The possible addition of polar bears to the national list of protected species is encouraging.

Global warming is having a dramatic impact on wildlife and, as one of the signature species that attracts so much attention, the plight of the polar bears is helping to focus attention on it.

The protection is necessary because there are only about 100 polar bears in captivity in the United States and 20,000 left in the wild around the world.

The Interior Secretary announced recently that polar bears should be listed as threatened, which would give them federal protection under the Endangered Species Act. The Act is meant to protect species most likely to become extinct.

The measure would require the government to consider polar bears and their habitat when making decisions about the environment, like greenhouse gas emission policies.

A spokeswoman for the U.S. Fish and Wildlife Service said scientists will study polar bears for 12 months and make a recommendation based on the research to the Interior Department, which will decide whether to add them to the list. If bears go on the list, the government would be required to ensure anything it authorizes does not jeopardize the sea ice polar bears need to survive - which is considered an important step not only to protect bears, but also to stave off global warming.

There is still time to save polar bears but we must reduce greenhouse gas pollution immediately.

The bears are shrinking in size, there have been recent reports of cannibalism, more aggression and bears have drowned. These are the sorts of changes you usually see over hundreds of thousands of years, but it's happening quickly now.