Global Environmental Change Effect on Polar Bears - Research Paper Example

Global environmental change – effect on Polar bears Technical Summary Global warming, owing to anthropocentric activities is the most alarming problem to the world. High level of carbon dioxide in the earth’s atmosphere is creating the green house gas effect and eventually heating it up. The colder regions such as arctic and Antarctic are under immense risk, since many species there are now exposed to the risk of extinction. Furthermore, presence of high level of black carbon in the atmosphere of the Arctic region coming from the far south via winds is another factor responsible for the increased temperature of the arctic. (Tollefson, 2009, p. 29) The arctic holds an important place in the debatable issue of maintaining life on earth in a sustainable way. However, this discussion centres on the Arctic region itself and more precisely on depleting population of the arctic Polar Bears rather than the chain effect of the susceptible artic on the rest of the world. The last hundred years have witnessed an increase in global temperature by 0.6 degree centigrade. (Jenssen, 2006, p. 78) Moreover from 1976 the rate is even higher and unmatchable by any time encompassing past thousand years. The effect of such rise in temperature is most visible through the extent of ice melting in the high and mid altitude area. In less than fifty years the snow has decreased by 10%. (Jenssen, 2006, p. 78) For the survival of a species, the survival of its habitat and food source is of utmost importance. With the rise in global temperature the extent of ice will decline in the Arctic and so will its duration of frozen state, resulting in less area for the seals to stay and breed. Seals are the most important food source of the polar bear; so any effect on their population will directly reduce the food basket of the polar bears. It has also been observed that for large mammals any change in global temperature affects the juvenile survival rate. From this point of view both the seal and the bear are equally exposed to risk. Therefore the bear suffers from two sides - reduced present and future food source and reduced juvenile survival rate. Again the polar bear hunts on ground (solid ice). Any reduction of ice extent will leave the bear with smaller ground to catch seals. (Jenssen, 2006, p. 78) In front of global climatic change the arctic ice plate has also undergone changes in terms of thickness and has become fractured in many places. Furthermore the ocean now freezes in later part of the year and all these in a cumulative way are depleting the habitat of polar bear. (O’Neill et al, 2008, p. 1650). Another possible threat is hunting and experts believe that if not a total abduction from hunting is possible, a much careful approach to hunting should be followed without any delay. (O’ Neill et al, 2008, p. 1657) Climate change and hunting are not the only point of concern. Endocrine disrupting chemicals and mercury poisoning are the other two contaminating agent constantly eroding the arctic and thereby its largest on ground predator the polar bear. Anthropogenic Persistent Organic Pollutant (POP) has been found in polar bears. POPs are resistant to physical chemical and biochemical degradation and have a much longer life and hence they are absorbed through food or bioaccumulation. Though polar bears have a mechanism that metabolise and excrete POPs, yet owing to the fact that it feeds on large amount of seal blubber, level of POP in polar bear is higher. Since higher level of POPs affects both progesterone and testosterone levels; so it will definitely have a negative impact on the reproduction of polar bear. The relation between thyroid hormone system (TH) and POP is another point of concern. POP often has negative impact on endocrine-disrupting compounds (EDCs) and that might eventually lead to disruption of the TH resulting in lesser development of the neuro system. Polar bear’s development of cognitive abilities and successful learning of the hunting process leads to successful survival. Therefore a less developed neuro system might leave the species with less power of adaptability with changing topography of arctic, courting global climatic change. (Jenssen, 2006, pp. 77-78) Moreover around 200-300 tons of mercury gets transported annually to the Arctic through atmosphere and ocean currents that have made the western arctic particularly vulnerable to mercury poisoning and has exposed the polar bears to toxic effects resulting from the same. (Sonne et al, 2007, pp. 1; 7) Introduction The politicians and the policymakers alike along with the scientists are nowadays concerned with three P s pollution, population and poverty. Though different in meaning and apparently standing for separate problems somewhere they are interlinked and connected with each other with a spiral of events eventually strengthening each other. The present paper though primarily deals with the factors leading to a declining population of polar bears and the reason behind those factors, yet at the end an inter connection among these three burning Ps will be drawn to portray the condition in the Arctic at the foreground of a global scenario. The Arctic was almost untouchable before the 17th century regarding human activities. A handful of aboriginal people sustained their living at the Arctic and that left its ecosystem secure. From 17th century onwards the scenario changed, owing to the various scientific and mercantile expeditions to find Northeastern and Northwestern passages. For the first time in history, potential of the Arctic region as a source of natural resource, came to the notice of the human civilization and they got indulged into its unprecedented exploitation there on. Within a span of 100 years species like Steller’s sea cow was hunted to extinction and number of Walrus and that of Bow Headed Whale depleted to an alarming level. (Jenssen, 2006, pp. 76-78) However it is collectively believed by the scientists that habitat loss is the most problematic situation for specie to sustain its existence and that is just what happened for the polar bears over the last centuries. Most strikingly the present scenario of the Arctic is mostly the result of actions elsewhere far from this land of eternal ice. The industrial revolution in England brought a distinctive change in human life. Before the industrial revolution men were primarily occupied with agriculture and used to live in rural land. Though agriculture too had its toll on environment by reducing forest area, yet that was far too better than what industrialization was about to cause over the years to come. Industrialization led to urbanization and for both factories and settlement need of large piece of land was soon felt. Miles after mile forestland got swallowed into the womb of development and growth and soon the world found it self among skyscrapers. The world got divided into two parts developed and underdeveloped. Before the industrial revolution woods were mostly used to build furniture, houses or considered as a raw material for household fire. After the industrial revolution logging became a lucrative business catering urbanization and factory building. Furthermore it was often used in furnace to steam up the boiler. The world became far less green than it was and its consequences were yet to be felt. The plant specie uses carbon monoxide in photosynthesis that is exhaled by most of the other members of the living genome. As the number of plants declined and the number of human beings increased; the percentage of carbon monoxide in air raised as well. This was further aggravated with industrialization as sky touching chimneys relentlessly emitted black smoke full of carbon monoxide and other harmful gasses into air. This carbon dioxide together with methane, water vapour, nitrous oxide and ozone creates greenhouse gas. Earth reflects away around 28% to 30% of the total radiation that it receives from the sun. This helps it to keep cooler. The greenhouse gas absorbs this radiated heat and keeps it confined within the earth’s atmosphere and there by increases its temperature. Furthermore the part and parcel of urban life; the refrigerator and the air conditioner emits harmful chlorofluorocarbon another harmful gas compound that along with contributing to greenhouse gas effect depletes the ozone lair of the earth’s atmosphere as well. Therefore there is a direct correlation between the industrialization, urbanization, greenhouse gas and global warming. Another cumulative nature of this process would be worth mentioning; hot air can contain more water vapour than the cold one, so the greenhouse gas effect is self-cumulative. Once it manages to increase the temperature of the air, the air starts to absorb more water vapour and thereby strengthens the greenhouse gas effect. Again plants vaporise the excess water into air through the leaf holes and that keeps the air most and cool. Less number of plants leads to less rainfall and that in another way warms up the earth’s atmosphere. In this context, Hoag (2010) observes, “Although the Arctic Ocean accounts for only 3% of the worlds ocean surface area and is mostly covered in ice, it takes up 5-14% of all the CO2 absorbed by the planets oceans. It tends to take in proportionately more CO2 because gases dissolve more easily in cold water.” (Hoag, July 22, 2010) The Arctic is a sea of ice that when frozen extends thousand of miles; truly an icy continent. Rise in global temperature has hindered the freezing of ice both in terms of time and volume. It has curbed its extent and has resulted in delayed freezing as well as shorter solidified state. Towns et al. (2010) have highlighted this in a recent study “In particular, sea-ice break up is about three weeks earlier than 30 years ago…” (Towns et al. 2010, p. 209) The ice plates also are of lesser thickness and that might fail to keep a heavy bear afloat. Repeated fragmentation of ice is also a problem for the bear. Such an example of thinning of ice and repeated fragmentation as well as decline in ice cover in various parts of Atlantic can be found from a recent study of Stirling and Parkinson (2006): “Over the last 20 years or so, there has been considerable documentation of significant reductions in sea-ice cover in several parts of the Arctic, thinning of multiyear ice in the polar basin and seasonal ice in Hudson Bay, and changes in the dates of break up and freeze-up of the sea ice, likely as a consequence of climate warming”. (Stirling and Parkinson, 2006, p. 262) Polar bear is a land living mammal that requires space for travelling and hunting. Reduction of that place will definitely pose threat to its habitat. First of all seals are the most important food source for polar bears and reduced place implies now seals have less area to reproduce. Less number of seals will reduce the number of preys available to hunt. Again with less area to run and hunt seals, the rate of success in catching pray will get reduced for a bear. This twin attack on habitat would definitely leave many of them fasting (the fasting period which is the difference between the sea ice break up and freeze up date will rise and the hunting period will be shorter than before) and some of them may also succumb to that situation as referred by Towns et al. (2010) “climate change, through warming temperatures, has adversely affected the population, its habitat, and its prey.” (Towns et al. 2010, p. 210) The negative impact of global warming on the Arctic polar bears through a rise in the number of ice free days and open water season is well illustrated by Gleason and Rode (2009) through a number of secondary resources published at different times. This might be quoted a follows: “The minimum areal extent of sea ice has been documented since 1998, and new record lows were reached in every year from 2002 to 2005 (Maslanik et al., 1999; Stroeve et al., 2005), and again in 2007 and 2008 (NSIDC, 2008). Rode et al. (2007) documented declines in bear size, body mass, and cub survival and determined that at least some of those changes were associated with the increase in duration of the open-water season. Regehr et al. (2007a) documented declines in survival of adult females and cubs of the year during recent years with longer ice-free periods (2000 – 05). Further, Regehr et al. (2007b) documented an increase in the number of days within a year that are considered “ice-free” (defined as < 50% ice cover); the overall annual mean number of ice-free days increased by 16.7 days from 1979 to 2006”. (Gleason and Rode, 2009, p. 410) Hutchings and Bianchet (2009) have given a few estimates (collected from secondary sources) of polar bear habitat loss in coming time. As noted by them, optimal bear habitat loss will be 13% in 2050 comparing to the present state. Estimated fall of the entire polar bear territory within the four eco regions in 45 years (2006-2051) will be between 3% and 33%. The same pooling all the eco regions together will be 155 to 24%. Furthermore the winter extent of ice and that of summer extent will decline by 15% to 20% and 30% to 50% respectively. Again the sea ice in September will decline by around 30%. It has been further estimated that in next thirty-six years quality of polar bear habitat will decline by more than 30%. (Hutchings and Bianchet, 2009, p. 50) It can be easily figured out that such a decline directly or indirectly owes its route to global warming. The above discussion goes well with Jenssen (2006). According to Jenssen over the past 100 years Earth’s atmosphere has been warmed up by 0.6 degree centigrade. Consequence of such warming can be seen in decline in snow cover and ice extent by 10% in mid and high latitude area since the end of 1960s. Like the others discussed in this paper by now; Jenssen also holds the view that rise in global temperature will reduce the ice in the Arctic and that will lead to a disaster for the Arctic seals considering their “…feeding, haulout possibilities, and breeding.” (Jenssen, 2006, p. 78) Jenssen moves further to state that declining ice coverage will reduce the space for hunting seals for the polar bears. On one hand with a declining number of prays and on the other with reduced space for hunting they will have a less chance to catch a pray and that will eventually put a big question mark beside the survival of the specie. Furthermore temperature change is often associated with the juvenile survival rate of specie. (Jenssen, 2006, p. 78) However unlike others, apart from temperature rise in the Arctic, global climatic change and global warming as well as its possible impact on polar bears; Jenssen has also introduced POP (Persistent Organic Pollutant) and EDC (Endocrine Disrupting Chemicals). Particularly during the last four decades of the 20th century manmade persistent organic pollutant got transported to the Arctic through atmosphere. The source of such pollutant is far from the Arctic yet the Arctic has to endure its brunt. POP s has a much longer life since they are immune to “…physical, chemical and biochemical degradation…” (Jenssen, 2006, p.76) According to Jenssen owing to the fact that POP s and EDC are structurally similar; POP s can interact with hormone transport proteins and bestowed with the ability to disrupt hormone metabolism, it can imitate or obstruct the effects of endogenous hormones. It has also been observed that POP level is particularly higher in seals the main food source of polar bears. Though polar bears have a relatively better metabolism and excretion system for POP s even then the level of POP s is much higher in bears since they eat lots of seal blubbers. As referred by Jenssen POP s over all impact on cortisol level is negative and that might weaken a bear to effectively deal with other environmental stressors. (Jenssen, 2006, pp. 76-78) Moreover according to Jenssen THs, sex steroid hormones, and glucocorticosteroids are mostly affected from POPs in the Arctic mammals like polar bears. Sex steroid hormones are important for reproduction, glucocorticosteroids are important for immune system (“along with reproduction, behaviour, and adaptation to stress” (Jenssen, 2006, p. 78) and THs are important for Neuro development. It is obvious that any ill effect from POP on these variables will definitely lead the bear to further problem related with its survival. (Jenssen, 2006, p. 78) Jenssen’s findings are quite relevant since in recent times scientists have observed a poor immune system in polar bears and reduced rate of reproduction. (Gleason and Rode, 2009, p. 410) Jenssen has undertaken a systematic and logical approach to investigate the causes behind the destruction of the polar bear habitat. Another important reason behind the gradual reduction and a factor leading to the threat to survival of the polar bears emerges from the defence killing (of the polar bears) and trophy hunting activities carried out by the people visiting the arctic. On the other hand it is a risk to stay amongst such polar bears – “Living with large carnivores such as polar bears involves risks for people, and consequently for the wild species in question” (Freeman & Wenzel, 2006, p. 22) Sonne et al. (2007) have referred another important and alarming problem that is posing threat to already endangered polar bears. Apart from the global warming and POP s related EDC problem; mercury concentration in bear habitat is also a menace for the present and future survival of the specie. Each year around 200 to 300 tons of mercury makes their journey to The Arctic through atmosphere and large-scale ocean currents. The Arctic acts like a large sink continuously absorbing the global mercury discharge owing to the spring mercury depletion events. Mercury is a toxic material and absorption of mercury through food and atmosphere is a common problem in polar bear population. The study led by Sonne et al. reveals the fact that mercury found in polar bear’s kidney and liver is well into the toxic level. It has been rightly observed by the authors that infection prone polar bear population of East Greenland might be exposed to mercury poisoning and at least it’s a co factor among with others behind their declining health. (Sonne et al., 2007, pp. 2, 7) O’ Neil et al. (2008) rightly predicts a declining bear population in near future in The Arctic. This is in tune with the earlier studies referred in this article. Against a declining habitat reflected through melting and fragile ice this is most likely to happen in near future. Their findings regarding reduction of pray population and that of space for hunting also go in tune with the other studies. They have also rightly confronted the idea of polar bear hunting as a check to their population, since considering the present level of polar bear population and many dubious numbers against the exact number of polar bears, such a policy might lead to disastrous consequences for the specie. (O’Neil et. al., 2008, pp. 1650-1658) Tollefson has emphasized another important factor contributing to global warming and eventually to the melting of the Arctic. This factor popularly known as black carbon emerges from “incomplete combustion in diesel engines, coal power plants, agricultural burning and wildfires far to the south.” (Tollefson, 2009, p. 29) Swapped by the wind it reaches the Arctic and condensed to aerosol with other particles. Black carbon confines the energy of the Sun inside it and this eventually becomes a heating agent disturbing the Arctic environment. Many believe that it is the second most responsible agent for melting of The Arctic. However ambiguity prevails among the scientists and many still consider methane is more responsible than black carbon. Tollefson also highlights the fact that open air cooking in many countries of South East Asia like China, India. Pakistan and Bangladesh has serious contribution to this form of pollutant; as he refers Ramanathan “The lowly cooking stove may contribute about 40% of the black-carbon pollution in China and about two-thirds of the total in places such as India, Pakistan and Bangladesh, says Ramanathan.” (Tollefson, 2009, p. 32) However, Tollefson also refers him to conclude that it is hard to address this problem through any policy since it might bring forth serious political consequences. (Tollefson, 2009, p. 32) Conclusion: The environmental problem in The Arctic is mainly due to activities else where it’s a pure case of global pollutant emerging from anthropocentric activities. The polar bear of the Arctic is rapidly loosing their habitat and any recovery of that habitat is yet to be registered. If the resilience of the Arctic region breaks down then it might not come beck to the point of restoration forever. This will first put the bear population in a declining mood and then might even lead to extinct it. As referred by Hutchings “….the specie as a whole will decline by 30% or more over the next three polar bear generations.” (Hutchings and Bianchet, 2009, p. 49) The polar bear habitat is subject to many threats – global warming, POP and Mercury contamination, oil exploration, black carbon and hunting. Apart from the hunting all the others are directed towards habitat loss; the most striking problem for any specie. Though many initiatives have already been taken to restore or at least to stop any further degradation of the bear habitat; but the global atrocities on the Arctic land are yet to be addressed with proper international policy. If personal interest and unprecedented industrialization at the cost of the other animals is not stopped with immediate effect; soon the majestic bears of the Arctic will go beyond the veil of snow forever. References Freeman, M.M.R. and Wenzel, G.W. (March 2006). The Nature and Significance of Polar Bear Conservation Hunting in the Canadian Arctic, Arctic, 59(1), pp. 21–30. Gleason, J.S. and K.D. Rode (December 2009), Polar Bear Distribution and Habitat Association Reflect Long-term Changes in Fall Sea Ice Conditions in the Alaskan Beaufort Sea, Arctic, 62(4), pp. 405-417 Hoag, H. (2010). Arctic Ocean full up with carbon dioxide, Nature, available at: http://www.nature.com/news/2010/100722/full/news.2010.372.html (accessed on August 10, 2010) Hutchings, J.A. and M. Festa-Bianchet, (2009). Scientific advice on species at risk: a comparative analysis of status assessments of polar bear, Ursus maritimus, Environ. Rev. 17, pp. 45–51 Jenssen, B.M. (April 2006). Endocrine-Disrupting Chemicals and Climate Change: A Worst- Case Combination for Arctic Marine Mammals and Seabirds?, Environmental Health Perspectives, 114(1), pp. 76-80 O’Neill, S.J., Osborn, T.J., Hulme, M., Lorenzoni, I. & A. R. Watkinson (2008). Using expert knowledge to assess uncertainties in future polar bear populations under climate change, Journal of Applied Ecology, 45, pp. 1649–1659 Sonne, C., Dietz1, R. Leifsson, P.S. Asmund1, G., Born, E.W. & M. Kirkegaard, (2007), Are liver and renal lesions in East Greenland polar bears (Ursus maritimus) associated with high mercury levels?, Environmental Health, 6(11), pp. 1-9 Stirling, I. & Parkinson, C.L. (September 2006). Possible Effects of Climate Warming on Selected Populations of Polar Bears, Arctic, 59(3), pp. 261-275. Tollefson, J. (July 2, 2009). Climate’s Smoky Specter, Nature, 460, pp. 29-32. Towns, L. Deroch, A.E., Stirling, A. and N. J. Lunn, (2010), Changes in Land Distribution of Polar Bears in Western Hudson Bay, Arctic, 63(2), pp. 206-212. . Read More