Rezo

Le portail des copains

    • C’est le texte le plus dérangeant et puissant que j’aie lu de la semaine, notamment parce que ça nous dit où en est le capitalisme vis-à-vis de l’exploitation de la nature : c’est toujours open bar, la course à l’innovation technique mais en version pseudo-verte.

      Many people imagine the seabed to be a vast expanse of sand, but it’s a jagged and dynamic landscape with as much variation as any place onshore. Mountains surge from underwater plains, canyons slice miles deep, hot springs billow through fissures in rock, and streams of heavy brine ooze down hillsides, pooling into undersea lakes.

      At full capacity, these companies expect to dredge thousands of square miles a year. Their collection vehicles will creep across the bottom in systematic rows, scraping through the top five inches of the ocean floor. Ships above will draw thousands of pounds of sediment through a hose to the surface, remove the metallic objects, known as polymetallic nodules, and then flush the rest back into the water. Some of that slurry will contain toxins such as mercury and lead, which could poison the surrounding ocean for hundreds of miles. The rest will drift in the current until it settles in nearby ecosystems. An early study by the Royal Swedish Academy of Sciences predicted that each mining ship will release about 2 million cubic feet of discharge every day, enough to fill a freight train that is 16 miles long. The authors called this “a conservative estimate,” since other projections had been three times as high. By any measure, they concluded, “a very large area will be blanketed by sediment to such an extent that many animals will not be able to cope with the impact and whole communities will be severely affected by the loss of individuals and species.”

      Scientists divide the ocean into five layers of depth. Closest to the surface is the “sunlight zone,” where plants thrive; then comes the “twilight zone,” where darkness falls; next is the “midnight zone,” where some creatures generate their own light; and then there’s a frozen flatland known simply as “the abyss.” Oceanographers have visited these layers in submersible vehicles for half a century, but the final layer is difficult to reach. It is known as the “hadal zone,” in reference to Hades, the ancient Greek god of the underworld, and it includes any water that is at least 6,000 meters below the surface—or, in a more Vernian formulation, that is 20,000 feet under the sea. Because the hadal zone is so deep, it is usually associated with ocean trenches, but several deepwater plains have sections that cross into hadal depth.

      The ISA has issued more mining licenses for nodules than for any other seabed deposit. Most of these licenses authorize contractors to exploit a single deepwater plain. Known as the Clarion-Clipperton Zone, or CCZ, it extends across 1.7 million square miles between Hawaii and Mexico—wider than the continental United States. When the Mining Code is approved, more than a dozen companies will accelerate their explorations in the CCZ to industrial-scale extraction. Their ships and robots will use vacuum hoses to suck nodules and sediment from the seafloor, extracting the metal and dumping the rest into the water. How many ecosystems will be covered by that sediment is impossible to predict. Ocean currents fluctuate regularly in speed and direction, so identical plumes of slurry will travel different distances, in different directions, on different days. The impact of a sediment plume also depends on how it is released. Slurry that is dumped near the surface will drift farther than slurry pumped back to the bottom. The circulating draft of the Mining Code does not specify a depth of discharge. The ISA has adopted an estimate that sediment dumped near the surface will travel no more than 62 miles from the point of release, but many experts believe the slurry could travel farther. A recent survey of academic research compiled by Greenpeace concluded that mining waste “could travel hundreds or even thousands of kilometers.”

      https://storage.googleapis.com/planet4-international-stateless/2019/06/f223a588-in-deep-water-greenpeace-deep-sea-mining-2019.pdf

      Building a vehicle to function at 36,000 feet, under 2 million pounds of pressure per square foot, is a task of interstellar-type engineering. It’s a good deal more rigorous than, say, bolting together a rover to skitter across Mars. Picture the schematic of an iPhone case that can be smashed with a sledgehammer more or less constantly, from every angle at once, without a trace of damage, and you’re in the ballpark—or just consider the fact that more people have walked on the moon than have reached the bottom of the Mariana Trench, the deepest place on Earth.

      While scientists struggle to reach the deep ocean, human impact has already gotten there. Most of us are familiar with the menu of damages to coastal water: overfishing, oil spills, and pollution, to name a few. What can be lost in the discussion of these issues is how they reverberate far beneath.

      Maybe the greatest alarm in recent years has followed the discovery of plastic floating in the ocean. Scientists estimate that 17 billion pounds of polymer are flushed into the ocean each year, and substantially more of it collects on the bottom than on the surface. Just as a bottle that falls from a picnic table will roll downhill to a gulch, trash on the seafloor gradually makes its way toward deepwater plains and hadal trenches. After his expedition to the trenches, Victor Vescovo returned with the news that garbage had beaten him there. He found a plastic bag at the bottom of one trench, a beverage can in another, and when he reached the deepest point in the Mariana, he watched an object with a large S on the side float past his window. Trash of all sorts is collecting in the hadal—Spam tins, Budweiser cans, rubber gloves, even a mannequin head.

      Scientists are just beginning to understand the impact of trash on aquatic life.

      https://marinedebris.noaa.gov/info/patch.html

      Microbes that flourish on plastic have ballooned in number, replacing other species as their population explodes in a polymer ocean.

      If it seems trivial to worry about the population statistics of bacteria in the ocean, you may be interested to know that ocean microbes are essential to human and planetary health. About a third of the carbon dioxide generated on land is absorbed by underwater organisms, including one species that was just discovered in the CCZ in 2018. The researchers who found that bacterium have no idea how it removes carbon from the environment, but their findings show that it may account for up to 10 percent of the volume that is sequestered by oceans every year.

      “There are more than a million microbes per milliliter of seawater,” he said, “so the chance of finding new antibiotics in the marine environment is high.” McCarthy agreed. “The next great drug may be hidden somewhere deep in the water,” he said. “We need to get to the deep-sea organisms, because they’re making compounds that we’ve never seen before. We may find drugs that could be used to treat gout, or rheumatoid arthritis, or all kinds of other conditions.”

      Marine biologists have never conducted a comprehensive survey of microbes in the hadal trenches. The conventional tools of water sampling cannot function at extreme depth, and engineers are just beginning to develop tools that can. Microbial studies of the deepwater plains are slightly further along—and scientists have recently discovered that the CCZ is unusually flush with life.

      Venter has been accused of trying to privatize the human genome, and many of his critics believe his effort to create new organisms is akin to playing God. He clearly doesn’t have an aversion to profit-driven science, and he’s not afraid to mess with nature—yet when I asked him about the prospect of mining in deep water, he flared with alarm. “We should be very careful about mining in the ocean,” he said. “These companies should be doing rigorous microbial surveys before they do anything else. We only know a fraction of the microbes down there, and it’s a terrible idea to screw with them before we know what they are and what they do.”

      As a group, they have sought to position DeepGreen as a company whose primary interest in mining the ocean is saving the planet. They have produced a series of lavish brochures to explain the need for a new source of battery metals, and Gerard Barron, the CEO, speaks with animated fervor about the virtues of nodule extraction.

      His case for seabed mining is straightforward. Barron believes that the world will not survive if we continue burning fossil fuels, and the transition to other forms of power will require a massive increase in battery production. He points to electric cars: the batteries for a single vehicle require 187 pounds of copper, 123 pounds of nickel, and 15 pounds each of manganese and cobalt. On a planet with 1 billion cars, the conversion to electric vehicles would require several times more metal than all existing land-based supplies—and harvesting that metal from existing sources already takes a human toll.

      L’enfer sur Terre, que cette histoire de seabed mining puisse être considérée comme écolo, de même qu’un milliard de bagnoles « vertes » !

      Mining companies may promise to extract seabed metal with minimal damage to the surrounding environment, but to believe this requires faith. It collides with the force of human history, the law of unintended consequences, and the inevitability of mistakes. I wanted to understand from Michael Lodge how a UN agency had made the choice to accept that risk.

      “Why is it necessary to mine the ocean?” I asked him.

      He paused for a moment, furrowing his brow. “I don’t know why you use the word necessary,” he said. “Why is it ‘necessary’ to mine anywhere? You mine where you find metal.”

      #extractivisme #extractivisme_marin #mer #océan #eau #mine #capitalisme_vert #tourisme_de_l'extrême par nos amis les #milliardaires #biologie_de_synthèse aussi #microbes #antibiotiques et un gros #beurk