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Marine Ecology Paper
GLOBAL WARMING AND THE MELTING ARCTIC POLAR ICE CAPS:
The Endangered Lives of Polar Bears
The Twenty First Century has to this day been marked by constant war and strife. Religious wars, and terrorism is on the minds of much of the world’s population, but a potential global threat seems to be on the back burner. The rising threat at hand is global warming. It has no prejudice, and will strike indiscriminately around the globe with possibilities of displacing millions of peoples. A significant rise in sea level as a result of ice sheets in Greenland and Antarctica melting may totally destroy lowland countries like the Netherlands, coastal India and China. It may even have a dramatic affect here in the United States in such places as Manhattan and much of Florida. Aside from these very real possibilities there is already a significant biological and moral problem facing us today. Animal populations in these arctic regions are being severely threatened, species such as emperor and Adelie penguin as well as the polar bear. The melting ice is destroying these animals way of life and is something that humans should take notice of because it may foreshadow a significant change in our own habitat and way of life. This paper will explore the basic principles of global warming and its affects on the polar ice caps, but will focus on greater detail how this may destroy the lives of one particular animal species, the polar bear. Lastly, it will conclude with possible solutions and prevention plans in order to sustain the polar bears way of life and how to combat global warming.
To understand global warming, one must first be aware of how the transfer of heat works on our planet in what is commonly referred to as the heat budget. In order to maintain a steady temperature on earth, (on average it is around 16 degrees Celsius), the incoming radiation and outgoing radiation, which are responsible for warming and cooling the earth, must be on par. That is to say that if anything were to trip up this delicate process, such as perhaps adding more carbon dioxide in the air, a greenhouse gas, there may be dramatic consequences. In other words, the earth’s atmosphere and its gases are very fragile, and they play significant roles in heating and cooling the earth. The atmosphere is responsible for reflecting, absorbing and re-radiating the incoming solar radiation from space. The sun’s rays that pass through the atmosphere are then absorbed on the earth’s surface, which then are either re-radiated back into space or conducted and evaporated back into the atmosphere. This process helps to keep our planet warm, and also to maintain and sustain heat on our planet. More importantly in relating to the topic at hand, the importance of ice and ocean water on our planet must not be understated. The polar ice on our planet works as a giant mirror in reflecting the incoming solar radiation. It does a great job of this, nearly ninety percent of the suns rays at the poles are reflected back into space. However this all important job that the polar ice caps fulfill is being threatened by global warming.
In getting back to the initial problem of pumping more carbon dioxide in the air, we can now more fully understand how this will upset the very delicate process of heat transfer and the heat budget. Carbon dioxide is one of several gases in our atmosphere that are transparent to incoming short-wave radiation, but absorb outgoing, long-wave radiation from Earth’s surface. An increase in the atmosphere’s carbon dioxide level also increases the absorption of incoming infrared radiation by the atmosphere and decreases the infrared reaching Earth’s surface. The result of increased absorption of infrared energy in the atmosphere due to increasing carbon dioxide is the warming of the atmosphere. The retention of the outgoing radiation from the earth’s surface is what keeps the earth warm, which is what is commonly called the greenhouse effect. However, an increase in carbon dioxide as mentioned before will only cause more of the sun’s rays to be trapped in our atmosphere, not allowing them to be re-radiated back into space. The burning of fossil fuels, destruction of forests and increasing populations all play a part in increasing carbon dioxide and are all under human control. Consequently this warms the earth’s surface and ocean temperatures, most prominently at our poles.
Now this giant mirror known as the polar ice caps is becoming more and more diminished because of increasing water temperatures, and it is no longer working as efficiently. What is feared, and possibly what is already happening is that the “mirror” is no longer reflecting ninety of the sun’s rays anymore, further warming the earth. It is a snowball effect, an exponential decrease occurs in polar ice as more and more ice is being depleted. The less ice there is the more absorption will occur. The more absorption occurring, the greater the shrinking of the polar ice by an increase in polar water temperatures causing a very real possibility that within a century there will be no more polar ice left. This of course will yield unprecedented catastrophes on an incredible scale. Larger storms may form due to an increase in water temperature and wind, flooding of lowlands displacing millions may also result, and an overall increase in freshwater (due to the melting arctic ice caps and Greenland) into the very salty waters in the north Atlantic may cause a shutdown of the gulf-stream causing another ice-age.
The melting of the polar ice is something that is already occurring at an alarming rate. The first victims of global warming will be/are the higher latitudes of land ice, which surround much of the polar ice caps. The melting of land ice, and thus the displacement of freshwater into the ocean further warms, and depletes the greater ice caps in the polar regions. What scientists did not predict were how fast this processes would occur, and perhaps was a miscalculation of their own. The two greatest ice sheets on our planet of course are located at the two poles and are Antarctica and Greenland. Scientists have always observed the seasonal melting and re-freezing of ice in these regions, but measures in the past few years have shown incredible loss of polar ice in Antarctica. Enormous ice sheets, and sea-ice is being depleted and breaking off into the surrounding oceans. Even more alarming is the presence of enormous moulins in the area sprouting off from glacial pools and lakes. A moulin is a tunnel of water that leads directly down to the bedrock from the surface of the ice-sheet and is something that is regularly occurring in these polar regions. Scientists however are now noting that these moulins are not only increasing in size, but also in regularity and in greater numbers. To make matters worse these moulins are not acting as they did in the past, and in some cases as the water tunnels down into the bedrock it is actually causing large sheets of ice to separate and slide. The refreezing of water is not occurring, and a study conducted in Antarctica in the past year has yielded unprecedented results.
An entire ice shelf in the Larsen ice sheet in western Antarctica in a matter of months has completely disappeared. There were first recorded moulins and glacial lakes in the area, but within a few months scientists could view just how rapidly the ice was being displaced into the ocean. Even more alarming was when the sea-ice was depleted up onto the land-ice; the land-ice then also began to slip into the ocean like someone took the cork off the barrel. This exponential decrease in ice in the polar regions is what is worrying so many scientists around the globe. Not only did the land ice not re-freeze like what was to be expected, it actually tunneled all the way down to the bedrock causing further slipping off ice-sheets. There are now observations of huge cracks in the ice occurring all along Antarctica, which decreases the greater ice-mass and decreases its efficiency as a whole to work in reflecting the sun’s rays. Once again, this may cause even more severe problems such as a rise in sea level globally.
In Greenland, the second largest ice sheet in the world, the same observations are being recorded. Even more important, and more applicable to this essay is the affect this has on the polar regions and its animal populations. Polar bears only live in the northern arctic regions, and thus the melting that is occurring in the northern arctic is much more relevant. In the arctic tundra in Alaska and Greenland enormous ice chunks are drifting and breaking apart from the larger ice sheets. In Alaska on a daily basis, tourists can see enormous glacial ice chunks falling off into the oceans. In Greenland, moulins are centralized in the larger ice sheets and are occurring with such intensity that scientists can witness firsthand raging rivers and “waterfalls” tunneling directly down into the bedrock. In 1957 the United States government started a study to record how quickly the melting in the North Pole was occurring. The study shows that since 1976, sea-ice extent has dropped by 1.5 million km^2. That is an enormous amount of melting and is something that no longer can be afforded to ignore. Some scientists from this study conclude that within fifty to sixty years that no polar ice will exist in the North Pole. The largest ice mass in the Northern polar region, the Ward-Hunt ice shelf literally broke apart four years ago. It looks as if an earthquake centralized in the ice, and caused a gap of more than three meters to exist in the ice shelf. Alaska, which over thirty years ago had its underlying layer of permafrost frozen 225 days of the year, only has around a total of 75 frozen days a year now. That speaks to the larger issue of rising global temperatures, but one can gather from that information that ice is breaking apart, and melting away.
The North Pole seems to have been severely hit hard by polar melting in the past few years, which is of great concern to the polar bear. The extent of Arctic Sea ice has experienced a steady declining trend during the past thirty three years, based on a new comprehensive analysis of satellite data collected by the United States Coast Guard and Navy as well from the NOAA. “The new data sets show shrinkage in the Arctic Ocean summer ice cover of more than eight percent per decade…” according to Pablo Clemente-Colon, the chief scientist in the study. The data also confirms that the overall trend in summer, winter and multi-year total ice extent is down. Another study conducted suggests that September ice has also been decreasing. On September fourteenth of this year the melting season in the arctic came to a close, which is known as the sea-ice minimum, with sea-ice covering 5.7 million square kilometers, the fourth lowest of the twenty-nine year study conducted by the National Snow and Ice Data Center, (NSIDC). The average sea ice extent for the entire month of September was 5.9 square kilometers, the second lowest only to last year’s results. The study also suggests the summer breakup of Arctic sea ice “has crept an average of .75 days earlier a year, or 7 to 8 days a decade.” The dwindling September sea ice not only speaks to the extent of global warming, but also on a more personal level on how it is affecting how the polar bears feed, and survive. Julienne Stroeve, a research scientist for the NSIDC said, “At this rate, the Arctic Ocean will have no ice in September by the year 2060.”
The loss of summer sea ice does not bode well for species like the polar bear, which depend on the ice for their livelihood. What this means is that the polar bear will have less and less time on the ice in the years to come, which moreover suggests that they will have less time to feed and stock up on food to prepare themselves for the summer months when they migrate inland. The more time spent on land is another issue, dangerous for many reasons such as increased hunting quotas being issued in Alaska and increased contact with humans. The way polar bears hunt is extremely unique and fascinating. Aside from being one of the more glamorous and popularized animals in our society today, little was known about the polar bears eating habits until recent studies. They in fact do not live on Coca Cola, but rather have a unique style of hunting that requires the presence of ice. They rely on their keen sense of smell, and incredible hearing to hunt and kill seals that live under the ice. In a technique that is fascinating to observe they use their nose to sniff around the ice, but also pick up vibrations in the ice with their ears that may alert them to presence of ringed seals that poke their noses through the ice for air and sometimes the occasional beluga whale. When they pick up these vibrations they immediately summon up their stalker mode as to not alert the prey of their presence. Then by using their enormous front paws and sufficiently sharp claws they rear up on their hind legs and propel themselves downward like a giant dagger cutting through the ice, hopefully piercing their potential prey.
This type of hunting depends entirely on the presence of ice. Polar bears do not have the ability to outrun prey that dwell on the land, nor do they have the capability to find food elsewhere in their arctic environment because such few resources exist. They also are excellent swimmers, but of course rarely jump into the water to catch their prey because they would immediately alert the seals or whales of their presence. Thus, the only way a polar bear can successfully hunt is with the presence of ice to aid them. In fact, they use their excellent swimming ability to transport themselves from ice patch to ice patch, but with the dwindling ice in the area this has become a larger problem. For the first time ever recorded, there have been polar bears being found who apparently drowned by failing to reach a strong enough patch of ice to hold them. This is an unfortunate occurrence, and is undoubtedly a result of the dwindling ice in the polar regions because of global warming.
Scientists have become increasingly more nervous about how quickly the melting arctic ice has affected polar bear populations. Biologist Camille Parmesan of the University of Texas notes, “What surprises me most is that it has happened so soon”, who along with many other scientists did not expect extinctions to occur until the year 2020. However, her study suggests that animals like penguins and polar bears that are dependent on sea ice are facing significant threats from global warming, and their habitats are being destroyed. Parmesan also notes that, “Artic polar bears living in Canada’s Hudson Bay, at the southern end of the species range are fewer in number, and scrawnier because they lack the ice they require to feed from.” As a result of the reducing thickness, and presence of ice in the area some places are just too thin to support a polar bear. This eliminating factor in polar bear populations, scientists note is something that humans should realize. Climate change may in the future affect habitats that humans depend on to live, and animal extinction may only spell out ways in which the human species may eventually be threatened. The mating season, and sometimes even the birth of a baby polar bear may occur on the ice as well, which only further jeopardizes the livelihood of the polar bear. However, perhaps the greatest amount of anxiety raised about this issue is the amounts of time polar bears now have on the ice to feed and hunt. Most bears spend their summer months on land and fast until the ice forms in the fall, when they can use the ice as vast platform from which to hunt seals and belugas. More studies in the Hudson Bay area suggest that this wait on land, and bears’ period of fasting, has increased by three weeks since the 1970’s. The population there is noticeably skinnier there as well, and the population as a whole has decreased by fifteen percent. More occurrences of drowned bears have been spotted here as well. Four bears have turned up dead, unable to successfully swim the record long 160 mile trek.
Another result of the melting polar habitats where polar bears make their homes, is the fact that now they are spending more time on land. Consequently, they are coming in contact more often nowadays with humans, and hunters. This can only further deplete their populations as some Inuit villages that neighbor the polar bears habitats have increased hunting quota’s. This leads to unfamiliar encounters for both the bears and humans, who are not accustomed to each other, provoking violent attacks from both parties. Without sufficient strategies provided for people to be safe around bears, and invading their territories, the likelihood the bears will be hunted and killed even out of protection increases. Regional governments without sufficient data implementing the melting polar regions in reducing the bears' habitats have little to go on, and therefore automatically assume that the bear population is growing contrary to what we know now. In the northern Canadian province of Nunavut wildlife officials upped hunting quotas, increasing the total allowable bear harvest by almost twenty-nine percent.
The correct study, however, shows the truth to be that in fact the bear population is decreasing, and more bears are moving inland to find relief from the fleeting ice caps. The move inland coupled with the bears being hungrier because of the inability to hunt with the lack of ice has undoubtedly increased tensions between humans and bears. The hungrier and famished female bears are also experiencing, as a result, lower birthrates because of their lack of sustainable and healthy weight. “The average weight of adult female polar bears in western Hudson Bay has dropped by nearly 150 pounds in just 25 years…” a study conducted by the Canadian Wildlife Service suggested. All of this can be directly tied back to global warming, and the melting of the polar regions. The bears move inland, lack of good hunting grounds, famished mothers unable to produce, and increases in hunting are all results of global warming and it is undeniably endangering the existence of the polar bear.
A quick solution may not be in sight, and this is obviously a very serious and real threat that faces the polar bears today. However, we must as a global race recognize that we do have the power to control the amount of carbon dioxide in the air, and thus the ability to prevent and combat global warming. The lives of the polar bears are undoubtedly endangered in the world today, but also this may only be foreshadowing of what is to come, and happen to our own species. In order to save the polar bear we must do the same things that will prevent possible sea level rises, increased intensity of storms, and sea level rising because they all relate and come back to central problem of global warming. The use of renewable resources, recycling, decreasing fossil fuel burning and forestation and crop burning, or just by being more efficient with controlling pollution are all valid ways in which we can stop global warming. This is not a natural occurrence, and the rate at which are planet is warming and increasing in carbon dioxide is unprecedented. In order to save the polar bears, and perhaps our own race is to take heed of these warnings, and begin to understand the complexities behind global warning and the melting of the polar ice caps. If we intend to continue to represent the polar bear as a happy and lovable creature, then the best thing is not give him a Coke, but to help in keeping his natural habitat around and in order, because in the end it can only benefit us.
1) “Polar Bears Being Considered for U.S. Endangered List”, John Roach. The National Geographic News. February 10, 2006.
2) “Warming to Cause Catastrophic Rise in Sea Level?”, Stefan Lovgren. The National Geographic News. April 26, 2004.
3) Polar Bears Suffering as Arctic Summers Come Earlier, Study Finds”, Sean Markey. The National Geographic News. September 21, 2006.
4) “Global Warming Already Causing Extinctions, Scientists Say”, Hannah Hoag. The National Geographic News. November 28, 2006.
5) Film/Documentary for supplied background: “An Inconvenient Truth” directed by Davis Guggenheim.
Two Studies released by NSDIC News:
“New Data show downward trend in Arctic Sea ice” – taken from www.nsdic.org
November 20, 2006.
“Arctic Sea ice shrinks as temperature rises” – taken from www.nsdic.org
October 3, 2006
*These were press releases from the National Snow and Ice Data Center (NSDIC), which is part of the Cooperative Institute for Research in Environmental Sciences at the University of Colorado at Boulder.
1) “A Note on Summer CO^2 Flux, Soil Organic Matter, and Microbial Biomass from Different High Arctic Ecosystem Types in Northwestern Greenland”, M.H. Jones; J.T. Fahnsteck; P.D. Stahl; J.M. Welker. Arctic, Antarctic, and Alpine Research, Vol. 32, No. 1. (Feb 2000), pp. 104-106. University of Colorado.
2) “An Estimate of the Flux of Iceberg Calving from Greenland”, Grant R. Bigg. Arctic, Antarctic, and Alpine Research, Vol. 31, No. 2. (May 1999), pp. 174-178. University of Colorado.
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