The stakes are high and the challenges to be met are just as important. The “One Ocean Summit” begins this Wednesday in France, and will be held until Friday, in the hope of giving a boost to several crucial international issues around the seas.
Requested by Emmanuel Macron, this summit is the first in a series of international events around the ocean: a UN meeting on the environment at the end of February which will address the issue of an international agreement on plastic, negotiations in March, still at the UN, on a treaty for the high seas, biodiversity and climate COPs and a UN conference on the oceans in Lisbon in June.
The NGOs hope for strong announcements, while regretting that issues as essential as overfishing are not on the agenda. Several associations, including France Nature Environnement (FNE), also intend to submit to French and European officials a petition signed by more than 460,000 people against the accidental captures of common dolphins, killed in fishing gear off the French coast.
Increasingly worrying temperatures
The question of the oceans is burning because the observation is alarming. Starting with the temperature, which has been rising steadily, and faster and faster, since the 1940s, and even more since the 1980s. data from the United States Oceanic and Atmospheric Observation Agency (NOAA), which record ocean temperature anomalies around the world, the year 2016 was particularly hot at the surface with a peak at 0.80°C above average.
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Yet the ocean is an essential link in climate and biodiversity. It plays an essential role in regulating the Earth’s temperature. “Its capacity to store heat is much more efficient than that of the continents or the atmosphere”, explained thus The world in 2015, recalling that “the ocean is the regulator of the global climate thanks to its continual exchanges with the atmosphere, whether radiative, mechanical or gaseous.”
A level that keeps increasing
Another worrying parameter for the planet: the level of the oceans. Because this rise in temperatures plays a role in the rise in sea level, in particular by the melting of the ice. Since 1993, the level has risen on average by 3.4 millimeters per year, or one centimeter every three years, with an increasingly rapid increase, according to the NASA satellite observations. Compared to the level of 1993, the oceans have therefore gained ten centimeters in almost thirty years.
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And the worst is yet to come. According to researchers from the Niels Bohr Institute, in Denmark, who have managed to quantify how quickly the sea will react to climate change, the forecasts are too conservative and the sea level is set to rise more and faster than scientists thought. Martin Siegert, researcher at Imperial College London explained in 2020 in a communicatedthat for a warming of the planet’s temperatures of 4°C by 2100, he foresees a rise in sea level of between 0.61 and 1.10 meters, minimum.
Rising sea levels have direct repercussions on populations living in coastal areas. Which will then be more prone to flooding. But it also upsets the entire marine ecosystem.
From polluted oceans to microplastics
Marine fauna and flora also suffer from pollution, particularly that of primary microplastics, those that enter the ocean in the form of small particles from domestic and industrial products.
Sometimes these polluting wastes are unexpected. So, according to international union for conservation of nature (IUCN), the main microplastics found in the oceans come from synthetic textiles (35%). The latter release large quantities of plastic fibers into the washing water.
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Just behind, we find 28% of microplastic waste from car tires, because of their wear on the roads. “Primary microplastics can be intentionally added to products, such as certain exfoliating agents incorporated into cosmetics (shower gels, creams, etc.) or they can result from the abrasion of larger plastic objects during their manufacture. , their use or maintenance, such as the wear of tires on the roads or that of synthetic textiles during washing”, explains the IUCN.
More or less biodegradable waste
In addition to primary microplastics, other waste, more or less biodegradable, invites itself into the depths of the ocean. Among them, many everyday objects, such as cigarette butts, which can take a year and a half to ten years to biodegrade, according to thewoods hole institute of oceanography (WHOI).
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The WHOI has also calculated the time it takes a plastic bag to disintegrate in the oceans: twenty years. And this duration can go up to 600 years, concerning the fishing nets. For a plastic bottle, we count 450 years, as for a disposable diaper.
Countries that pollute more than others
A large amount of plastic found in the oceans is the result of poor waste management by countries. Among the worst students, China comes far ahead, according to the estimates of a study by the wall street journal published in 2015, followed by Indonesia. The two countries are thus responsible for nearly 5 million tonnes of plastic debris that end up at sea each year.
WWF is sounding the alarm. In a statement published on Tuesday, the NGO estimates that “if global plastic production does indeed double by 2040, as projections claim, the amount of plastic debris in the oceans will have quadrupled by 2050” .
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“At this rate of growth, plastic pollution will cause significant ecological risks in many marine areas, warns the organization. Some ‘plastic pollution hotspots’, such as the Mediterranean, East China Sea and Yellow Sea, or the Arctic sea ice, already exceed the ecologically dangerous threshold of concentrations of microplastics.
On the other hand, this plastic pollution does not disappear over time. According to Heike Vesper, director of the marine program of WWF Germany, quoted in the press release, “everything suggests that the contamination of the ocean by plastic is irreversible. Once distributed in the ocean, plastic waste is almost impossible to recover. They degrade steadily and therefore the concentration of micro and nanoplastics will continue to increase for decades. Tackling the causes of plastic pollution is far more effective than cleaning up afterwards.”