The effects of global warming have caused humans to open their eyes to the ecosystems’ vulnerability as well the inhabitants housed there. The cause of global warming can be attributed to greenhouse gases (Robinson et al 2009). Greenhouse gases present in the atmosphere allow the Earth to remain warm by providing a blanket like cover. However since the nineteenth century humans have caused an increase in the production of greenhouse gases in the atmosphere due to the growing oil and coal economy (Robinson et al 2009). The increase in greenhouse gases as a result of burning fossil fuels is like throwing a second blanket on top of the Earth. Consequently, the increase in greenhouse gases causes an increase in temperature (Maxwell 1992). From the 1840 to the mid twentieth century the artic warmed to the highest temperatures it has seen in four centuries (Overpeck et al 1997). The average air temperature in the artic has increased 5 degrees Celsius over last 100 years (wwf). Another cause affecting global warming is deforestation. Trees act like a sponge absorbing carbon dioxide in the air however trees are continually cut in order to build towns. Cutting down the trees in essence increases the carbon dioxide levels in the air. As a result there has been a 20 % increase in CO2 levels in the atmosphere in the last twenty years (Arctic ecosystems in a ). In nature the climate system will fluctuate periodically but the critical point is that the baseline will continually be raised as the years go by. Polar bears (Ursus maritimus) live in the circumpolar Artic on top of packed ice, along or near coasts, and on islands. As of today scientists believe that there are around 22,000 polar bears around the world (Derocher 2004). A majority of... ... middle of paper ... ...ore fractured and labile, it is likely to move more in response to winds and currents so that polar bears will need to walk or swim more and thus use greater amounts of energy to maintain contact with the remaining preferred habitats.” Increasing temperatures in the Artic, toxic pollution, introduction of oil, and over hunting has lead to polar bears landing a spot on the endangered species list. If these factors are not reduced dramatically the species will become extinct. The effects of climate change are not constant they can shift dramatically in any instant. Therefore we humans can not measure and adequately predict the effects of climate change 100 percent. Behavior plasticity has been used to describe polar bears adaptively to climate change however with the increasing effects of greenhouse gases the bears will be unable to adapt leading to extinction.
The characteristics of the grizzly bear as a top predator also make it highly vulnerable to threats. Although it is an omnivore, because it relies heavily on salmon to make it through the winter, it is vulnerable to anything that impacts on salmon runs. It needs wide-ranging habitat and is slow to reproduce. As such, grizzly bears are considered not just a key species but also an ‘umbrella species’ because the protection of their habitats will result in an ‘umbrella of protection’ for a wide range of other species. The protected areas that have been set aside in the Great Bear Rainforest are not enough to sustain healthy populations of grizzly bear so it requires additional habitat set aside from logging. Trophy hunting of grizzly bears also continues to place their population at
People are responsible for higher carbon dioxide atmosphere emissions, while the Earth is now into the Little Ice Age, or just behind it. These factors together cause many years discussions of the main sources of climate changes and the temperature increasing as a result of human been or natural changes and its consequences; even if its lead to the global warming, or to the Earth’s cooling. In their articles, “Global Warming Is Eroding Glacial Ice” by Andrew C. Revkin and “Global Warming Is Not a Threat to Polar Ice” by Philip Stott, both authors discuss these two theories (Revkin 340; Stott 344). Revkin is right that global warming is taking place. Significant increase of carbon dioxide in the atmosphere is due to human activities combined with natural factors such as volcanic emissions and solar radiation – all together they lead to climate changes and temperatures rising. At the same time, other factors such as deforestation contribute to environmental changes for some glaciers not less than air pollution. However, during global warming not all regions of the planet are affected in the same way, local warming and cooling are both possible during these changes.
The Grizzly bear (Ursus arctos) has long been considered to be the symbol of the wild. They are beautiful, powerful and at the same time vulnerable animals. They are known to survive in remote areas not inhabited by humans. The Grizzly was once able to occupy most of the land from northern Mexico to Alaska and most places in between. With a disappearing natural habitat and one of the lowest reproduction rate of any mammal in North America the Grizzly bear has seen population number fall dramatically. Most Grizzly bears left in the continental United States are located in four states near Yellowstone National Park. Canada has Grizzly populations in five provinces. The state of Alaska has the largest population of these amazing animals. With change in habitat due to human involvement and low reproduction rates, Grizzly bears have had a hard time sustaining population numbers. This has caused them to virtually become non-existent in certain areas of North America and is forcing the bears that are left to move to more sufficient areas that can sustain their populations.
- Pagano, A. M., G. M. Durner, S. C. Amstrup, K. S. Simac, and G. S. York. 2012. Long-distance swimming by polar bears (Ursus maritimus) of the southern Beaufort Sea during years of extensive open water: Canadian Journal of Zoology 90:663-676. doi: 10.1139/z2012-033http://www.nrcresearchpress.com/doi/abs/10.1139/z2012-033#.UxOE1ZWPLoo
animals such as the polar bear, to mate and to prepare for the once again
In recent decades, the global warming threat has captured the attention of the nation and the world. While the main focus began with concentrating on the effects this long-term natural crisis would have on the human population, select groups have worked to approach the topic in a manner that entails prevention in order to help other animal and plant species around the globe. One such organization is the National Oceanic and Atmospheric Administration, which has played a major role in the conservation of the polar bear species, one of the mammals most adversely affected by the recent climate changes. As more research has been conducted regarding the polar bears, scientific name Ursus Maritimus, the conclusions have been shocking. In 2008, the Department to the Interior listed the polar bear species as “threatened” under the Endangered Species Act of 1973 awarding it some protections mandated by the federal government (Wolfe). However, on January 5, 2011, Representative Donald Young proposed a bill in Congress in order to delist the polar bears as threatened, thus decreasing and even removing the conservation efforts that have been set in place over the past three years. The polar bear Species should remain listed under the Endangered Species Act because ice thickness has decreased 40 percent during the past 30 years thus reducing the polar bears’ critical environment, if current conditions continue the polar bear populations around the world may decrease by two thirds by mid century, and since the species has been protected under the Endangered Species Act the worldwide populations have experienced stabilization or growth in most circumstances.
The grizzly bear, a kind of omnivorous animals who consume moose, fishes, “leaves, nuts, and seasonal fruits,” (Grizzly Bear) are “the largest of all bears in the world” (Grizzly Bear), particularly in Canada which primitively has “approximately 25,000” (Grizzly Bears) grizzly bears in British Columbia. Nonetheless, as a result of the hunting rush, the amount of grizzly bears as “majestic symbols of the wild” (Basic Facts About Grizzly Bears) plummeted by up to “15,075” (Grizzly Bears) in British Columbia in 2012. Meanwhile, in other ranges and countries, the number of grizzly bears had diverse degree of decrease so that grizzly bears were “designated, or listed, as threatened with extinction in 1975” (Grizzly Bears & the Endangered Species
Species are decreasing and becoming extinct over time due to climate warming. Animals and plants have developed and diversified from earlier forms to become more complex organisms. Not only have living organisms changed, but so has the Earth. Over time, the world itself has changed drastically, not just the climate but the way it looks as well. The ice on the arctic is melting, causing oceans to become more acidic, oceans became deserts and pollution from our everyday lives are affecting the ozone. It all adds up and changes the world negatively. When the world changes, so do the animals within it. Climate warming has been a big part of the change we see in the population of different species. The speed of climate change is excelling, which
In this report I will be using the Polar Bear (Ursus maritimus) as my chosen species. The Polar bear is the largest land living apex carnivore in the world where males can reach a mass of over 450 Kg and females between 150 Kg to 350 Kg. Instantly recognizable by their white fur coat which is technically transparent where it is the reflection of the snow that gives the Polar bear its beautiful white coat. As a Polar bear’s skin is black allowing for some heat from sunlight to aid in respiration. They are located all around the Arctic Circle. From Canada to Greenland to Russia, their range is vast due to the travelling they must endure to reach plentiful sources of food which is primarily seals however they have been known to hunt walrus and beluga whales.
Global warming has become a more prominent issue every decade since the mid 1900s. The increased temperatures are leading to substantial ice loss. This loss in ice is causing severe destruction to polar bear habitats and homes and is leading to their extinction. It also is affecting their food supply. Global warming is making it harder for polar bears to repopulate and is causing a decrease in the overall size of each bear. The chemicals associated with global warming are getting into the food chain and eventually into the polar bears themselves. Global warming is causing the extinction of polar bears in the arctic because it’s destroying their homes, decreasing their food supply, is affecting chemicals in the air and in their food, decreasing the average size of the bears, and contributes to a decrease in reproduction.
Analyzing polar bears’ life history will help lay a foundation for understanding why they are currently threatened. Currently there are about 22,000-31,000 polar bears found in 19 subpopulations across the globe (Wiig O et al., 2015). Polar bears have a “circumpolar distribution”: they generally live around the Arctic region around the North Pole, relying heavily on the Arctic ice for hunting, mating, resting, and creating dens (Gunderson, 2009). Their geographic range is determined by the level of ice in coastal areas which differs from summer to winter time. For example, during the winter, polar bears are more often seen at the southern edge of the ice pack versus during the winter they tend to stay on islands and coastal regions that retain ice on land. This heavy dependence on the level of sea ice makes them highly susceptible to global
A polar bear is a one of the eight species. “Scientists believe that the polar bear began over 200,000 years ago. They came from the brown bears ancestors.” Most experts think that polar bears are the longest bears. Males measure over 10 feet long, when standing on their hind legs, other bear not so much. Brown bears and polar bear are the largest and are both land carnivores. Polar bears are one of the worlds largest world predictors.
Most people do not think about global temperatures, but local ones. Therefore, climate change affects ecosystems, not just through increases in the mean, but also through changes in the extremes. Earth is already showing many signs of worldwide climate change. Even more, scientists are now able to say that climate change increases the risk of a particular weather pattern by a measurable amount and, in any case, that a particular episode is almost impossible to imagine without global warming.
Male Black Bears travel over many miles, sometimes living in an area as large as 60 square miles. Females do not roam as much and live in areas around 15 square miles. Male Bears do not live in the same areas as other males, but many females may live in the same areas. Females are more likely to defend their territory than a male is when an intruder is to enter. These animals determine their territory “by urinating, defecating, and by scratching, rubbing, and biting trees.” (State University of New York College of Environmental Science and Forestry, 2014) Most people think that bears live in caves, but bears lives in different places and make their dens out of different things. The dens may be in “open nest, brush piles, fallen trees, rock piles, excavations, hollow trees, and human structures.” (Ternant, 2006)
Polar bears are one species that are currently feeling the effects of a warming climate. Over the past twenty years, NA...