Read the following context and choose the best option to answer the question.
Context: The Center for Biological Diversity awarded Alaska Governor Sarah Palin the 2008 Rubber Dodo Award . Governor Palin won the award for fighting the Department of Interior 's designation of the polar bear as a threatened species . The polar bear is threatened by a shrinking habitat due to global warming .
Question: How has global warming affected Polar bear habitats ?
Options: 
- El nino is a weather pattern caused by global warming that directly affects polar bears .
 - Global warming has affected weather patterns that cause severe storms in the southern hemisphere .
 - None of the above choices .
 - The melting of the ice caps has reduced the cold areas that polars require .


The melting of the ice caps has reduced the cold areas that polars require .