We know that the world has a total of six continents, namely: Eurasia, Africa, North America, South America, Australia and Antarctica. But it is said that the "seventh continent" is now forming on the earth, what is the "seventh continent", where is it, how it is formed, this issue of Xiaobian will take you to decrypt.
1. What is the "Seventh Continent"
Source: Standard map service system
The "Seventh Continent" is actually the garbage continent, and the total amount of garbage in this "New World" is estimated to exceed 7 million tons, and there are 3.3 million large and small pieces of plastic per square kilometer of sea. In the most serious places, the thickness of garbage piled up on the seabed has reached 30 meters.
2. The discovery of the "garbage continent"
In 1997, an American captain named Charles Moore sailed through it in order to cut a short path, and then he was surprised to find that his ship had actually sailed into a huge "garbage dump". Captain Moore said, "All I can see is rubbish. Bottle caps, bags, inflatable volleyballs... More plastic fragments, which float around the ship... I couldn't find a single clean place at all. ”
It took Captain Moore a week to "break out" from this huge "garbage dump." After returning to the United States, he used samples brought back from the "garbage dump" to detect that the amount of plastic waste particles in some parts of the area was 6 times that of marine plankton. He initially estimated that at least 3 million tons of plastic waste were floating in the sea. Then he told the media in frustration: "Even if the country's financial resources are exhausted, it may not be able to clean up the plastic waste here." ”
3. Who created the "garbage continent"?
So much oceanic garbage comes from the human world thousands of kilometers away.
According to the United Nations, the world produces more than 260 million tons of plastic waste every year, most of which is disposable, of which 90% to 95% is not recycled, most of which is discarded by humans at will - some are buried in the land, some are scattered in the suburbs of the garbage dump, some hang on the branches of the treetops along the railway, some are dumped directly into the sea... They are scattered in every corner of the earth, but in the end they will be washed by rain or high winds, and then quietly flow away: "The final destination is the ocean." ”
This "garbage continent" is still growing and does not form a solid land. But its growth rate has been staggering, doubling its size in just the past decade to spread to 1.4 million square kilometers of land and amass more than 7 million tons of garbage.
4. Where is this "Seventh Continent"?
The "Seventh Continent," also known as the "Pacific Garbage Vortex," is located between latitudes 35° and 42° north, northeast of the Hawaiian Islands, 1,000 miles off the coast of California, and belongs to the "windless zone."
The so-called "windless zone", its formation is related to the uneven heating of the earth: near the equator, direct sunlight, ground air heat expansion, lighter rise. After rising to about 8,000 meters, it flows in the direction of the north and south poles. This north-south movement of the atmosphere, under the influence of the Earth's rotational deflection force, gradually changes direction: northward to northeast, southward to southeast. This bias increases with the increase of latitude, and over the latitude of 30° to 35° north and south, it almost becomes a westerly wind and no longer advances. The air near the equator is continuously replenished, so a large amount of air is crowded above the north and south latitudes of 30 ° to 35 °, so that the ground pressure rises, forming a subtropical high-pressure zone in the northern and southern hemispheres. There is little cloud and less rain here, and there is very little wind. Ancient navigators used to name it "Horse Latitude", because when their sailboats sailed to this area, they had to spend a long time waiting for the arrival of the downwind, so that the horses on board died of lack of hay and had to run into the sea. For this reason, ocean-going boats generally do not pass through here, and even fishermen rarely come here, because there are very few fish here.
But why is so much garbage gathering in this inaccessible sea? This also starts with the currents in secondary school geography.
According to the above figure, it is not difficult to see that there is a circulation in the middle of the Pacific Ocean, which is a clockwise circular system composed of the North Equatorial Warm Current, the Japan Warm Current, the North Pacific Warm Current, and the California Cold Current. Based on the direction of this circulation, we can reconstruct how this floating plastic waste came to be here:
Map Source: Map of the Earth >> World Map >> World >> World Geography >> The formation of world currents and planetary wind systems and wind currents
For example, it may be a toothbrush that has been abandoned on the west coast of the United States, at first, it will follow the California cold current all the way south, to the Mexican area, and then through the North Equatorial Warm Current to Flow to Asia, all the way to the Japanese Sea, and then it will encounter the Japanese Warm Current, turn east, join the North Pacific Warm Current, pass through Hawaii, and finally reach the "Garbage Continent", the whole journey will take several years.
Of course, if it were discarded along the coast of Asia, the journey would be greatly shortened, with only one year to reach the New World. Scientists predict that 50 percent of the plastic waste in this area comes from Asia, and the "garbage continent" has a tendency to spread to the Coast of Asia, which is very worrying.
What is even more worrying is that this "garbage continent" is not the only one in the ocean.
Map Source: Map of the Earth >> World Map >> World >> World Currents and Climate Map
There are a total of 5 similar current vortexes on Earth, and theoretically, they all have marine debris accumulation: "For example, we know that the current vortex in the southern hemisphere has a stronger flow rate, so the garbage will be more concentrated." We don't yet know exactly how much garbage there is, but given the greater concentration of people in North America and Asia, there may be less garbage in the South Pacific than in the North Pacific. But in any case, plastic waste will not disappear once it is generated.
5. The harm of the "garbage continent"
Plastic waste in the light, wind and ocean currents of the combined action, split into countless tiny plastic particles, these particles in the sea water continue to adsorb heavy metals and a variety of toxic substances, fish may be these plastic particles by mistake, toxic substances in the fish body, and then along the food chain to seabirds and other marine animals, resulting in a large area of death of marine life... Don't think this has nothing to do with humans, because eventually all the toxins will be passed on to the top of the food chain, the human table. This bowl of "plastic soup" from human hands may eventually be drunk into our stomachs in some way.
China's 34th Antarctic scientific expedition scientists have found traces of microplastics in the seawater of antarctic waters for the first time, and these plastic fragments of less than 5 mm in size can be found in such an inaccessible way, which has aroused the concern of scientists.
For more information, watch the documentary "Plastic Ocean".
6, the method: turn garbage into fuel?
Scientists intend to use two methods: one is to use a special fishing net, which can catch a relatively large plastic waste, the damage to marine life is minimized; the other is the "beach method": a flat shape device is put into the sea, using the action of tides and winds, you can salvage small plastic waste.
However, the likelihood that this weathered plastic waste will be recycled is also very small. Of all the plastic waste, the easiest to recycle and reuse is PETE plastic (polyethylene terephthalate). They can be recycled into synthetic cotton wool and tucked into winter coats, camping bags and life jackets. Unfortunately, PETE plastic is not found in the "Seventh Continent". This is because after the plastic bottle enters the ocean, it will sink directly to the bottom of the sea.
Scientists have come up with another idea — to turn them into fuel. The technology to convert plastics into energy on land is quite mature, and the waste of the "Seventh Continent" is far away in the center of the ocean, and the cost of salvaging and transporting it to land is very high. Therefore, it was suggested that this garbage could be disposed of in situ in the ocean center and converted into fuel for the navigation of ships.
The best way to get rid of this waste is to minimize the use of plastic products. When using plastic products, you can ask yourself: Do I really need it? Every year, more than half of so many plastic products are discarded after using them once, and some of them stay in our hands for only a few tens of seconds. So the editor finally appealed:
Minimize the use of plastic products
Start with me
Start now!