An experts report released today has confirmed that the sea level continues to rise, at an alarming rate of 3.1 millimetres per year, due to global warming and the melting of ice on Earth. The extent of Arctic sea ice has been steadily decreasing, between 1979 and 2020 it has lost the equivalent of six times the size of Germany.
More than 150 scientists from around 30 European institutions collaborated on the work. According to the findings, the ocean is undergoing “unprecedented changes”, which will have “a huge impact” on human well-being and marine environments.
The extreme variation between cold spells and heat waves in the North Sea is related to changes in the catch of sole, European lobster, sea bass, red mullet and crabs.
Pollution from onshore activities such as agriculture and industry is having an impact on marine ecosystems, stressed experts in the fifth edition of the report on the state of the oceans.
Warming oceans and rising salinity have intensified in the Mediterranean over the past decade.
"The warming of the Arctic ocean is estimated to contribute nearly 4% to global warming in the oceans," the report reads.
“Sea surface and subsurface temperatures are rising around the world and sea levels continue to rise at alarming rates: 2.5 mm per year in the Mediterranean and up to 3.1 mm per year globally,” the experts wrote.
The document is presented as a reference for the scientific community, decision makers and the general public.
The combination of these factors can cause "extreme events" in more vulnerable areas, such as Venice, where in 2019 an unusual rise in water levels, a strong tide and extreme weather conditions in the region caused the so-called "Acqua Alta" - when the water level rose to a maximum of 1.89 metres. “This was the highest water level recorded since 1966 and more than 50% of the city was flooded,” the document's authors recalled.
Scientists also explained that nutrient pollution from land-based activities such as agriculture and industry has “a devastating effect on water quality” in the ocean.
Through eutrophication, increased plant growth can lead to reduced oxygen levels in seawater and even block natural light, “with potentially serious effects” on coastal environments and marine biodiversity.
In the Black Sea, for example, the percentage of oxygen has been decreasing since the beginning of measurements in 1955.
The warming of sea water causes some fish species to migrate to cooler waters, leading to the introduction of non-native species in a certain habitat, as happened in 2019 when the lionfish migrated from the Suez Canal to the Ionian Sea, due to to rising temperatures in the Mediterranean Basin.
According to the report, Arctic sea ice remains far below average and is decreasing "at an alarming rate".
Over the past 30 years, Arctic sea ice has steadily decreased in extent and thickness. Since 1979, ice cover in September has reduced 12.89% per decade, with record lows for the past two years.
Continued loss of Arctic sea ice could contribute to regional warming, erosion of Arctic coasts and changes in global weather patterns.
