This article is selected from the journal of the Chinese Academy of Engineering, Engineering, Issue 10, 2022
Written by Sean O ́Neill
来源：Satellite Tracking and Global Treaty Effort Open New Front on Plastic Waste Problem[J]. Engineering,2022,17(10):3-6.
Editor's note
In May 2022, the Global Plastics Watch (GPW) satellite platform to monitor plastic pollution on land around the world became operational. GPW is a tool that combines Earth observation and artificial intelligence to create real-time, high-resolution maps of plastic pollution from space, resulting in datasets that can help regulators more effectively prevent plastic leakage into the marine environment.
The 10th issue of Engineering, a journal of the Chinese Academy of Engineering, published an article entitled "Satellite tracking and global treaties open up new ways to solve the problem of plastic waste", introducing the overview of global plastic pollution and the current positive actions to solve this problem. The article pointed out that global plastic governance needs to start from plastic production, plastic pollution and other aspects, use advanced technologies such as satellite technology, and formulate global treaties to regulate and restrict plastic pollution and the entire life cycle of plastics.
As the rate of plastic production continues to rise, plastic production is expected to reach 1 × 109 tons per year by 2050 (Figure 1), and the amount of plastic waste will also increase. A new satellite platform, Global Plastics Watch (GPW), launched in May 2022, has begun monitoring plastic pollution on land worldwide. GPW is a freely accessible online platform that combines spectral data from the European Space Agency's Sentinel-2 satellite with machine learning to identify and monitor plastic waste around the world. This is another example of the use of increasingly advanced satellite technology to address climate change and other long-term environmental problems.
The platform, which assists governments, industry and communities in preventing plastic leakage into aquatic ecosystems, which can cause particular damage, is currently funded by the Minderoo Foundation, a charity based in Perth, Australia. The GPW shows not only the current size of plastic-rich dumps (resolution 5 m × 5 m), but also information such as how they have changed over time, their distance from watercourses, soil and topographic characteristics, and local population density (Figure 2).
Figure 1. (a) In 2017, total plastic production was approximately 8.3 × 109 t. (b) Annual production is expected to exceed 1 billion tonnes by 2050. Source: United Nations Environment Programme (UNEP) and GRID-Arendal Centre, cited with permission.
Figure 2. The GPW platform provides insight into plastic dumps in 25 countries, where most plastic waste ends up in aquatic ecosystems. These sample GPW screenshots show the following information: (a) the physical extent of a single dumpsite at different points in time in a province of Indonesia, overlaid on a Google Earth-style map; and (b) a Google Street View image of one of the dumps identified in the previous screenshot. Source: Global Plastics Watch, cited with permission.
Fabian Laurier, Head of Technology Innovation and Marine Conservation at the Middleloo Foundation, said: "GPW focuses on the entire process of plastic from being discarded by users to ending up in formal, unlicensed or illegal dumps. Plastic flowing into the ocean is like milk falling into tea, and it is almost impossible to recycle. We must first prevent plastic from entering the river system. ”
Laurent Lebreton, head of research at The Ocean Cleanup, an international organization based in Rotterdam, Netherlands, which develops technologies to remove and intercept plastic pollution on the ocean surface and in rivers, said that while a lot of plastic is dumped directly into the ocean, more plastic waste comes from land. "The current consensus is that about 20 percent of this garbage comes from the ocean and 80 percent from land. But in fact, we don't know for sure. Moreover, most of the floating garbage discharged from rivers into the ocean is quickly carried back ashore by the waves. (Figure 3)
Figure 3. Much of the floating trash that enters the ocean from rivers is a major source of marine plastic litter, but it is quickly brought back to the beach, like this one in Honduras. Source: Jingyang Defender, with permission to quote.
The GPW platform currently covers 25 countries identified in a 2021 paper in the journal Science Advances as the countries with the highest rates of plastic pollution being discharged into rivers and eventually entering the ocean. Lebreton, the paper's senior author, provides an example that proves that GPW is useful. He was working on a garbage interception project in Rio de Las Vacas, a tributary of the Rio Motagua River in Guatemala (Figure 4). Lebreton said: "I've never seen so much plastic in a river before. We found that upstream of Guatemala City, above the river, a huge and unreasonably controlled open landfill suddenly appeared on the GPW platform. "This additional document on the cause of the problem facilitated discussions with the country's managers. "Just documenting this in file form is a testament to the power of this platform," Lebreton said. It allows us to focus our attention on the upper reaches of the river and will have a significant impact on policymaking. ”
Figure 4. Plastic waste temporarily captured by an experimental "garbage fence" built by Clean Ocean Defenders on Rio de Las Vacas in Guatemala. During the pilot work in May 2022, a large amount of garbage eventually led to the failure of this barrier. Source: Jingyang Defender, with permission to quote.
While GPW plans to cover the rest of the world, European countries and the United States are currently not among the 25 countries monitored by the platform. "We know that developed countries export waste to poorer countries, and we want to know how this waste affects marine litter," Laurier said. But this is not a tool to blame each other. ”
Steph Borrelle, an environmental researcher at the University of Toronto in Canada and the Pacific regional coordinator for BirdLife International in New Zealand, said that while the GPW did not solve the problem of Western countries exporting plastic waste to developing countries, the additional oversight of plastic waste was welcome. Borrelle, lead author of a 2020 paper in the journal Science, which modeled how the projected growth of plastic waste would far outpace the treatment of plastic pollution, said: "The amount of plastic entering the world's aquatic ecosystems each year is staggering. I kept thinking, 'This must be a mistake' when I analyzed it, but after repeated data checks, the opposite was true. According to Borrelle and his co-authors, in 2016, 1.9 × 107~2.3 × 107 tons of domestic plastic waste entered the aquatic ecosystem, equivalent to about 11% of all plastic waste generated globally that year. According to the research team's "business as usual" scenario, the annual domestic plastic waste entering the ocean could rise to 9× 107 tons by 2030.
When plastic enters rivers and oceans, wave action, sunlight and wind cause them to gradually break down into microplastic particles less than 5 mm in length, harming and killing a range of aquatic life. Microplastics can now be found almost everywhere in the ocean, on land, in the polar regions and even on mountain tops. Borrelle said: "Now that microplastics are found in the human body, in the placenta of the unborn baby, in most animals, and even in the air, we actually live in a 'Plastisphere'. ”
Of the 8.3 × 109 t of plastic produced since the 50s of the 20th century, an estimated 5.7 × 109 t of the plastic produced has become waste, of which only about 9% is recycled and the rest is disposed of in landfills or incinerators (Figure 1). According to Borrelle, while recycling efforts are laudable, it's not the answer to the problem of plastic pollution. "Plastic is not infinitely recyclable. It can only 'downgrade recycling'. So, no matter how it is recycled, it will eventually become waste. ”
Plastic recycling also faces the problem of economy. For example, in Europe, the cost of the most common type of recycled plastic (post-consumer polyethylene terephthalate) doubled during 2021, becoming more expensive than its virgin plastic equivalent.
Still, in the bleak global context of plastic pollution, there are reasons for optimism. At the Fifth United Nations Environment Assembly (UNEA-5) in Nairobi, Kenya, on March 2, 2022, world leaders unanimously adopted a historic resolution to tackle plastic pollution globally, and the United Nations Environment Programme (UNEP) also called the day "a historic day in the fight against plastic pollution." The resolution Ending Plastic Pollution: Developing an International Legally Binding Instrument launched negotiations on a global treaty; The treaty aims to address not only plastic pollution in all environments, but also the entire life cycle of plastics, including primary (unprocessed) production, product design and waste management. The resolution also establishes an intergovernmental negotiating committee with the goal of finalizing the drafting of the legally binding global agreement by the end of 2024.
The Environmental Investigation Agency (EIA), a London-based NGO, garnered support for the adoption of the resolution ahead of the meeting, for example on the eve of the Nairobi negotiations, which resulted in a Scientist Declaration. Christina Dixon, head of the agency's Ocean Campaign, said: "In environmental campaigns and advocacy, it is very difficult and extremely rare to win. But UNEA-5's collective spirit and common purpose are very strong. ”
The resolution involves the development of national reporting standards for plastic production and includes the creation of a dedicated fund to support poorer countries in implementing the treaty. Crucially, the resolution also provides room for negotiation to force reductions in the production of virgin plastics. Tom Gammage, EIA marine campaigner who coordinates the Scientists' Declaration, said: "Tackling plastic pollution means tackling plastic production, and the two are inseparable. ”
At the same time, people are increasingly aware of the importance of plastic pollution control and have taken action. For example, many countries have made independent progress in tackling plastic pollution by banning certain forms of single-use plastics. In July 2022, California, USA, passed a new law to restrict the use of plastic, while requiring manufacturers to promote recycling and take other actions.
But Gammage also said these efforts alone won't solve the problem. He expects the United Nations (UN) treaty to eventually provide for new regulations for global coordination and national implementation of the types and quantities of plastic production, the manufacture of plastic products, and new regulations on plastics in different industries, from fishing and agriculture to plastic packaging and textiles.
The main producer of virgin plastics is the petrochemical industry. According to the Plastic Waste Producer Index report published by the Mindelo Foundation, just 20 polymer producers produce more than half of the world's single-use plastics, which end up as waste. ExxonMobil and Dow headquartered in the United States and Sinopec, headquartered in China, are at the top of the list (Figure 5).
Figure 5. Top 20 polymer producers producing single-use plastics. PTT: Petroleum Authority of Thailand. Source: Minderoo Foundation, cited with permission.
Environmentalists expect the petrochemical industry to lobby hard economically to weaken future treaty controls on plastic production. "By doing this type of activity, these companies are refusing to acknowledge the impact of their products on human health or the environment and shifting the blame to their customers," Borrelle said. ”
Dixon is also worried about this. "The oil and gas business model relies on no control over plastic production," he said. What they want is unlimited mass production. At the Nairobi meeting, the industry lobby remained somewhat behind the scenes. But we expect more activity from this strong group of supporters during treaty negotiations. ”
At the same time, the GPW will be put to good use, Laurier said: "We are working closely with the United Nations Environment Programme to explore how this tool can be used to inform the development of treaties and to gain a clearer picture of global waste and waste management trends, or gaps in waste management." ”
Note: The content of this article has been slightly adjusted, if necessary, you can view the original text.
Adapted from the original text:
Sean O´Neill.Satellite Tracking and Global Treaty Effort Open New Front on Plastic Waste Problem [J]. Engineering,2022,17(10):3-6.
Note: The paper reflects the progress of research results and does not represent the views of China Engineering Science magazine.