Alison Higgins
11/11/16
Oceanography
Professor Zeeman
Climate Change and Antarctica
There is no denying scientifically that our world is facing some serious climate change issues, and it is easy to see this when we take Antarctica into consideration. Antarctica is the most symmetrical and southernmost continent on earth, located at the bottom of the globe. “Almost 99 percent of Antarctica is covered by an ancient ice formation measuring 14 million square km (5.4 million sq. miles) and averaging 1.9 km (1.2 mi) thick. The Antarctic ice sheet holds an estimated 61 percent of Earth’s freshwater resources(Global Issues)”. Antarctica plays a major role in the equilibrium of the world, when things shift at this location the effects can be seen worldwide. Sea level, weather patterns, temperature shifts and habitats for countless species are all affected by climate change in the Antarctic. Scientists are able to predict the future of the planet based off of data they have gathered at Antarctic research sites.
Antarctica is divided into three regions, the WAIS, EAIS and the Antarctic peninsula. The WAIS is the western section of Antarctica and makes up 20% of Antarctica’s land mass. It is a marine based ice sheet and has an altitude lower than the rest of the continent and because of that it is most heavily impacted by climate change. The EAIS is the eastern part of the continent and makes up 75% of its land mass. It’s higher altitude and position in-land means that it is less likely to be impacted. The Antarctic peninsula is the piece of land that juts out away from the primary land mass. It is surrounded by the southern ocean and makes up only 4% of the continents area. All of these sections experience climate change differently and they can all tell us different troubles the earth is facing.
The WAIS is at sea level at some areas and because of that it is in constant contact with the ocean’s water. That’s means that changes in the waters temperature can drastically affect the WAIS due to its composition of ice. The edges of the WAIS can recede very quickly if the temperature of the ocean water increases even by just a few degrees. Melting sea ice on a large scale can lead to a rise in sea level. “Where the bedrock under a marine ice sheet slopes down towards the interior of the continent, such as under parts of West Antarctica, the ice sheet may be unstable(Antarctica.gov)”. This instability under the ice sheets could cause them to erode and fall away, increasing sea ice loss. The WAIS contributes between .5-5m/century to sea level rise. A researcher by the name of John Mercer was one of the first to conclude that previous ice loss in the Western Antarctic was due to surface temperatures rising above freezing point and allowing the ice to melt. “The spectre of the imminent and rapid loss of ice from the West Antarctic Ice Sheet has been raised by dramatic events such as the collapse of the Larsen B ice shelf in 2002. (Nicholls).”
The collapse of the Larsen B ice sheet in 2002 resulted in an area of 1,250 square miles, an area about the size of Rhode Island, disintegrating and breaking off from the east coast of the Antarctic peninsula in little over a month. The collapse was witnessed by scientists who regularly monitored satellite images of the area. More recently we are seeing the collapse of the Wilkins ice shelf. “ The Wilkins ice shelf is in its final stages of collapse and scientists are concerned that the event shows climate change is happening faster than previously thought. (Garrett)”. The only thing connecting the Wilkins ice shelf to continental Antarctica is an ice bridge where at its narrowest is only 500 meters wide. The Wilkins ice shelf is one of eight ice shelves that have collapsed off of the coast of Antarctica in the last couple decades. Scientists are without a doubt contributing this to climate change and surface air warming.
The Antarctic peninsula is the most harshly impacted due to the fact that is it surrounded on three sides by ocean waters.This area is one of the fasting warming places on the planet. During summer months the warmer ocean temperatures cause the glacial area to melt and this does impact sea level negatively. Surface temperature in this area is increasing at a higher rate than any other area on the continent. Most of Antarctica’s marine animals reside in this region so loss of ice mass also means the loss of habitat for these organisms. Warming waters have begun eroding this ice shelf from underneath causing rapid ice loss. Sea ice loss is highest in this area. Although warming of ocean temperatures is normal during summer months and ice melt does occur naturally, global warming is causing these melting spells to extend farther in land toward the WAIS and the EAIS.
The WAIS and the Antarctic peninsula are linked due to their vulnerability when it comes to ocean temperature. The EAIS is at a higher altitude and does not make contact with the waters and because of this it is less likely to be influenced by increasing water temperatures. However,Warmer air temperatures allow the atmosphere to hold more water and therefore cause an increase in snowfall over the eastern region. The accumulation of snow many be causing the ice thickness to increase in this area. Some scientists hypothesis that this increased ice thickness i slightly counteracting the sea ice loss in West Antarctica and the Antarctic peninsula. Surface and air temperatures in the Eastern region of Antarctica are still well below freezing and therefore preventing ice mass loss. Westernly winds also play a role in the warming is this continent. During summer months these winds that circle the continent bring warmer air down from mountain slopes onto the eastern side of the peninsula, however these winds do not seem to have the same impact on the western side of the peninsula. Some scientists also hypothesize that an increase in greenhouse gases are trapping warm air near the surface of the continent causing the effects of global warming that we see such as loss of ice mass.
“During the twentieth century sea level rose by about 18 centimeters” however, due to the accelerated speed of global warming scientists are predicting a much higher number for the twenty first century. There is still a lot that is unknown about the effects of climate change on Antarctic and because of that the range in potential sea level rise is large. Some scientists suggest sea level rise will be between 18-59 centimeters while others predict as much as 80-200 centimeters increase in sea level. A project sponsored by the United Nations predicts that temperature will rise 3-4 degrees centigrade warmer by the end of the 21st century. This will undoubtedly cause massive sea level rises.
Sea level rise is a serious problem for hundreds of millions of people on earth. A major portion of our population live near the coast or depend on the coast for their livelihoods. Eight Percent of the world’s population, about 400 million people would be drastically impacted by a sea level rise of 6m or more. A sea level rise of 100-200 cm would mean a extensive loss of coastal areas. Just in the United States alone we would see a loss in coastlines and cities such as Miami, Boston and Portland Maine to name a few. Sea level rise has already caused loss of coastal areas and island nations. Economically speaking the increased loss of the Western Antarctic ice shelf could potentially mean abandoning large portions of the world’s coastline. “ up to 15 million people are expected to be displaced from 2030-2130.(Robel)”. This number could increase if cost of coastal protection continues to rise.
Four hundred million people, about 8% of the world’s population will be impacted by a possible 6m sea level rise that is expected to occur between the years 2030-2130. WAIS ice sheet loss will cause wetland loss, displacement of humans and marine animals, and increased cost of coastal protection to the point where coastal abandonment might be necessary in some areas. Sea level rise will cause issues in trade, and economic decline in many tourist dependant areas, as well as potential salt water inundation of freshwater sources and issues regarding water treatment plants, and destruction of established infrastructure. In Island nations and coastal areas where tourism is responsible for a majority of the nation’s economy, sea level rise could reduce coastal recreation such as watersports and scuba diving. It would also pose a threat to coastal resorts and tourism based businesses. This could cause a drastic decrease in annual income.
Sea level rise will also cause a loss of coastal habitats for marine animals. As the sea level rises the animals will be forced to move inland, however extensive development in most coastal areas will prevent this necessary migration from happening. That’s why it is essential for governments to create protected areas near the coast for these animals to be able to move to safely when and if there habitats are lost. “The polar regions, particularly the Arctic, are warming faster than the rest of the world, as a consequence, polar ecosystems respond directly to changes in the earth systems at the poles. (proquest)”. Many organisms migrate to the Antarctic peninsula to feed and because of this a loss of of a key food source could cause disastrous effects on a number of other species.
“Antarctica, where much of the ice overlays a continent, the warming alters streams, lakes and tiny plants and animals that live there. (proquest)”. An example of this is the krill population of the Antarctic peninsula. The krill population is supported by increases in phytoplankton blooms. Increases in phytoplankton are due to higher ocean temperatures which they thrive in. Krill are a keystone species in the antarctica peninsula due to their past abundance. They Serve as a keystone species with organisms such as penguins, seabirds, seals and whales dependant on it. Krill populations have declined by up to 80% since the 70s due in part to warming waters, acidification and sea ice loss. The loss of these numbers means that these species that depend on the krill have to find food elsewhere.
Another species drastically affected by climate change in Antarctica is the Adelie penguin. On the continent there are both ice dependant and ice tolerant penguins. The Adelie penguins are a “ice loving” species whose populations has significantly decreased due to ice loss. They are one of the four species of penguins in Antarctica, the other three are the Chinstrap, Emperor, and Gentoo penguins. The Adelie penguins live on the ice shelf of the peninsula and are dependent on sea ice for “ foraging, resting, molting and migrating”. It is necessary for the penguins to live on the peninsula due to its close proximity to the ocean. The edges of the ice shelf provide the Adelie with a habitat to raise young, rest and have access to their food sources in the surrounding waters. The ice also allows the penguins to migrate from one area of the ice sheet to another depending on availability of resources. Adelie numbers have dropped 65% in the last 25 years around the peninsula. The number of breeding pairs has decreased by 83% since 1974 and one of what was five colonies has since gone extinct. Ice tolerant species are now making up a majority of the penguin populations in the continent.
Seals and whales are also being affected by climate change in Antarctica. Some species, similarly to the Adelie species are dependent on ice for survival. Loss of sea ice means less reproduction and foraging. Many species are also dependant on krill or even in some cases penguins or other fish populations as a food source. Not only do these species have to deal with warming waters and loss of habitat but they also face loss of food sources due to the impact of climate change on other populations of marine organisms in the area. Scientists fear that populations of certain ice dependent species will face declines in population numbers similar to that of the penguins. Polar bears are facing similar problems in that they are losing their primary habitat with the loss of sea ice. Polar bears depend on the ice shelf for reproductive purposes as well as living space and food sources. With the loss of sea ice comes the loss of food, habitat and comes with a decrease in reproduction rates in these marine species.
In addition to the loss of sea ice and in turn loss of habitat, the melting of permafrost, which is ice that stays consistently frozen year round that overlays soil is causing the “creation of a boggy, uneven landscape with a disrupted surface. Subsequent rain or snowmelt can erode this surface, carrying silt and sediment into bodies of water, changing the paths of rivers and streams (proquest)”. This increased sedimentation is another disturbance that marine and other arctic organisms such as insects, algae and a variety of fish have to deal with. Despite popular belief there is vast amounts of life on the continent of Antarctica. Lakes, streams and rivers contain populations of microbes including plankton and algal mats. Increased melting of Antarctic permafrost will increase freshwater and therefore may also increase populations of freshwater species on the continent.
Increased levels of CO2 is being absorbed into ocean waters due to increases of greenhouse gases in the atmosphere. The increased levels of carbon dioxide in the water results in ocean acidification. Ocean acidification alters the pH levels in the water and this will put an increased amount of stress on marine organisms in the area. Of course is is a more broad result of climate change because it is affecting waters all around the world but it is an example of yet another stressor that marine organisms in the arctic are facing. These stressors could cause a decrease in reproduction rates, and even potential migration in search of less acidic waters. Ocean acidification in the Antarctic waters will negatively impact fish populations and therefore cause the Antarctic marine fishery to suffer.
It is obvious that the continent of Antarctica is experiencing some serious changes due to climate change. Serious sea ice mass is one of the major contributors to sea level rise globally and scientists predict that seas will rise between 10-90 centimeters within the very near future. This extreme sea level rise will lead to the loss of significant amounts of coastal areas worldwide. Loss of coastal cities such as Boston and Miami as well as the loss of island communities including the Maldives will directly affect human populations and lead to the need of relocation. As we see the changes that we will soon have to face many scientists are beginning to have to make plans for mass relocation of both humans and coastal organisms. It is essential for the governments of countries around the world to take quick action in reducing greenhouse gas emissions if there is any hope in saving the Antarctic ice sheets. The loss of these sheets will not only affect the local ecosystems but have negative impacts globally. As i stated earlier, the loss of the entire Antarctic ice sheet would result in an increase of sea level by around 60 meters. Of course the loss of the entire ice sheet is still hundreds of years away but every time an ice sheets erodes we are facing sea level rise.
Although Antarctica is not inhabited by humans it can still strongly impact every human on the planet. Loss of keystone species affects populations of numerous species, including species that are a major part of the Antarctic fishery. Often times people don’t feel connected to an issue unless it is directly affecting them. The melting of the Antarctic ice sheet is something that will drastically impact every person on the plant if it is not acted upon as soon as possible. Economies, food sources and entire nations will be negatively impacted by the rise of sea level which is a result of the melting of the ice sheets. This is an issue that everyone should feel personally affected by because it is going to change the world in future years. More information and coverage of this issue is necessary to educate people on what i really happening and what serious consequences their actions have. Hopefully in the near future this issue comes to light in the media and people will actually start to take steps towards improving the conditions on and around our southernmost continent.
references:
Works Cited
- Robel, Alexander. “The long future of Antarctic melting.” Nature 526.7573 (2015): 327+. Global Reference on the Environment,ENERGY, and Natural Resources. Web. 9 Dec. 2016.(source found through une library services)
- “Antarctica: Climate Change.” Global Issues in Context Online Collection, Gale, Cengage Learning, 2016. Global Issues in Context, une.idm.oclc.org/login?url=http://link.galegroup.com/apps/doc/CP3208520474/GIC?u=bidd97564&xid=98786a21. Accessed 9 Dec. 2016.
- Lindsey, Rebecca. “Collapse of Larsen B ice-shelf” Earth Observatory. NASA.gov (January 2002)
- Ice Sheet and Sea level Rise, Australian Government department of Environment and Energy. ( Feb 2014)http://www.antarctica.gov.au/about-antarctica/environment/climate-change/ice-sheets-and-sea-level-rise
- Monaghan, A (2009, Jan). Antarctica and Climate Change. World Watch, 22, 6-12. Proquest.(source found through une library services)
- Nicholls, R.J, Tol, R.s., J. & Vafeidis, A.T. (2008) Global estimates of the impact of a collapse of the west antarctic ice sheet: An application of FUND. Climactic Change, 91 (1-2), 171-191. Proquest (source found through une library services)
- Climate change; polar climate change may lead to ecological changes. (2011). Ecology, Environment & Conservation (source found through une library services)
- Warming to blame for ice shelf collapse: Garrett. (2009, Apr 07). ABC Premium News (source found through une library services)
