Climate Change and Penguins - 2
WHAT IS HAPPENING TO THE PENGUINS?
Of all the penguins in the world, two kinds need to live in the areas of Antarctica where ice forms on the ocean: the small Adélie Penguin (4 kg or 10 pounds) and the large Emperor Penguin (25kg or 50 pounds). The lives of these penguins in some areas are being altered by changing climate.
On land, Adélies (Fig 1.) are quick, can jump from rock to rock, and climb very steep slopes easily. They build nests out of small rocks, especially those left behind by glaciers. They prefer areas to build nests that are not steep. In contrast, the Emperor (Fig 3.) is large, slow and clumsy. Instead of building a nest on land, one large egg is nestled on their feet and covered by a fold of skin on their lower stomach. Thus, Emperors raise chicks on flat frozen ocean that remains almost the whole year in coastal bays. They don’t need to climb at all.
Fig 1. Adélie penguin.
Fig 2. Adélie penguin feet. Good for climbing on ice and rock.
Fig 3. Emperor penguins
Fig 4. Fast ice and rock cliffs of Antarctica
Most of Antarctica’s coast is cliff-like and too steep or icy even for Adélie penguins. They need more gently sloping beaches to move out of the sea. Emperor Penguins don’t climb at all, so they form colonies on the frozen sea in places where the ice will not disappear until after their chicks are grown. These areas are very protected from the weather. That’s why the ice remains attached to the land. Therefore in the section of coast shown ifn Fig.4 Emperor penguins could form a colony but not Adélie penguins.
Fig 5. Antarctic continent and the USA
Fig 6. Sea ice breaking into ice floes
Fig 7. Adélie penguins resting on an ice floe.
Antarctica is larger than the USA and Mexico combined (Fig. 5), but the total amount of nesting space available for ALL the penguins could fit within the city limits of New York, Los Angeles or London.
In winter and early spring, the coldest time of the year, Antarctic seas freeze into a solid sheet, which from time to time is broken into pieces by the wind and waves. The pieces are called ice floes (Fig. 6). Penguins often hang out on ice floes (Fig. 7) when they’re not swimming. In winter the Adélies must move to where there is at least a few hours of daylight and open water between the ice floes in order to feed.
EMPEROR PENGUINS AND CLIMATE CHANGE
We know only a little about Emperor Penguins because they lay their eggs during the dark of winter. It is very difficult for people to see Emperor Penguins at this time, except with a very strong flashlight! Most Emperors live where there are at least a few hours of daylight or twilight each day; a few live so far south that the sun never rises for 3 months.
Fig 8. Emperor penguin colony from above.
Fig 9. Emperor chicks on the fast ice.
Fig 10. Graph showing decline in Emperor penguins at Pt Géologie. Data from Barbraud & Weimirskirch 2001, Nature
In Fig. 8, which is seen through the window of an airplane, you see clumps of Emperor Penguins that are nesting on the frozen sea. The icebergs are resting on the ocean bottom, about 100 m (300 ft) below. The icebergs remain there even for hundreds of years, and lock the sea ice in place long enough (7 months each year) for the chicks to grow up and depart before the ice melts. Sea ice that has been locked in place is called fast ice.
Emperors do not build nests but carry their egg and small chick on top of their feet in a large pouch formed by a fold of skin. A few weeks after hatching, chicks can stand on the sea ice but are protected from the cold by their parents (Fig.9). If the sea ice disappears before the chicks can take care of themselves they will be swept into the sea at too young an age for them to survive.
The Emperor Penguin colony where the movie “March of the Penguins” was filmed has been shrinking, as you can see in the above graph (Fig. 10). The colony (Pt Géologie) is located in northern Antarctica where temperatures have been steadily rising, and winds have been increasing. Also, humans built a bunch of buildings very close by, and the human activity bothers the penguins. Therefore, fewer and fewer young penguins have been returning to live in this colony. Recently, satellite imagery has shown that many have moved to a nearby section of coast where it won’t be so likely to blow away and where it is peaceful. One colony in the northernmost part of Antarctica has disappeared upon disappearance of the fast ice on which the colony had formed; satellite imagery found a new colony a bit farther south where there is still reliable fast ice. Most Emperor Penguins live in colonies located very far south where temperatures are still very cold, and fast ice remains. This could change, however, if global warming trends continue. One thing to the Emperor Penguin advantage is that by breeding on sea ice (fast ice), sea level rise will not initially be a bother.
ADÉLIE PENGUINS AND CLIMATE CHANGE
In some areas of Antarctica, warming temperatures are creating changes that benefit Adélie Penguins. In southern portions of the Antarctic coast, areas of once impenetrable pack ice have loosened allowing easier access by penguins. Penguins would much rather swim in the ocean than walk on sea ice that covers it. Up north, however, along the warmer Antarctic Peninsula, sea ice habitat that Adélies depend on is disappearing. These penguins exist only where there is sea ice for at least a portion of the year. Thus, in Antarctic Peninsula region, Adélie Penguins have been shifting south.
Fig 11. Adélie penguin breeding colony at Cape Crozier,
Fig.12. Parts of the Ross Ice Shelf floating on the water.
The colony at Cape Crozier (Fig.11) is located at the edge of a vast sheet of land ice, a glacier, sometimes 2 miles thick, which covers West Antarctica. Part of this sheet, called the Ross Ice Shelf, extends out from the land and floats on the sea just like ice floats in a glass of water (Fig 12). During the last ice age, when the northern and southern parts of Earth (the Polar Regions and more) were covered thickly by ice (glaciers), Adélie Penguins nested only in northern areas, as the Ice Sheet blocked penguins from nesting in many places where they nest today
Fig 13 shows the bay at Cape Royds completely covered by sea ice. This colony will disappear if the ice does not break into floes, forcing the penguins to walk too far to find open water and food for themselves and their chicks. As the Antarctic warms, however, the sea ice in these areas will become less extensive and the penguins will do well, at least until the sea ice disappears completely.
In Antarctica’s far south (Ross Island), where it is still cold (~-35C in winter, ~0C in summer), colonies have been growing. With warming temperatures and stronger winds, breaking apart the sea ice, penguins have easier access. The wind sweeps the coastal waters free of ice. The penguins are moving here because they can now swim rather than walk to find food, and bring more back to their chicks. Their food supply may be changing, too.
Fig 13. Bay at Cape Royds covered in ice.
Fig 14. Number of breeding pairs of Adélie Penguins at sites along the west side of the northern Antarctic Peninsula
In Antarctica’s far north, and particularly the west coast of the Antarctic Peninsula (Anvers Island and northward), air temperatures have become VERY warm, though still cold by human standards (temperatures similar to most ski resorts in winter). Warm enough, though, that if sea ice forms in winter — and winters of low sea ice extent are occurring with increasing frequency — it disappears much more quickly than 30 years ago. In other words, the ‘sea-ice season’ (the number of months when sea ice is present) is now three months shorter than it was 30 years ago, in fact only 3-4 months long. Antarctic penguins do not live well under such conditions, and each year fewer of them nest here, as is shown in the graph of Fig. 14. Young birds are recruiting to colonies farther south to where it is colder and there is still plenty of sea ice; in fact colonies in the southern Antarctic Peninsula are growing. Other kinds of penguins — ones who can not live where there is sea ice (chinstraps, Gentoos) — are moving south to replace the Adélie penguins.
Due to global climate change (see Fig. 15), sea ice off the coast of some parts of Antarctica (orange, red) has been disappearing (and so have the penguins). In other parts (blue) sea ice is becoming more open and increasing (and so have the penguins). Eventually, as temperatures continue to warm, Adélie Penguin colonies will disappear, leaving only their nest stones behind.
As modern humans continue to rely on fossil fuels, and to cut down forests, the Earth will most certainly continue to warm. Places like Antarctica or the Arctic will change the fastest, as more and more sea ice disappears. The white ice of these regions reflect sunlight directly back into space. For a while Adélie and Emperor penguins will be able to find new locations to make colonies. But, as they relocate farther and farther south they will eventually run out of room. By the time this happens, sea level will also have risen and eliminated even more of their habitat, except maybe for Emperor Penguins which form colonies on floating sea ice. But, New York, London, Amsterdam, Calcutta and many other human cities will be under water, too.
Fig 15. Penguin decline with sea ice reduction.
WHAT CAN I DO TO HELP PENGUINS?
What we do in our daily lives affects what happens to the penguins as well as other animals and plants that live on Earth. Every time we use electricity produced by fossil fuels or drive our car, or cut down a forest, we increase the amount of carbon dioxide in the air. Carbon dioxide is one of the gases in our atmosphere that absorbs heat, contributing to global warming and climate change. Here are some websites to explore for ideas on how you can help reduce the carbon dioxide you produce.
Fig 16. Adélie penguin mummy.
NOTE: While Earth’s warming temperatures are causing penguins to change their lives, so is the removal of fish and whales from the ocean. We have not included that part of the story here (it is included in the section for advanced grades). We thank the Antarctic programs (and their people) from France, New Zealand and the USA for some of the information in this presentation.
