Sarah Fretwell
Climate Change Impacts on Polar Bears Literature Review
Climate change impacting a Key Communicator Species- an Introduction:
Climate change is a global issue that is constantly being brought up and researched in the scientific community.. The evidence of climate change is unequivocal, an article done by NASA compiled a number evidence, these are some of the most compelling: Atmospheric carbon dioxide is the highest its ever been in the history of our planet-never being above 300 parts per million until the 1950’s, that rate of sea level riseing in the past decade is double that of the last centery, oceans have warmed 0.302 degress farenhight since 1969, ice sheets are shrinking
Greenland lost 36-60 cubic miles of ice per year between 2002-2006. With this amount of evidence that is being presented in the scientific community it is impossible to ignore the reality that is climate change. The effects of climate change is starting to take its toll. One species in particular has increased the discourse of climate change: the polar bear. The scientific community has turned this species into a key communicator of climate change. This literature review is an analysis of the research done on the effect that climate change is having on the polar bear and what the future may hold for the key communicator species.
Climate change affecting more than the temperature:
Popular science magazines such as National Geographic, have given narrative to animals for decades to show environmental issues (Whitley,2014). These animals contribute to and expand the public’s discourse on the topic making these species key communication species on the topic and add to the vulnerability of other species affected. One of these species that is well agreed on
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Sarah Fretwell in the scientific community is the Polar Bear. The polar bear is a species loved by many and that is what makes it a good symbol in showing the negative effects of climate change.
Polar bears inhabit artic sea ice and rely on it for everything including; feeding breeding and movement. The future forecast of artic sea ice as a result of climate change has given an idea of what the future looks like for polar bear population. Two different studies,one being a stochastic demographic analysis (Hunter,2010) and the other based off of expert knowledge (O’neill, 2015) using the relation between Artic Sea Ice and polar bear populations give an idea of what that future may look like
One analysis was done by combining demographic analysis, stochastic, environmentaldependent matrix population models with forecast of future sea ice conditions. Seeing an alarming decrease in the amount and avalibility of sea ice, the research projected a drastic decline in the polar bear population by the end of the 21 st century (hunter,2010).
A different research study took a survey of 10 expert opinions and used their expert knowledge to assess uncertainties in future polar bear population. The results of the assessment were the scientist projected that polar bear populations will undergo significant decline, possibly a 70% decrease in populations by 2050 reletice today. This projection was based off of maps and timeseries of sea-ice extent, the quantifying trends and variances surrounding climate change on polar bear populations, spreading to 2050 (O’Neill, 2015).
Based off of the results of these two studies, along with others, it is understood that climate change is causing artic ice to melt, reducing the amount and quality of sea ice avalibly to polar bears, the projected decline of the polar bear population. With this being known the next step is to find out what the ice melting is directly affecting within the species. This can be done though
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Sarah Fretwell research and learning everything we can about the species, something that scientist have already begun to do.
Variation in Polar Bear Response to Melting of Artic Ice:
Polar Bears are experiencing changes in the availability of their artic sea ice habitat. By comparing different polar bear populations the scientific community is able to get a better grasp on the amount of change needed to cause a change in the polar bears and exactly what is being effected in individual polar bears. These two studies look more in depth at what is changing with the polar bears that is causing a decrease in population.
Comparing two different polar bear populations, one in the Bering Sea , the other being in the
Beaufort sea, scientist were able to detect the responces of a top artic predator experiencing habiat loss. Scientist compared body, size, condition and recruitment of two polar bear populations with differing amount of melted artic sea- ice days, is was found that the less reduced ice day the better(Rode,2013).
The polar bear population in Bering Seas(CS) experience less reduced ice days than the population in Beau fort seas (SB), an ice day being the amount of days the polar bears have with ice.
The CS polar bears had higher reproduction rates and their recruitment was not reduced. In comparison to the SB polar bears had twice as many were found to be fasting in the spring, showed a decrease in size, reproduction rates and were in all over worse condition.
Polar bears use sea-ice throughout their entire life cycle, its main uses being for hunting and foraging. Female polar bears rely on the sea-ice to travel across the artic after giving birth.
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Sarah Fretwell
Looking at a change in population with any mammal it is important to look at how the issue proposed is affecting strictly the females. Research published in Polar Biology looked at shifts in female polar bear habitat use in East Greenland and found that over a multi-decadal loss of sea ice has resulted in shifts in polar bear habitat use in East Greenland.
The Scientist reached this conclusion by looking at sea ice data to quantify changes in sea ice freezing and breakings up, along with movement rates, area use, habitat selection, distribution and maternity denning data from female polar bears (Laidre,2015).
Conclusion:
It is proven that the polar bear population is being effected by climate change. The polar bear population had been projected to decrease by many studies, the polar bears affected are changing in size, fasting longer and even changing the way they are using their habitat.
While many studies have been done we need to improve our understanding on the pressure imposed by climate change and find how vulnerable polar bears are and to what extent they are going to be effect. More research needs to be conducted in order to make projection as accurate as possible.
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Sarah Fretwell
Sources
"Global Climate Change: Evidence." Climate Change: Vital Signs of the Planet . NASA. Web. 5
Aug. 2015
Hunter, Christine M., Hal Caswell, Michael C. Runge, Eric V. Regehr, Steve C. Amstrup, and
Ian Stirling. “Climate Change Threatens Polar Bear Populations: A Stochastic Demographic
Analysis.” Ecology 91.10 (2010): 2883-897.
Laidre, Kristin L., Erik W. Born, Patrick Heagerty, Øystein Wiig, Harry Stern, Rune Dietz, Jon
Aars, and Magnus Andersen. “Shifts in Female Polar Bear (Ursus Maritimus) Habitat Use in
East Greenland.” Polar Biology 38.6 (2015): 879-93.
Moritz, C., and R. Agudo. “The Future of Species Under Climate Change: Resilience or
Decline?” Science 341.6145 (2013): 504-08.
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Sarah Fretwell
O’Neill, Saffron J., Tim J. Osborn, Mike Hulme, Irene Lorenzoni, and Andrew R. Watkinson.
“Using Expert Knowledge to Assess Uncertainties in Future Polar Bear Populations under
Climate Change.” Journal of Applied Ecology 45.6 (2008): 1649-659.
Rode, Karyn D., Eric V. Regehr, David C. Douglas, George Durner, Andrew E. Derocher,
Gregory W. Thiemann, and Suzanne M. Budge. “Variation in the Response of an Arctic Top
Predator Experiencing Habitat Loss: Feeding and Reproductive Ecology of Two Polar Bear
Populations.” Glob Change Biol Global Change Biology 20.1 (2013): 76-88.
Whitley, Cameron Thomas, and Linda Kalof. “Animal Imagery in the Discourse of Climate
Change.” International Journal of Sociology 44.1 (2014): 10-33.
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