How does rising heat affect polar bears?


The ice-bear melts the clod from under his paws. As a result of global warming, the sea ice around the North Pole is disappearing, and faster and faster. This is due to the greenhouse effect, which is caused by the emission of carbon dioxide and other gases that are harmful to the climate.

In 1980 the Arctic Ocean was still frozen over 7.8 million square kilometers, an area about the size of Australia. Within 30 years the ice surface has shrunk to about half! The ice sheets are already thawing in spring. If it continues like this, the "eternal ice" will soon be completely gone.

This is a disaster for the polar bear. Environmental organizations fear that polar bears and seals will become extinct in the next 20 years. Migratory birds are also losing their breeding grounds in the Arctic due to the changed climate.

Another marine predator, on the other hand, is already finding a new habitat: Because the ice continues to recede, the killer whale can now also search for food high up in the north.

Short cut through the Arctic Ocean

The ice in the Arctic Ocean is melting dramatically. This has opened up a trade route between Europe and Asia: the Northeast Passage. This sea route runs along the north coast of the continents of Europe and Asia. In the past, large transport ships could only pass this route in midsummer. Because the Northeast Passage was frozen over most of the year and was much too dangerous because of the ice masses. Ships traveling between Rotterdam and Tokyo therefore took the long route through the Mediterranean, the Suez Canal and around India.

New satellite images show that the path through the Arctic Ocean is becoming more and more ice-free. This makes the journey easier for ships - even without an icebreaker. This saves time and transport costs, because the route through the Arctic Ocean is several thousand kilometers shorter than the old route through the Suez Canal.


The frozen soils of the Arctic are thawing faster than previously thought due to climate change. This could release huge amounts of the greenhouse gas methane into the atmosphere. That would additionally accelerate the warming of the earth.

Permafrost soils extend over huge areas in the northern hemisphere. They are mainly found in large parts of Siberia and Alaska. Their name comes from the fact that they are frozen all year round - at least so far. But the temperatures on earth are rising. For some years now, the frozen soils in the far north have been warming, starting to thaw and turning into huge swamps.

Scientists suspect that the thawing permafrost could accelerate climate change. Because the soils contain methane, a gas produced by microorganisms. This greenhouse gas has about 20 to 30 times more impact on the climate than carbon dioxide. In addition, large amounts of carbon are stored in the frozen ground. A devilish cycle begins here with rising temperatures: If the permafrost thaws due to climate change, methane and carbon dioxide are released into the air. The greenhouse gases warm the atmosphere, the earth heats up, the ice melts - and climate change is exacerbating itself.

So far, researchers have disagreed about how quickly the permafrost will thaw. The question of how many greenhouse gases are actually released has not yet been clarified.

Koala bear in climate change

Gloomy prospects for the koala bear: The cute marsupial is massively threatened by climate change. Because the greenhouse gas carbon dioxide makes the leaves of his favorite food inedible: eucalyptus leaves are turned down by the increasing CO2-Content in the air leathery and inedible. Because their nutrient content is reduced, the koala has to eat significantly more eucalyptus in order to be satisfied. This also applies to other marsupials and marsupials similar to them. Many other animal species are also directly at risk from climate change, especially in the polar regions. Ringed seals and emperor penguins are losing their habitat due to the receding ice. And the arctic beluga whale is finding less and less prey. What to do? The World Conservation Union (IUCN) emphasizes that the individual is not powerless. Everyone can reduce their carbon dioxide emissions and stand up for climate protection.


It is the mightiest of all Alpine glaciers: the Aletsch Glacier in the Bernese Alps is over 23 kilometers in length. Its ice cover is up to 900 meters thick. Still! Because the white splendor of the glaciers could soon be history.

For decades, researchers have observed that the ice masses are decreasing. They lose an average of half a meter in thickness every year. Climate change is to blame, which is causing temperatures on earth to rise: In the ever warmer summers, more ice melts than is added again in the cold season. The ice giant was particularly troubled by the hot summer of 2003: at that time, large parts of the glaciers had melted away. It is now even feared that the alpine glaciers could have disappeared in 30 years.

That would be a great loss for the landscape of the Alps - and a catastrophe for tourism: many winter sports locations make their living from ski areas on glaciers. When the ice and snow melt, tourists stay away too. In addition, there will be problems with the water supply when the glaciers die. Because huge amounts of fresh water are stored in their ice masses. Many places would then have to transport their drinking water expensively and from far away.

Cling film for glaciers

To protect their glaciers from rising temperatures, the Austrians have come up with something: they cover their glaciers with plastic cling film in summer. The almost four millimeter thick, white film is supposed to reflect the sun's rays and thus prevent ice and snow from melting. And indeed: Glacier researchers confirm that the film greatly reduces melting.

Glacier foils are now also being used in Switzerland and Germany. The Zugspitze now also gets a “sun hat” on a regular basis. Climate activists criticize that while this slows down the melting of the ice for some time, global warming cannot be stopped in this way.

Polar regions - Arctic and Antarctic

The largest ice sheets on earth are around the North Pole and the South Pole. Because of their special location, the polar regions receive very little sunlight and solar heat, and the summers are particularly short there. That is why it is always extremely cold there - temperatures of down to minus 70 degrees Celsius prevail all year round. The cold caused huge ice masses to form in the polar regions.

The ice of the Arctic around the North Pole covers a large part of the Arctic Ocean in winter. It then extends over an area of ​​several million square kilometers. For the most part, it is a layer of ice that floats on the sea. In addition, the Arctic ice covers the northern areas of Europe, Asia and North America.

On the other hand is the South Pole on a continent that Antarctic. Antarctica is the coldest place on earth. Their landmass is almost completely buried under an armor of ice and snow that is up to 4 kilometers thick. Almost three quarters of the fresh water on earth is stored in this ice.

People, animals and plants have adapted to life in the "eternal ice". Polar bears or reindeer, for example, protect themselves against the cold with a layer of fat and thick fur. The Antarctic is inhabited by only a few people, the Arctic is a little more populated. The most famous inhabitants of the Arctic are the Inuit in North America and Greenland, there are also the Lapps in northern Scandinavia and indigenous peoples in northern Siberia. They used to live there as nomads and get around with dog sleds. Today they use snowmobiles and many of them live in cities.

Hardly anything grows in the ice deserts around the poles because of the extreme cold. The ground between the polar regions and the cold-temperate zone is permanently frozen to a great depth. After the Latin word “permanere” for “to last”, this subsurface is also called permafrost. It only thaws a little a few months a year. Then particularly hardened plants such as mosses, lichens or dwarf shrubs can grow on it. This region around the polar regions is also called subpolar tundra.

The polar regions are the coldest areas on earth. It is precisely here that the earth is also heating up: For some years now, researchers have been observing that the ice masses of the Arctic and Antarctic are melting. The consequences of this warming cannot yet be precisely estimated. But it is already clear that many habitats are threatened by the melting of the poles.

The greenhouse effect

In a greenhouse, vegetables or flowers can thrive even when it's cold outside. That's because greenhouses are built out of glass. The glass - or a transparent film - allows the short-wave rays of the sun to enter the interior unhindered: the air warms up. On the other hand, the glass is impermeable to long-wave heat radiation, so the heat can no longer get out. That’s why it’s cozy and warm in a greenhouse.

Something similar is happening on a large scale on earth. The greenhouse gases carbon dioxide (CO2) and water vapor are naturally present in the atmosphere. Water vapor enters the air through evaporation, carbon dioxide through exhalation. Volcanic eruptions also contribute to the natural carbon dioxide content of the air. Both gases have the same effect as the glass in a greenhouse: They allow the short-wave rays of the sun to penetrate to the earth. At the same time, like an invisible barrier, they hinder the long-wave thermal radiation on its way back into space. The heat builds up and the atmosphere heats up.

Without this natural greenhouse effect, life on earth would hardly be possible, because it would be far too cold for most living things. Instead of the current average temperature of plus 15 degrees, it would be an icy minus 18 degrees Celsius. The surface of the earth would be frozen!

The problem starts when we increase the amount of greenhouse gases in the atmosphere. This is mainly done by burning oil, natural gas and coal. Heating the apartment, driving a car, burning garbage: all of these processes emit carbon dioxide. This CO2 has the largest share in the man-made greenhouse effect. But the cultivation of rice or cattle farming also intensify the effect: large amounts of methane (CH4) - also a greenhouse gas. In addition, nitrous oxide, ozone and fluorocarbons are among the greenhouse gases. Because all these gases slow down the earth's heat radiation, the temperatures on our globe continue to rise.

The consequences of climate change

Climate change is already clearly visible in the polar regions. Just a few decades ago, the Arctic Ocean was largely covered by ice. But this ice sheet is melting due to the rising temperatures: in the last 30 years its area has almost halved. At the same time, the ice layer is getting thinner and thinner. Climate researchers have calculated that the ice could melt completely in the next 20 years. The sea level would rise by a few meters as a result. But it's not just the ice sheets on the poles that are melting. The high mountain glaciers are also losing mass.

Because the sea level rises as the ice melts, ever larger coastal areas are flooded. Low-lying island states, such as the Maldives in the Indian Ocean or Tuvalu in the Pacific, are therefore increasingly threatened by storm surges. And not only the sea level, the water temperature also rises with climate change. As a result, more water evaporates and more water vapor is stored in the air. This increases the greenhouse effect, which further heats the atmosphere. This also increases the risk of severe weather such as heavy rain and hurricanes.

In arid regions, the deserts are spreading due to rising temperatures. More and more droughts are causing rivers to dry up and areas of land that were previously green wither. In the south of Spain, for example, the usual rainfalls, which are urgently needed for agriculture, have been absent for years. And the water shortage in southern Europe continues to intensify.

All of these consequences of climate change can already be observed. Climate researchers are trying to calculate how things will continue with the help of computer models. But the future is difficult to predict because so many influences determine our climate. The salty sea water is diluted with fresh water by the melting of the glaciers. However, the salinity of the sea drives the ocean currents. So what could happen if the warm Gulf Stream breaks off due to the lower salt content? Will it be colder instead of warmer in Europe? What would happen if the permafrost thawed in the far north? Do tons of the greenhouse gas methane then escape from the ground? And will this accelerate climate change?

So far nobody can answer that exactly. With all the unanswered questions, one thing seems certain: if we don't drastically reduce our carbon dioxide emissions, the temperatures on this globe will continue to rise.