PLANET EARTH Ice Worlds

The stab wounds he received from the walrus are so severe that he can barely walk. The walruses are calm again seemingly aware that the injured bear no longer poses a threat to them or their young. Unable to feed this bear will not survive. If the global climate continues to warm and the Arctic ice melts sooner each year it's certain that more bears will share this fate.



At the southern end of our planet fiery ribbons are illuminating the winter skies. The aurora australis（极光）. This light brings no warmth to the male penguins who are still huddling defying the coldest conditions on the planet. Their ordeal（严峻考验） is drawing to a close. Thirty days after it last set the sun rises once more on Antarctica. Their appalling trials have all been for this.



Each father has just one meal left inside him. He's been saving it all winter. This single feeding will sustain the chicks for a few more days but the males have not eaten for nearly four months. If they do not eat soon they and their chicks will die. But there is hope on the horizon. The females are returning, and their bellies are full with fish. As they approach, waves of excitement ripple through the huddle.