The polar oceans are amongst the least understood environments on Earth. They respond to global temperature change; absorb heat and carbon from the atmosphere; they accommodate millions of seabirds, whales and fish; and provide food for a hungry world. They also keep our planet cool and supply other oceans with nutrients. However, because of their remoteness and inhospitable environment, data coverage is extremely rare.
International research has shown that the polar oceans are changing, and in many areas the rate of that change is accelerating. In the Arctic, there is evidence that heat, freshwater and energy are changing rapidly and with increasing regional variability. This has an impact on global circulation and distribution of nutrients and carbon dioxide, and subsequently affects the marine life.
In addition, the polar oceans are warming up. In fact, summer surface temperatures in large parts of the Arctic Ocean are 2 - 3°C warmer than the 1982 - 2010, while there has been a reduction in summer sea ice extent from about 7 million square kilometres in the late 1970s to around 4 million square kilometres in 2017; a reduction of nearly 50%.
In addition, oxygen levels in the world’s oceans have decreased by two% in the last 50 years, but this trend is more prevalent than in the Arctic Ocean. Reduced oxygen in Arctic seawater will impact fish stocks, causing fish to grow more slowly, reach smaller sizes, and produce fewer offspring. This will impact the food chain, affecting both fisheries and the indigenous and local communities who source their food from the seas.
Of course, plastics would not be absent. A Norwegian study recently found up to 234 microplastic particles in a single litre of melted Arctic sea ice. Once these particles enter the seas they are ingested by sea creatures who mistake them for food. The long-term effects of microplastics are uncertain, but scientists are starting monitoring programmes of plastic levels in both polar oceans, and are working to understand the effect of this increase of plastic waste on polar ecosystems.
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