"Grey's Anatomy" star Jessica Capshaw is the latest actress to join the Moms Clean Air Force campaign "to send a powerful message to Washington that there's only one way to keep poisons out of the air we breathe — and that's to create strong protections," she said. "It's time for moms to get the attention of political representatives and remind them that THEY bear a moral responsibility for cleaning poisons out of our air." Capshaw joins celebrity moms Julianne Moore, Christina Applegate, Maya Rudolph and Laila Ali in urging parents to pressure political leaders to support and protect the new Mercury and Air Toxic Standards ruling that will limit pollutants in our air. Watch the video here:

Tune in: Discovery Channel launches the ambitious seven-part series "Frozen Planet" on March 18. Four years in the making, it's an epic, comprehensive look at Earth's threatened polar regions, narrated by Alec Baldwin.

Cute alert! Nat Geo Wild's "Koala Hospital" takes you inside an Australian facility where volunteers care for sick and injured wild koalas. Documentarian Susan Kelly followed the lives of four koalas over three years for this special, premiering March 17.

Photos: Jason Roberts/Discovery Channel/BBC, Nat Geo Wild

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