would have to travel from their new nests to mussel beds and expend more energy to feed in locations that were once relatively closer.
The ringed seal (Pusa hispida), principal prey of the polar bear, relies on sea ice as both shelter, and habitat for favored prey. Before giving birth in late spring, females excavate subnivean (under snow) lairs in which they give birth and whelp their pups (Smith & Stirling 1975). Females prefer to carve these lairs along pressure ridges or in thick accumulated snow, both features of multi-year ice (Reeves, Stewart, Clapham, and Powell 2002). Studies suggest that decreased snow depth and changes in the timing of sea ice breakup correlate with reduced pup survival and reproduction (Ferguson 2005 and Stirling 2005). There is some evidence that inexperienced females will give birth on drifting pack ice, thus increasing the chances of pup predation by polar bears. More experienced mothers have been shown to prefer landfast ice (ice that has frozen or "fastened" along the coast), and thus have had higher reproductive success (ADF&G). Trends towards proportionally more seasonal ice means that multi-year ice, the kind that provides pressure ridges and thus good potential habitat for birthing lairs, will decline.
However, the threat to ringed seals does not stop there. As mentioned before, multi-year ice and its brine streams are necessary for the growth of phytoplankton and, in turn, the populations of zooplankton. Zooplankton are the prey base for polar cod (Boreogadus saida), which is the principal prey item for ringed seals in Alaska (ADF&G and Reeves, Stewart, Clapham, and Powell 2002). Polar cod is thus associated with sea ice year-round, and this is reflected in ringed seals' seasonal patterns. During the summer, they occur along the receding ice edge and selectively prey upon polar cod, even though it represents roughly 1 percent of the fish and crustacean biomass and is outnumbered by pelagic crustaceans (Reeves, Stewart, Clapham, and Powell 2002). If thinner seasonal ice begins to predominate, its effects on polar cod and ringed seals are not likely to be positive.
Barrow is located directly next to the Beaufort Sea. The ocean is rising at about 2mm/year; this steady rate will eventually cover the town of Barrow in seawater (http://www.agu.org/). As the sea is moving in, the township will be forced to relocate further and further away from the ocean. This will cost the government millions of dollars to move the city and ensure a proper clean up (http://www.nytimes.com/).
As the seawater encroaches on the land, fresh water will become increasingly scarce. The fresh water lakes that surround the Barrow area will become contaminated by seawater, and any fresh water fish, waterfowl, and/or surrounding plant life would lose their means to survive. Not only will the animals be affected by a lack of fresh water, but the people living in Barrow and the surrounding area will lose their access to fresh water aquifers. As the sea rises, it will slowly seep into the melting permafrost and leak into the fresh water aquifers, making any drinkable fresh water undrinkable (http://www.ngwa.org/).
Currently, there are only two ways of transportation into and out of Barrow, by barge and by plane (http://www.cityofbarrow.org/). Barges can only come in during the summer, leaving jets as the only year round access. As storms and bad weather increase, the ability of planes to enter Barrow will become increasingly difficult. As travel becomes difficult, there will be fewer tourists using planes and possibly less money from outside sources. The weather changes affect travel, but it will also change the activities available to the citizens of Barrow. More storms and higher temperatures will cause less favorable weather and any community outdoor activities will decrease substantially. With the recession of Arctic ice, the city of Barrow will become more accessible year round. Due to the open waterways, barges and other sea vessels will be able to reach once isolated Barrow and other northern towns. In September of 2009, two German ships traversed the Northeast Passage, and for the first time, a realistic shipping lane has been found in the far north (http://www.msnbc.msn.com/). With ships passing by in the north, this will allow the possibility of Barrow becoming a major port town and stop over for ships. This, in turn, will create economic growth, as well as expand the cultural diversity of the surrounding area.
Permafrost is ground frozen for two consecutive years or more (http://www.alyeska-pipe.com/Default.asp). Communities, such as Barrow, have built the foundations for building on permafrost for decades. With the weather warming, the permafrost is melting and the structures are becoming unstable. This melting is causing trouble when engineering buildings. Buildings are currently falling in on themselves. The permafrost under the buildings melts and turns into mud with a soup-like consistency. Roads, runways, and pipelines are left with no support on permafrost if it is not going to stay frozen.
Erosion is the natural process that slowly breaks apart soil and rock and move it from one place to another (http://geography.about.com/). The elements that cause erosion in the Arctic are wind, waves, ice, running water and rain. The Arctic shore is very susceptible to waves, running water, and ice. The coastal erosion in the Arctic has more than doubled over the last few years, at nearly 45 feet per year along 40 miles of coastline along the Beaufort. This erosion is a result of, "declining sea ice extent, increasing summertime sea-surface temperature, rising sea level, and increases in storm power and corresponding wave action" (http://geology.com/). This increasing erosion is also affecting coastal buildings; the foundations of the buildings are being undermined and the land they are built on is falling into the sea.
When the top layer of sea ice melts, during the melting season, while the bottom surface freezes with clean ocean water (http://www.springerlink.com/home/main.mpx). Sediment then freezes into the ice during the first freezing period. Ocean sediment is the fine granular pieces of soil and rock that have been eroded away and transported to the ocean via wind, or water (http://www.waterencyclopedia.com/). The sediment in the ice reduces the albedo thus increasing the affect of the sun on the ocean. Since there is now a higher ratio of first year ice to multi-year ice, there is now a higher percentage of ice that has sediment in it.
Recent changes in the Chukchi and Beaufort Sea ice regimes (reduced summer minimum ice extent, ice thinning, reduction in multi-year ice extent, altered drift paths and mid-winter landfast ice break-out events) have resulted in an increase of sediment-laden ice in the area. Apart from contributing substantially to along- and across-shelf particulate flow, an increase in the amount of dirty ice significantly impacts (sub-)ice algal production and may enhance the dispersal of pollutants (http://www.sciencedirect.com/).
Solutions to the problem
The problems facing Barrow—and indeed the entire North Slope region—while potentially disastrous, can be mitigated if quickly acted upon. By limiting dependency on fossil fuels, sequestering carbon emissions, and changing energy efficiency standards, anthropogenic factors influencing negative changes in sea ice thickness can be significantly diminished. By providing economic incentives, home energy efficiency can be improved dramatically, and by looking to algae as an energy resource, the "amount of raw resources used /amount of useable energy produced" ratio can be decreased while simultaneously sequestering current emissions.
Algae must be looked to as a new energy source for two reasons: firstly, it can be used to produce potentially massive yields of biodiesel; and secondly, it the process by which it yields the aforementioned biodiesel allows for the sequestration of emissions. After being cultivated in a photobioreactor, algae can be harvested and the naturally occurring oil (sometimes up to 60% of the algae's biomass) can be removed and be refined into biodiesel. When compared to other potential "oilseeds", algae proves to have the greatest yield. After comparing 18 gallons of oil per acre of corn to perhaps 5,000 gallons per acre of algae as estimated by the U.S. Department of Energy, one can see that algae is the most efficient option. After processing the algae's oil, remaining components can be turned into other products such as livestock feed.
In addition to sunlight, algae need carbon dioxide (CO2) and nitrogen dioxide (NO2) to grow. These compounds are common pollutants of power plants and automobile exhaust. If placed near production facilities that produce these gases through the burning of fossil fuels, algae production plants can use these compounds to "feed" algae, increasing productivity and cleaning up the air. By absorbing CO2 from these plants' flue gas, the algae may help address global climate change concerns (http://www.oilgae.com/).
Homes becoming more energy efficient will have many effects on the city of Barrow and all of the United States. Energy efficiency can be simply defined as a "percentage of total energy input to a machine or equipment that is consumed in useful work and not wasted as useless heat" (http://www.businessdictionary.com/). Energy efficiency standards as they are now will produce a carbon emissions savings of 980 million tons and a net economic $240 billion benefit. By becoming energy efficient households on average in the U.S. save 20% of their electric bill (http://ees.ead.lbl.gov/node/). The people not only help prevent thinning icecaps but their bills go down as well. Energy efficient products can be and are usually more expensive than non-efficient products making it hard to transition to, although in the long run they benefit the consumer by saving more money than it costs. With incentives that lower the price, such as producer rebates or government rebate incentive programs like the one already in Alaska, people will be more willing to make the change helping the environment (http://www.ahfc.state.ak.us/home/index.cfm).
The fossil fuels that we use today in our vehicles and heavy equipment produces CO2 that goes into the atmosphere where it acts as a green house gas; some CO2 is absorbed by trees, algae, and other plant life. Cutting down on gas emissions is an important step to reducing the current climatic trends that in turn will help to reduce the rate of sea ice decline (http://ecen.com/). To reduce fuel consumption societal wide adjustments need to be made in the fuel efficiency standards of automobiles, public transportation usage, and legislative support for local manufacturing and agriculture. All three substantially increase carbon emissions, fossil fuel consumption, and in turn sea ice decline.
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