Is the Arctic Ocean frozen?

Arctic Ocean

The ice is also less in winter: since the beginning of satellite measurements in 1978, the ice surface of the Arctic Ocean and its adjoining bodies of water had the lowest value to date at around 14 million square kilometers - the ice cover shrinks by 2.75 percent per decade in the arctic winter . At the same time, the ice thickness, which researchers have been studying for decades, is also decreasing. This in turn can lead to cracks in the ceiling, which favor climate change. Because: A thick ice cover reflects the sun's rays and protects the Arctic Ocean from warming. The open water between the clods stores much more heat than the ice. The water temperature rises - and in turn accelerates the melting process.

Higher water temperature

The Arctic Ocean covers an area of ​​more than 14 million square kilometers, almost the size of Antarctica. Although it is the smallest and at the same time the shallowest of the five great oceans in the world, the changes taking place here have a major impact on the global climate. The temperature of the Arctic Ocean at mean water depth has risen by 0.9 degrees Celsius per decade since the 1970s. In order to find out more about climate change in the Arctic, researchers have been tracking temperature changes in the Arctic Ocean for years. Politicians are also paying more and more attention to these developments: At the Paris Climate Conference (COP21) in December 2015, 195 countries passed the first universal, legally binding global climate agreement. The agreement envisages limiting global warming to well below 2 ° C. This is a particular challenge, especially in the Arctic.

Worldwide weather changes

By regulating the polar temperature, the sea ice also influences the weather worldwide. This is because the oceans and air act as motors that move heat to the poles to help maintain global equilibrium. One way is the large-scale movement of air. Another, slower method takes place underwater: Here ocean currents transport the heat along a "global conveyor belt".

Driven by local fluctuations in heat and salinity, this influences the weather at sea and on land. The shrinking of the sea ice has a major impact on this process. As cold as the Arctic Ocean is, it is still warmer than the air in winter. The sea ice thus serves as insulation. When it melts and breaks, it creates gaps that allow heat to escape from the Arctic Ocean.

Effects of warming: extreme weather and released methane gases

It is well known that global warming can increasingly lead to severe weather. The loss of sea ice can further accelerate this process in the Arctic. Continuous ice sheets usually limit the release of moisture from the ocean into the atmosphere. This makes strong storms more difficult to develop. When sea ice disappears or breaks up, storm formation is easier and waves can get bigger.
Last but not least, the greenhouse gas methane is released when the sea ice melts: The arctic tundra and sea sediments contain large, frozen methane deposits that pose a climate risk if this greenhouse gas is thawed and released due to changes in temperature.

Habitat is dwindling

The changes are also affecting living things in the Arctic: polar bears are losing their natural hunting grounds and newly settled species compete with long-established ones for food and habitat. Ice algae, which have so far formed a large part of the foodstuff for the Arctic ecosystem, are being deprived of their habitat in and under the ice - with an uncertain impact on the polar sea's food chain. And last but not least, humans are also affected by the changes when the fishing areas for edible fish change.

Fishing bans in the Arctic

However, commercial fishing is to be banned for at least sixteen years on an area of ​​2.8 million square kilometers around the North Pole. This was agreed by the European Union with Denmark, Norway, Iceland, Canada, China, Japan, South Korea, Russia and the USA at the end of 2017. Once the ten parties have ratified the agreement, it will come into force. Due to the expansion of the fish stocks in the Arctic Ocean and the decreasing ice surface, commercial desires could well be awakened again in the coming decades.

How fishing nets pollute the seas

The fishing ban also prevents another major problem: pollution of the Arctic Ocean. Because old fishing nets and other fishing accessories such as buoys or lines contribute to the fact that plastic waste ends up in the sea through incorrect disposal. Large ships - for example cruise ships or container ships - and human waste such as bags, bottles, buckets and other plastics also increase the amount of waste in the Arctic Ocean. Once the waste is in the water, it is seldom possible to assign it to the originator. In addition, the Arctic Ocean is considered a dead end: What is washed in here by various ocean currents does not come out of the ice masses again so quickly.

Caught in the vortex: garbage in the Arctic Ocean

The Arctic coasts are not so densely populated that their inhabitants alone could trigger the littering. Most of the plastic waste gets into the Arctic Ocean through large ocean eddies - the so-called garbage vortices that appear along the equator. There are currently five of these vortices. They arise because currents from the north and south meet in the oceans and bundle the garbage.

However, it is not just large plastic parts such as bags or bottles that float in the currents, but also much smaller particles - so-called microplastics. It often ends up in the wastewater and thus in the environment via cleaning agents such as shampoo or washing powder and when washing synthetic fibers. Up to 12,000 particles can be found in one liter of arctic sea ice. Plastic pollution is particularly dangerous for animals because they can swallow the small parts or get caught in larger plastic waste.

Sustainable handling required

But it's not just waste that puts a strain on the ocean's ecosystem. The loss of the ice surface means that shipping traffic along the Russian and Canadian coasts increases and tourist areas are opened up. As a result, the waste pollution of the Arctic Ocean is increasing and animals and people are also increasingly exposed to exhaust gases and noise. Challenges that locals, tour operators, tourists and representatives from business and politics alike have to face in order to protect the sensitive ecosystem over the long term.

Will the Arctic already be ice-free by 2050?

How fast the ice in the Arctic melts depends on many different factors such as air and water temperatures and ocean currents. In summer it goes particularly far back. Therefore, researchers can imagine finding an ice-free Arctic in the next 30 to 50 years in late summer. However, they assume that a large part of the sea ice will form anew in winter. In order to collect more precise data from the Arctic winter, scientists from 17 nations embark on a one-year expedition to the Arctic in September. The Multidisciplinary drifting Observatory for the Study of Arctic Climate (MOSAiC) project is intended to supplement and deepen the existing database on the interplay between the atmosphere, ice, ecosystem and ocean.