The Barents Sea stretches from Svalbard in the Arctic north, to the Norwegian and Russian mainland further south. For over 12,000 years, the North Barents Sea has had an Arctic climate. A cold surface layer of fresh water flows from the Arctic, covering warmer, more salty Atlantic water under it. This has effectively been protecting the Arctic waters from warming up.
However, it has for several decades been suggested that climate change may tip this balance. Now, there is observable evidence that this is happening. With decreasing amounts of Arctic sea ice, there is less icy cold water to form the cold cover, and the warmer Atlantic waters are rising to the surface.
This is a dynamic process – the more the two waters mix, the warmer the surface becomes; and as it becomes warmer, it facilitates more mixing. Thus, the North Barents Sea could soon be part of the Atlantic Ocean, and not the Arctic.
This warming of Arctic waters has profound implications for marine life. There are three species of whale that live year-round in the North Barents Sea, the bowhead, the beluga and the narwhal. As well, there are migratory visitors, for example the minke, humpback, blue and fin whales. These spend winter in warmer, low-latitude breeding grounds, and then migrate over 8,000 kilometres to cold Arctic waters in summer, to feed.
One whale affected by the warming Barents Sea is the humpback. This whale has previously been a rare sighting in Norway’s northern fjords. But the fish it preys on, for example cod and mackerel, are venturing further north into warming waters – and the whales that eat them are following.
Marine biologist, Kevin Ochoa, states: “There hasn’t been any study yet to show this, but it is clear that warming waters and melting ice are leading to them moving further north.”
It is feared that whales may not be able to adapt to large-scale effects of climate change, which threatens their food chain. The balance of predator, prey and food supply is under threat. In the case of the killer whale, their move further north could even endanger resident whales in extreme northerly waters.
With the warming of the Arctic seas, narwhals, beluga and bowhead whales they are at risk from the predatory killer whale, as it strays further north. Rebecca Kennedy, a Nature Canada blogger, says “Killer whales are poised to become a major Arctic predator.”
Narwhals in particular are threatened by the encroaching predators in less direct ways too. They have been observed to become stressed by the presence of killer whales which, they are aware, might eat them. The residents of Arctic waters are also threatened by the negative effect of warmer water on their habitat and its food resources, such as krill. Indirectly, the reduction of ice cover may lead to more commercial sea traffic and fossil fuel mining – which creates more pollution and potential for danger for whales.
It is of utmost concern for lovers of these sea-faring mammals, that our changing climate is not stacking up well them.