From the freezing Arctic waters to the tropical Caribbean or the warm Mediterranean, seas and oceans around the world face the same problems of biodiversity destruction, contamination and overexploitation that the Climate Summit (COP25) will try to address with concrete measures.
Despite the immensity of the surface covered by marine waters, almost 70% of the planet, the balance is increasingly difficult, with increasing risks, such as rising levels and temperatures, which reached record numbers in 2018, according to data from the World Meteorological Organization.
Evidence of the fragility of these ecosystems is the recent ecological catastrophe of the so-called Mar Menor, part of the Mediterranean located in southeastern Spain, where in October tons of dead fish appeared after torrential rains.
Sediment and organic remains
The combination of freshwater and the indiscriminate dumping – for decades – of sediment and organic debris from intense agriculture with a heavily urbanized coastline has collapsed flora and fauna, after literally leaving them without oxygen, and turned the area into a more "sea". than dying, "according to the definition of Jordi Camp, a researcher at the Spanish Institute of Marine Sciences-CSIC.
The Mediterranean is one of the most vulnerable seas to the climate crisis and, according to the United Nations Food and Agriculture Organization (FAO), the most over-exploited in the world: its only exit is the Straits of Gibraltar, between Spain and Morocco. natural enough to mitigate the negative effects of the weather and is surrounded by intense human activity.
Institutions such as the Union for the Mediterranean or the United Nations Environment Program (UNEP) have warned that their basin has experienced a temperature rise of 1.5 degrees Celsius from the preindustrial era and predict that in the In the coming years, more and more hot flashes will come, drier as well as more torrential rain, which will have serious socioeconomic and environmental effects.
In cases such as the Arctic, warming should not, in principle, be so negative, as reducing ice would improve shipping lanes and facilitate exploitation of natural resources, but this could lead to conflicts over control of these resources.
Russian President Vladimir Putin warned that the development of this region, where 40% of the population is Russian, is already a priority for the state and part of its geostrategic development plans. In 2014, Moscow created the Northern Fleet Unified Strategic Command to secure and protect its presence in the region.
Climate change will also bring other problems, such as the melting of permafrost, the permanently frozen soil layer on which buildings, roads and infrastructure are built which, due to softening of the soil, will be seriously damaged or even destroyed.
Other cold seas, such as the North and the Baltic, suffer from heavy metal contamination, maritime traffic pollution, predatory fishing and the excessive presence of wind farms and oil rigs that, according to the International Council for the Exploration of Mar (ICES), put species such as cod on the verge of collapse.
Nor can we forget about eutrophication, which causes the proliferation of algae – which deplete oxygen – and invasive species that, thanks to a less cold climate, become able to settle in the ecosystem and displace local species.
Warmer seas such as the Caribbean have similar pollution problems: faecal coliforms, plastics, agricultural and chemical residues, and oil spills are disrupting a low nutrient ecosystem that has so far survived in fragile equilibrium, but is very threatened.
This is the case, for example, of corals, which suffer from the disease known as the "white syndrome", which in Mexico alone destroyed about 40% of this population.
Paradoxically, these same circumstances accelerate the development of other species, such as algae, which can create true floating islands of up to thousands of square kilometers that seriously affect ecosystems as they cover the sun and reduce light and oxygen levels, harming fish. and corals.
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