THE DETRIMENTAL EFFECTS OF CLIMATE CHANGE ON POLAR BEAR POPULATIONS1
The Detrimental Effects of Climate Change on Polar Bear Populations
Alex Cowan
Sheridan Institute
Table of Contents
Abstract
The Detrimental Effects of Climate Change on Polar Bear Populations
Background
Effects of Climate Change on the Arctic and the Polar Bear Population
Human Influence on Climate Change
Human Responsibility to Protect Arctic Wildlife...... 7
Conclusion
References...... 9
Abstract
The purpose of this report is to focus on human responsibility for climate change and the results on the polar bear population. This report explains the effects of climate change on polar bear populations. It affirms that the warming climate will lead to the erosion of the polar bears’ habitat and ultimately to their extinction. The report identifies environmental issues caused by man and their consequences. Furthermore, this report emphasizes the importance of human action in preserving Arctic wildlife.
Research for this report was collected from online journal articles and government websites.
The Detrimental Effects of Climate Change on Polar Bear Populations
The Canadian government defines climate change as a long-term shift in weather conditions identified by changes in temperature, precipitation, winds, and other indicators (2012, para. 1). The government states that the causes of climate change are both natural and human (2012, para. 2−3). Climate change is causing Arctic temperatures to rise and remain elevated for longer periods, resulting in melting sea ice and the erosion of polar bears’ natural habitats.
Background
Currently Arctic temperatures are on the rise and remain elevated for longer periods of time, evident in the sea ice formation and breakup. The sea ice is now forming later in the winter season and is melting sooner in the spring. The Arctic Ocean's ice cover reached a record low this summer and long-term trends predict that the Arctic will soon be ice-free for the first time in millions of years (Emerson, E., 2012). This disruption in the environment directly affects the polar bears habitat, feeding and mating patterns.
Effects of Climate Change on the Arctic and the Polar Bear Population
As the atmosphere in the Arctic warms, the snow and ice melt cause a rise in sea levels and a reduction of land mass. According to Andrew Derocher “the projected loss of polar bear sea-ice habitat as a result of a warming climate will dramatically reduce the spatial and temporal extent of that habitat by the end of the twenty-first century” (2010, para. 1). With global warming causing the sea ice to freeze later in the winter and melt sooner in the spring, the polar bears have a minimized habitat. The bears now have less space to roam, causing the population to be more condensed.
The early sea-ice breakup is limiting access to major seal populations, which are the bears’ main food source. The bears require high fat diets and can feed on walrus and beluga as well, but since they are also ice-associated prey, they too are hard to access (Peacock, Derocher, Thiemann, Stirling, 2011). With decreased nutrition comes a string of other problems including starvation or resorting to cannibalism, particularly males feeding on young cubs. If polar bear cubs are hunted as food, the future bear populations will ultimately be depleted.
The bears' mating season is disrupted by the changing climate. Derocher mentions that there has been a slow decline in polar bear populations along the Hudson Bay "due to the lower survival and reproduction that is correlated with reduced sea-ice duration" (2010, para. 3). As well, he states polar bears have low reproduction rates and even if there is recovery after loss of sea ice, the change will still have serious effects on the bear population (2010, para. 3−4).
Human Influence on Climate Change
Human activity plays a large role in climate change through the way we live our everyday lives. For years, the human population has been driven to find the most efficient way to fulfill our wants and needs. However, discovering the quickest way to meet our needs has lead us to overlook the environmental hazards that result from our actions. Over time humans have sacrificed health and clean environment for productivity and efficiency.
The Canadian government states "the overall effect of human activities since the Industrial Revolution has been a warming effect, driven primarily by emissions of carbon dioxide and enhanced by emissions of other greenhouse gases" (2012, para. 4). The Canadian government also believes that if we continue to produce consistent amounts of greenhouse gas, the planet may heat up to levels that have never been experienced before (2012, para. 4−6). If this warming trend continues, the Arctic climate will change and the current ecosystem will be drastically altered. This leaves the prospects for polar bears fairly grim since they are biologically built to live in a cold climate.
Another human influence on climate change has been the production of harmful chemicals such as POPs, persistent organic pollutants, which are found in pesticides and in industrial waste. Most of these pollutants are released into the atmosphere in the more central regions of the world and they are turning up in the Arctic by way of northward atmospheric transport. However the ocean and wind currents naturally stream northward, carrying all the pollutants to the Arctic.
These POPs are turning up in the fat tissue of polar bears because of bioaccumulation. Studies are showing that these POPs are causing a reduction in the polar bears’ bone mineral density and are causing birth defects, such as malformed sex organs (Air/Water Pollution Report, 2001; Tenenbaum, 2004). POPs have been banned in most countries, so they are no longer being released into the atmosphere. This change will not reverse the damage that’s already been done, but it will help preserve the future generations of polar bears.
Human Responsibility to Protect Arctic Wildlife
"To work in the fields of polar bear ecology, conservation, and management in a rapidly changing world requires optimism about humans’ ability to reduce the levels of greenhouse gases that threaten the persistence of polar bears and their ecosystems" (Peacock et al., 2011).
The effects of climate change on the Arctic are causing great stress on the polar bear population. It is our responsibility to protect this threatened ecosystem. We must do everything we can to reverse the damage we have caused. People need to do their part in finding ways to reduce the amount of pollution being released into the atmosphere. By being more conscious of how we are influencing our surrounding ecosystem, we can slow the effects of climate change.
The Canadian government has implemented the federal Species at Risk Act: "The purposes of this Act are to prevent wildlife species from being extirpated or becoming extinct, to provide for the recovery of wildlife species that are extirpated, endangered or threatened as a result of human activity and to manage species of special concern to prevent them from becoming endangered or threatened" (Species at Risk Act, 2002). This Act is a good start to the preservation of polar bears, but we all must do more.
Conclusion
The evidence is clear that climate change is causing Arctic temperatures to rise, and as a result the polar bear population is being negatively affected. Through study and analysis of the polar bear population, it is obvious that they are already experiencing difficulty surviving in the warming climate. With the sea ice forming later in the winter and melting earlier in the spring, the bears are losing their habitat and access to their main food source. It is evident that humans have played a role in the cause of global warming through our excess production of greenhouse gases and release of harmful chemicals into the atmosphere. As humans are part of the cause of the deterioration of the Arctic ecosystem, it is our duty to help slow the effects of climate change through the reduction of greenhouse gas emission going forward.
References
Derocher, A. E. (2010). The prospects for polar bears: Is the polar bear doomed to extinction? Nature, 468.7326. Retrieved from
Emerson, E. (2012). Shrinking ice in the Arctic offers an uh-oh moment. Science News. 182.7. Retrieved from
Government of Canada. (2012). Causes of climate change. Retrieved from
Government of Canada. (2002). Species at Risk Act. Retrieved from
O’Neill, S. J., Osborn, T. J., Hulme, M., Lorenzoni, I., & Watkinson, A. R. (2008). Using expert knowledge to assess uncertainties in future polar bear populations under climate change. Journal of Applied Ecology, 45, pp. 1649−1659. doi: 10.1111/j.1365-2664.2008.01552.x
Peacock, E., Derocher, A. E., Thiemann, G. W., & Stirling I. (2011). Conservation and management of Canada’s polar bears (Ursus maritimus) in a changing Arctic. Can. J. Zool, 89, 371-385. doi: 10.1139/Z11-021
Researchers consider link between POPs and polar bear abnormalities. (2001). Air/Water Pollution Report.39.21. Retrieved from
Tenenbaum, D. J. (2004). POPs in polar bears: Organochlorines affect bone density. Environmental Health Perspectives. 112.17. Retrieved from