Thin Ice written by Susan McGrath explains the negative effects of global warming on polar bears. Greenhouse gases released into the atmosphere are making the earth warmer. The ice on which polar bears live continues to shrink due to rising temperatures. In 1979 there was about 30% more ice in the summer than today. Polar bears spend almost their entire lives on sea ice (McGrath). The only time they go to land is to build maternal dens. After birth, the calf and mother must swim back onto the ice. As the ice is melting, the distance polar bears swim continues to increase. Polar bears are skilled swimmers, but these long swims can be fatal. A tracker on a mother polar bear showed that she and her cub had to swim 427 miles to reach the ice. The cub died during the swim (McGrath). Melting ice is also causing polar bears to become thinner. Polar bears' weight loss is caused by the long swims they have to do to reach the ice. Losing weight has a negative effect on their health. Declining health causes polar bears to reproduce and fewer cubs survive. Polar bears aren't getting that big anymore (McGrath). Because they aren't that big, they can't catch as much food. When males are hungry and malnourished they can turn into cannibals. They kill cubs and sometimes females for food (McGrath). The question that arises is: will polar bears be able to survive if temperatures continue to rise? Scientists believe they would be able to survive in the short term, but after a few years of not being able to live on the ice they would die. The death of polar bears will completely change the ecosystems they live in... middle of paper... I would have thought that the average temperature would have increased much more to have all these negative effects. Rising temperatures in an icy and snowy area are especially harmful. This is because ice and snow reflect most of the sun's rays while water absorbs most of the rays. Then, as ice turns into water, the water will continue to warm and melt more ice. Overall, I really liked the article and found it interesting. It's scary to think about the effects we are having on the environment. Humans will have to start making a conscious effort to change the amount of greenhouse gases put into the environment. There are many different ways you can get involved in helping the environment. Making a conscious effort and changing a bad habit makes a difference. Humans must be the custodians of the earth and not those who destroy it.