King Penguins -- the second largest penguins on Earth -- will likely see their populations plummet this century as the oceans surrounding Antarctica heat up.

Unlike the even heftier Empire Penguins, which live and breed in massive colonies on ice-covered Antarctica, King Penguins can only survive on cold, though ice-free islands. Their chicks don't have enough fat and plumage to survive icy environments.

But here's the problem: King Penguins eat fish, and as the oceans warm, these fish will move farther south, away from the ice-free islands. There aren't many islands around, so King Penguins can't just easily swim off to another home.

Consequently, the birds are projected to have to swim hundreds of miles farther to find fish. These energy-intensive, long-distance journeys will require them to consume their resources before they can return home and feed their mostly helpless chicks. The penguins will starve, argue the authors of a new study published Monday in the journal Nature Climate Change.

"It will be hard for one million penguins to relocate somewhere," said Emiliano Trucchi, an evolutionary geneticist at the University of Ferrara, in Italy, and an author of the study. "It's possible to migrate, but if they don’t find other islands that are suitable or [have] enough space, there will be losses."

These losses are projected to be dramatic. The studypredicts that, if greenhouse gas emissions continue at their present rates, 70 percent of King Penguins will either have to "abruptly" find new island homes by the end of the century or die.

It's assumed that many cold-adapted species will simply move farther south towards frigid Antarctica as Earth warms. But herein lies an insurmountable problem. Species can only go so far south before they run out of space.

"There is nowhere else to go -- that's the endpoint," said Trucchi. "It's like the mountains. You can go up, up, up, until you get to the top. Then you’re screwed."

And King Penguins can't simply go south. They must find ice-free islands that don't require swimming nearly 900 miles round-trip to find fish. Any further, and Trucchi and his team say the King Penguins will return home without fish for their chicks (they store the fish in their stomachs and regurgitate it for their young).

King Penguins rely upon cold, and nutrient-rich waters to rise up from the ocean depths, filling the surface waters with plankton and tiny shrimp-like krill to attract bounties of fish. This upwelling happens near a place called the Antarctic Polar Front -- where icy Antarctic oceans meet the warmer Atlantic. But as the oceans continue to warm (most of Earth's accumulating heat gets stored in the oceans), this fish-rich region is projected to move farther south, and farther away from the King Penguins.

"As long as temperatures are increasing, these areas of upwelling will keep moving toward the Antarctic," said Trucchi.

Their research, however, notes that some islands will likely be able to take on more King Penguins as the well-insulated birds are forced to leave their present colonies. Specifically, these islands include Bouvet Island, Heard, and South Georgia islands.

But this won't provide enough space for all the penguins alive today. So their numbers are expected to drop.

These projected losses are big, but the estimates will likely change as scientists observe how the planet responds to increased warming. The researchers based their projections on a "business as usual" scenario in regards to fossil fuel emissions, which assumes that today's emissions trends will continue.

So if nations can wean themselves off of oil and gas faster, and use increasingly cheaper renewable energies, perhaps the King Penguins will not be hit with such extreme declines.

If these trends continue, however, "This will be a catastrophic scenario," Trucchi said.

Scientists fully expect many Antarctic (and Arctic) wild populations to decline as their habitat warms. "In polar ecosystems, we know species will be more at risk from climate change," Trucchi said. "Most species have very peculiar adaptations to the cold."

What wasn't expected, though, is the rapidity of these changes, leaving little time for creatures like King Penguins to react, adapt, or find new homes.

"We didn’t expect it to happen so fast," said Trucchi.

（作者：汽车电瓶）