The Arctic Ocean

The Arctic Ocean is the smallest of all the world’s oceans, and also the coldest, sitting entirely within the Arctic Circle. It is partly covered in surface ice throughout the year, and is almost completely covered in ice during the winter. Despite its barren surface, the Arctic Ocean is home to a plethora of marine lifeforms that are vital to the health of the world’s natural systems. The Arctic Ocean has increasingly become the subject of debate due to melting Arctic ice becoming a cause for concern in relation to climate change.

Light and Darkness in the Arctic Circle

It is a common misconception that the Arctic Circle experiences six months of unbroken daylight, and six months of complete darkness each year. The truth is a bit more complex than that. In Arctic regions, in addition to night and day there are three different types of twilight that can persist for hours at a time:

  • Astronomical Twilight: the darkest of the twilight phases, astronomical twilight occurs when the sun is between 12 and 18 degrees below the horizon. Unless obscured by clouds or light pollution, stars and other celestial bodies can still be seen in the night sky but there is a small amount of natural light.

  • Nautical Twilight: nautical twilight occurs when the sun is between 6 and 12 degrees below the horizon. During this phase, the sky is often dramatically lit up by peach, orange and red light towards the horizon, whilst it remains a deep blue higher up. This stage of twilight is so named because the brightest stars, used in navigation by sea, can still be seen.

The Siberian Coast in deep nautical twilight

  • Civil Twilight: this is the brightest of the twilight phases. The sun is only just below the horizon. It gets its name from the fact that there is enough natural light to carry out most outdoor activities. During this phase, the atmosphere scatters the sun’s rays, causing the sky to light up in bright oranges and yellows.

How much night, day and different types of twilight a location within the Arctic Circle experiences depends largely on its precise latitude. At certain places in midwinter, there may be no full daylight for many months on end. Instead, there is a very long night, broken up by just a few hours of twilight. During the summer, full daylight is almost constant for around three to four months.

The Arctic Ocean and Climate Change

Since 1979, the Arctic Ocean has lost on average 2.7% of its ice each decade. This might not sound like much, but it is – since records began in 1979, the Arctic has lost 1.36 million square kilometres of sea ice, which is an area roughly twice the size of Alaska. In this time, some areas have experienced more marked sea ice loss than others. For example, The Pechora Sea to the south of Severny Island is now virtually ice-free throughout the year. The amounts of ice lost in the summer are much greater than the rest of the year – the Arctic Ocean retains only about half the amount of ice in summer as it did in 1980, and that trend is set to continue, leading many leading scientists to predict that the Arctic Ocean will soon be completely ice-free in summer. This would have devastating consequences for all life on Earth.

The albedo effect: The white colour of Arctic ice reflects the sun’s energy back into space, limiting the effects of radiative warming. Once the ice disappears, the solar radiation is absorbed rather than reflected by the blue water, and this contributes to a warming planet.

Methane emissions: Much as permafrost under the Siberian Tundra releases trapped methane as it melts, so too does permafrost offshore, which contains large amounts of methane. Methane is a much more potent greenhouse gas than carbon dioxide, and the impacts of offshore methane release should not be underestimated.

The melting of the Greenland Ice Sheet: It is not only the water of the Arctic that is warming – air temperatures are also rising at an alarming rate. This is causing the Greenland Ice Sheet, which is the largest body of ice in the Arctic, to melt. The main effect of this is sea level rises, which put many of the world’s coastal cities at risk.

Oil Drilling in the Arctic Ocean

There is an estimated 35 trillion dollars’ worth of oil trapped below the Arctic Ocean in Russian territorial waters. The Russian Government has been very interested in extracting its wealth for decades, but until recently has been unable to, due to the severe engineering challenges posed by the extreme climate, and in particular the presence of sea ice.


Advancements in extraction technologies, combined with the retreating sea ice, has finally opened up the Arctic Ocean to oil exploration, although it remains prohibitively expensive.

In February 2020, the Russian Government announced ambitious plans to extract the Arctic Ocean’s oil wealth with multiple offshore drilling projects costing a total of $210 billion US dollars. You can read more about these plans here.

Methane escapes from Arctic waters

An icebreaker ship crosses the ice sheets

An Arctic oil drilling platform


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