Air, water, and land

Lane Kenworthy, The Good Society
February 2024

We want clean and abundant air, water, and land. How do we get them and sustain them?

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AIR

Clean air

Air pollution is one of the world’s biggest killers, though it’s seldom listed as an official cause of death. International health agencies estimate that pollutants in the air cause about 7 million deaths each year, which is more than 10% of all deaths worldwide.1

Air pollution comes from burning things — mainly wood, crops (biomass), coal, and oil. The small particles produced by this burning can get deep into people’s lungs, contributing to respiratory disease, stroke, cardiovascular disease, and lung cancer.2

We’ve been making progress. We tend to think of modern cities such as Delhi and Shanghai as having horrible air pollution, yet air quality levels today are considerably better in all of the world’s major cities than they were in 19th-century London.3 And since 1990 the death rate from air pollution has dropped by approximately half.4

The cause of this progress has been a shift in what we burn — away from the most deadly sources of air pollution toward sources that are less harmful. Hannah Ritchie notes that “Globally our emissions come from a handful of sources. The first is burning wood or charcoal for energy or burning crops in the field. This is one of the biggest sources at lower incomes, and a big contributor to indoor and outdoor pollution. Then we have emissions from agriculture, with the ammonia and nitrogen gases that come from manure and fertilizers. The next is burning fossil fuels for electricity. Then emissions from industry – the fumes leaking out of chemical plants, metal manufacturers and textile factories. Finally, we have transport – the cars we drive, but also the trucks, ships and planes that carry goods around the world.”5 Burning wood creates more harmful air particles than burning coal, which in turn is worse than gas. As more and more of the world’s population has moved up the “energy ladder,” shifting from energy sources that create more air pollution to those that create less, pollution has decreased.

But the level of air pollutants remains far too high. About 40% of the world’s population still relies on burning wood, charcoal, or coal as the main source of energy for their household. Farmers in many places must burn crop residue in order to manage the short turnaround from harvesting to planting. Operators of coal power plants in many nations don’t feel they can afford to install a “scrubber” that captures the sulphur dioxide produced by the plant. And many people around the world don’t have the option or the financial capability to replace their fossil-fuel-burning car with one powered by clean energy.

What’s the solution? We need higher incomes for families, which will allow them to choose less-polluting energy sources. We need subsidies for farmers to encourage them to burn less biomass. We need regulations and subsidies to get scrubbers installed in more coal power plants. And we need continued innovation and subsidization to push forward the shift to clean energy. We also would benefit from urban design (or redesign) that encourages use of public transportation, bikes, and walking.6

Is the earth running out of oxygen?

One alarm making the rounds on social media and elsewhere recently is that our planet might soon run out of oxygen. The claim is that the Amazon provides 20% of Earth’s oxygen, so continued deforestation of the Amazon will cause “a reduction in the planet’s ‘lung capacity’.”7

That’s not correct: “None of the world’s forests or vegetation give much to our oxygen supply. As the geologist Shanan Peters calculated: ‘if every living thing other than humans burned up, oxygen levels would fall from 20.9% to 20.4%’. It would also take millions of years to deplete the globe’s oxygen supply by any notable amount.”8 We should be concerned about deforestation (see below), but not because it will reduce our oxygen supply.

WATER

Water for drinking and other household uses

We want abundant clean water to drink and to use for other purposes. Historically, our main water sources have been rivers, standing pools of water (lakes, reservoirs), and underground water (in aquifers or soil). But as urbanization advances and as weather patterns shift, some of these will become less reliable. To ensure a sufficient supply of water, we’ll need to make more efficient use of it.

We know how to do this. A big part of the solution to water supply is shifting agricultural production away from meat and dairy products — something we’ll want to do for other reasons as well (see below). Worldwide, farming accounts for about 70% of our water use.9

There is more. Technology now exists to capture rainwater runoff more effectively, to desalinate ocean water, and to recycle wastewater. Cities such as San Diego and Irvine in California, Altamonte in Florida, and Tel Aviv in Israel have led the way in adding these strategies to assure an ample water supply going forward.10 Drawing upon a variety of water sources, rather than just one or two, also enhances the resilience of a city’s water system.

Limiting the incidence and duration of malfunctions also can help. In some places a significant portion of the water supply is lost due to leaks in pipes — around 10% in the United States, 30% in London, 50% in Sao Paolo and Rio de Janeiro.11 Better detection technology will help to identify water leaks.12

What about ensuring that our water is clean? Here the key is government services and regulations. Following the discovery more than a century ago that water was a key source of cholera and typhoid, governments began to require that water be chlorinated and filtered, which dramatically reduced the spread of these diseases. Keys to ensuring clean water today include regulation of wastewater treatment and of the infrastructure through which water is delivered to residential and commercial buildings, schools, parks, and other sites. Governments also monitor the quality of the water itself.

Rivers and lakes

By the 1960s, water quality in rivers, streams, and lakes (“surface water”) in countries like the United States had become heavily degraded — by waste runoff from factories, by fertilizers and pesticides from farms, and by other pollutants.

But then people demanded change, and governments responded. The US federal government created the Environmental Protection Agency in 1970 and enacted the Clean Water Act in 1970. This resulted in laws that impose penalties for businesses that discharge particular types or quantities of pollutants into lakes, rivers, or groundwater and that regulate wastewater treatment facilities and processes. Half a century later, surface water quality across the United States has improved significantly.13

Oceans

Between 1950 and 2019 we produced approximately 10 billion tons of plastic. Because plastic is quite durable, most of it is still around in some form. It’s estimated that about 1 million tons enters the oceans each year — 0.3% of total plastic waste.14 This is harming sea animals and could potentially alter ocean currents and protective reefs. (It’s often thought to be harming people too, when we ingest small particles, but so far the evidence suggests this isn’t a significant concern.15)

Should we ban plastic? No, at least not at this stage. It serves numerous useful purposes, including in medical supplies, food protection, housing, and more.

Should we recycle more of it? Yes, but that will only get us so far. Plastic degrades when used, so when it’s recycled it’s used in a lower-quality form. Most plastics can’t be recycled more than once or twice.16

A solution to plastics in the ocean has four main parts. First, reduce the prevalence of single-use plastic items. San Francisco enacted a ban on single-use plastic bags in 2010, and within a decade this led to a 75% reduction in plastic litter on local beaches.17 Other cities, states, and countries are beginning to follow suit. In 2018, the European Union enacted a strategy to make half of plastic packaging recyclable by 2025 and all of it by 2030. In 2021 it banned the ten most common single-use plastic items.

The second is simple waste management. Nearly all of the plastics that end up in the ocean come from less affluent countries that lack comprehensive systems of waste collection and disposal. As Hannah Ritchie notes, “The biggest solution to ending plastic pollution is not a glamorous one…. It’s the grimy but necessary investment in waste management. If every country had the waste-management systems that rich countries have, almost no plastic would end up in the ocean. Countries need landfills that actually seal on top, so rubbish doesn’t escape. They need good systems for collecting and storing the rubbish from thousands of streets across megacities…. Low- to middle-income countries can accelerate this transition by investing in waste management now. Rich countries can support them by financing this effort.”18

The third part is preventing plastics that get dumped from floating into the ocean. There are a variety of inventions already being tried in this area, some of which surely will prove both effective and efficient.19

Finally, we can try to remove plastic that’s already in the ocean. Innovative scrapers are being tested and deployed to do just that.20

Flooding

Climate change will increase the number of floods cities face, whether from more intense rainstorms or from rising sea levels. This has implications for wastewater systems.

Following a thousand-year storm in 2011, Copenhagen developed a plan to manage the stormwater from large rainstorms more effectively. The planning team calculated that rather than expand the existing sewer system, it would be more effective and efficient to create a new surface infrastructure to manage storm water in the city. The new system works in parallel with the existing system, keeping storm water out of the sewer system by capturing it, storing it, and directing it to plants and green spaces. This is achieved with roof gardens, rain barrels, rain gardens, permeable walk paths, cloudburst roads, and other mechanisms. The system thereby minimizes flooding and at the same time makes use of stormwater to enhance the beauty of the city.21 The combined system can be adjusted in the face of new developments, and this flexibility enhances resilience. Cities in Sweden, the United States, and China have begun to emulate and improve on this approach.22

LAND

Land use, climate change, and biodiversity loss

The way we currently use land has two problematic consequences. First, it contributes to climate change. When we cut down or burn trees or other biomass — for food production or fuel or housing or some other purpose — it releases greenhouse gases into the atmosphere. This makes it more difficult for us to hold global warming in check.23

Second, we are harming or killing off species — that is, we are reducing biodiversity. There are somewhere between 5 and 10 million species on Earth. Since 1500, according to the best available estimates, around 1% of the planet’s species have gone extinct (1.4% of mammals, 1.3% of birds, 0.6% of amphibians, 0.2% of reptiles, and 0.2% of bony fishes).24 That doesn’t sound like a lot, but this rate of extinction is much more rapid than the “natural” rate. Typically, around 10% of species disappear every million years, 30% every 10 million years, and 65% every 100 million years.25 At the rate of extinction that we’ve witnessed since 1500, about 75% of all species would be lost in 37,500 years.

Why do we care about species and biodiversity? Part of it is joy and fascination. Some people love animals, either in general or of particular types, and will be saddened if those animals disappear. More important, biodiversity contributes to the balance on which our ecosystems depend. How exactly does this work? And how critical are specific species to this balance? In most instances, we don’t know. Ecosystems are a complex mix of needs and dependencies between species. We understand relatively little about how they work.26 Given this ignorance, the wise path is to err on the side of protecting biodiversity.

It’s worth emphasizing that the loss of one or more species, however saddening, is neither unusual nor problematic from the point of view of sustaining life on earth. As noted earlier, loss of particular species has been a regular occurrence, and that will continue to be the case. Approximately 99% of the 4 billion species that have ever existed on Earth have gone extinct.27

Nevertheless, with the current rate of species extinction we are taking a bigger risk than we ought to.

To minimize climate change and biodiversity loss, our most important step is to shift food production away from beef and other meats. Most of the land that we develop — that we directly alter — goes to meat production.28 And the single biggest driver of deforestation is forest clearance for production of beef.29

Meat products use a lot of land not only because there is a large demand for these foods but also because they are a very inefficient type of food. They require a comparatively large amount of land per calorie or per ounce of protein. For every 100 calories of food we provide to cows, we get only 3 calories back in beef. And beef requires about 100 times more land than beans or tofu to generate the same amount of protein. Lamb, pigs, and chickens are nearly as bad.30 Switching from meat to plant-based foods would sharply reduce the quantity of land we need for food production.

The problem with our meat-centered food system is broader than this. Here’s how Hannah Ritchie puts it31:

Look at any of the world’s environmental problems and food lies close to the centre. It really is at the nexus of sustainability…. The food system is responsible for one-quarter of the world’s greenhouse gas emissions. But even if we were to take climate change out of the picture, we would need to fix our food system to tackle our other environmental problems.

Worried about pressures on freshwater supplies? Agriculture is responsible for around 70% of global freshwater withdrawals. In some tropical countries, more than 90% is used for farming. Worried about deforestation? Take agriculture out of the picture and the problem almost disappears. Worried about biodiversity loss? Again, food production is the biggest pressure on the world’s wildlife. It always has been. From overhunting animals for food and claiming their habitats for farmland, to killing off ecosystems with pesticides and fertilisers, the largest threat to the world’s animals is human demand for food. Worried about water pollution? You guessed it: farming comes out on top. When we put nutrients in our soils and crops, most of them run off the land and into rivers, lakes, and the ocean. These nutrients throw ecosystems into havoc: species such as algae take advantage and bloom everywhere. Fish and other animals are starved of oxygen, and our waters turn into zones dead of life.

Zoom out and we can see the scale of the impact that farming has had on reshaping our planet. Today, half of the world’s ice- and desert-free land is used for agriculture. Much more land is used for farming than the world has in the form of forests. Three-quarters of this is used for raising livestock — either land for grazing or for growing crops to feed it. What’s staggering is how imbalanced this is when it comes to the food we finally eat. Meat and dairy give us just 18% of our calories, and 37% of our protein. We put a lot of resources into livestock, but the returns are not great.

We should try to use less land. We already produce enough food for every human to have about 5,000 calories per day, which is double what we need.32 But too much of this goes to feed animals, which require lots of land. Currently we use 50% of the planet’s habitable land area for farming. If we can increase the productivity of farming everywhere to the levels that obtain in rich nations and if we shift toward a plant-based diet, we could reduce that to as little as 4% to 8%, according to one informed calculation.33

Should we stop using fertilizers, pesticides, and genetically modified seeds? No. These are key to efficient food production. They enable us to produce enough to feed everyone. And they enable us to do it while using a reasonably modest amount of land. Banning them would yield little in health benefits34 and likely would increase hunger and starvation. Or we might end up compensating for the resulting reduction in farming efficiency by using more land, which would be bad for climate change and for biodiversity, for the reasons noted earlier.

Instead, we should continue trying to create better seed varieties and less harmful fertilizers and pesticides. We should try to use them on land that will release the smallest amount of greenhouse gases and will do the least damage to biodiversity. And we should continue to try to invent alternative ways to produce food, whether in labs or factories or something else.

Another valuable step is to give some land “protected” status. This varies from areas where “sustainable” use of natural resources (logging, fishing) is permitted to strict nature preserves. Currently, about 16% of the planet’s land is in a protected area, and that is scheduled to increase to 30% by 2030.35

Finally, rich countries can pay poor countries to save land from agricultural use or from forest clearing.36

Is solid waste disposal a problem?

Are we rapidly using up land space by burying our trash in it? Some Americans, looking at how full their trash cans get and vaguely recalling that New York City once was forced to store its trash on a floating barge, assume that we’re running out of landfill space. And they worry that everything they put in the recycling bin ends up in a landfill because China no longer accepts recycled material. Moreover, transporting trash to landfills increases greenhouse gas emissions, as does methane leaking from those landfills. Solid waste management accounts for about 5% of greenhouse gas emissions.37

The reality is far less dire. There is no shortage of landfill space. Even if we were to put all of America’s solid waste in landfills for the next 1,000 years, that would take up only 0.1% of the country’s land mass.38 And due to regulations enacted between the mid-1960s and the mid-1980s, the solid waste that is buried today goes into sanitary landfills rather than open dumps.39 Not only is this safe and clean, but the land is potentially reusable. Ellis Island in New York City, much of modern Boston, and about one-fifth of Singapore are built on top of buried solid waste.40

More important, while Americans now generate about twice as much solid waste as we did half a century ago, we’ve dramatically expanded the share that we recycle or incinerate, so the amount of waste that’s placed into landfills each year has remained constant since 1980.41 Other nations have done even better. In high-income countries about 35% of solid waste goes to recycling and composting, about 25% to incinerating, and 40% to landfills.42 With improved technologies, policies, and norms, we will do better still. In Japan and Sweden, only 1% goes to landfills.43

Lower-income countries currently don’t do nearly as well.44 On average, about 60% of solid waste in such countries isn’t collected. Largely for this reason, more than 90% of waste in poor nations is burned or disposed in open-air dumps, compared to just 2% in high-income countries. This can be bad for health and safety. “When waste is burned, the resulting toxins and particulate matter in the air can cause respiratory and neurological diseases, among others. Piles of waste produce toxic liquid runoff called leachate, which can drain into rivers, groundwater, and soil. Organic waste entering waterways reduces the amount of oxygen available and promotes the growth of harmful organisms.”45

Urbanization helps. Poorer nations are less urbanized, and waste collection is much more common in cities than in rural areas. Indeed, a larger share of solid waste gets collected in cities in low-income countries than in rural areas in upper-middle-income countries.46 So continued urbanization will be beneficial.

The other key is money. In low-income nations, solid waste collection consumes about 20% of municipal budgets, compared to just 4% in high-income nations. As countries get richer they will do better with solid waste management, but they also will generate a larger quantity of it,47 so reducing the cost or figuring out other ways to hasten their adoption of optimal collection, recycling, composting, incineration, and landfill procedures will be good for their citizens and good for the planet. One option is for the national government to partly finance local solid waste management until collection, transportation, and disposal systems become more efficient or household incomes rise enough to afford higher user fees. Some countries, such as Colombia and Senegal, have successfully used this approach.48

Soft pressure from peer comparison may also help. This has been one of the contributors to Japan’s success. “Each year, the national Ministry of the Environment conducts an annual waste management survey. Local governments’ responses are aggregated in a comprehensive database that both national and local governments use to develop plans, strategies, and policies. Information surveyed includes the quantity of waste that is generated and the amount of waste disposed of via recycling, composting, and incineration. The materials recovery rates reported through the survey are disclosed to the public, which provides incentives to local governments to increase sustainable disposal practices. The transparent data system allows local governments to compare their plans and outcomes with those of other local governments that have similar economic and demographic profiles. Local governments use this information to evaluate and continually improve their processes. Members of the public and academic organizations may also use the data to evaluate the effectiveness of the waste management system.”49

SUMMARY

We face significant challenges in securing abundant clean air, water, and land. However, we’re already in better shape than many pessimists believe, we’ve already made some progress, and we know what to do in order to solve these problems.

  1. Hannah Ritchie, Not the End of the World: How We Can Be the First Generation to Build a Sustainable Planet, Little, Brown Spark, 2024, ch. 2. ↩︎
  2. Ritchie, Not the End of the World, ch. 2. ↩︎
  3. Ritchie, Not the End of the World, ch. 2. ↩︎
  4. C.J.L. Murray et al., “Global Burden of 87 Risk Factors in 204 Countries and Territories, 1990–2019: A Systematic Analysis for the Global Burden of Disease Study 2019,” Lancet, 2020. ↩︎
  5. Ritchie, Not the End of the World, pp. 54-55 ↩︎
  6. Ritchie, Not the End of the World, ch. 2. ↩︎
  7. New York Times, cited in Ritchie, Not the End of the World, ch. 4. ↩︎
  8. Ritchie, Not the End of the World, p. 116. ↩︎
  9. Hannah Ritchie and Max Roser, “Water Use and Stress,” Our World in Data. ↩︎
  10. John Addison, “An Overview of California’s Water Challenges and Solutions,” Meeting of the Minds, 2018; Frank Martz, Ed Torres, and Jo Ann Jackson, “A Safe and Cost-Effective Alternative Water Supply for Potable Reuse,” Meeting of the Minds, 2019; Jill Cowan, “How San Diego Gets Drinking Water from the Ocean,” New York Times, 2021; Sybil Derrible, The Silent Urban Infrastructure, book manuscript, 2022; Michaela Haas, “Purified Wastewater Is the Drink of the Future.” Reasons to Be Cheerful, 2023. ↩︎
  11. Derrible, The Silent Urban Infrastructure. ↩︎
  12. Mark DeSantis, “Artificial Intelligence for Roadway Maintenance,” Meeting of the Minds, 2018. ↩︎
  13. David A. Keiser and Joseph S. Shapiro, “US Water Pollution Regulation Over the Past Half Century: Burning Waters to Crystal Springs?,” Journal of Economic Perspectives, 2019. ↩︎
  14. Ritchie, Not the End of the World, ch. 7. ↩︎
  15. Ritchie, Not the End of the World, p. 241. ↩︎
  16. “Chemical recycling does offer us the opportunity to recycle plastics endlessly. In chemical recycling, plastics are broken right down into the basic molecular parts. This is a very pure process that stops plastics getting contaminated or degraded. The problem is that it’s incredibly expensive. Much more expensive than simply producing more plastic from scratch. That’s why companies and countries don’t do it. If we could make chemical recycling much, much cheaper then we might be able to close the loop on making new plastics. That is currently way off, but maybe its time will come.” Ritchie, Not the End of the World, p. 231. ↩︎
  17. Silpa Kaza, Lisa Yao, Perinaz Bhada-Tata, and Frank Van Woerden, What a Waste 2.0: A Global Snapshot of Solid Waste Management to 2050, World Bank 2018, p. 117. ↩︎
  18. Ritchie, Not the End of the World, pp. 243-44. ↩︎
  19. Ritchie, Not the End of the World, ch. 7. ↩︎
  20. Hugo Kugiya, “Hoovering the Ocean,” Washington Post, May 13, 2020. But see also Benji Jones, “Oops, Cleaning the Great Pacific Garbage Patch Was Probably a Bad Idea,” Vox, March 4, 2022. ↩︎
  21. Lykke Leonardsen, “Copenhagen: Designing for a Changing Climate and a Better City,” Meeting of the Minds, 2019; Ellen Braae, Urban Planning in the Nordic World, Aarhus University Press and University of Wisconsin Press 2022, ch. 8; Derrible, The Silent Urban Infrastructure. ↩︎
  22. Tatiana Schlossberg, “Turning Cities into Sponges to Save Lives and Property,” New York Times, 2022; Linda Poon, “How New York City Plans to Soak Up the Rain,” Bloomberg CityLab + Green, 2022. ↩︎
  23. Lane Kenworthy, “Climate Stability,” The Good Society. ↩︎
  24. IUCN, “The IUCN Red List of Threatened Species,” version 2022-2, 2022; Ritchie, Not the End of the World, ch. 6. ↩︎
  25. M.L. McCallum, “Verttebrate Biodiversity Losses Point to a Sixth Mass Extinction,” Biodiversity and Conservation, 2015. ↩︎
  26. Ritchie, Not the End of the World, ch. 6. ↩︎
  27. A.D. Barnosky et al, “Has the Earth’s Sixth Mass Extinction Already Arrived?,” Nature, 2011. ↩︎
  28. Ritchie, Not the End of the World, ch. 4. ↩︎
  29. Ritchie, Not the End of the World, p. 131 ↩︎
  30. Ritchie, Not the End of the World, pp. 135, 156-61. ↩︎
  31. Ritchie, Not the End of the World, pp. 161-62. ↩︎
  32. Ritchie, Not the End of the World, ch. 5. ↩︎
  33. Ritchie, Not the End of the World, p. 169. ↩︎
  34. “A key concern for consumers is their exposure to pesticides when eating non-organic food, and it’s true that organic food tends to record less synthetic pesticides. In a study across three investigations in the United States, organic foods had around one-third of the pesticide residues of conventionally grown produce. This shouldn’t surprise us. But the important question is whether we should be worried about these levels of pesticide residues. The World Health Organization has established ‘safe’ daily intake levels, where exposure has no negative effects on human health. Governments and food governance bodies then have to stick to these levels. And, in many countries, they do. A study in the US investigated the 10 most common pesticide residues across 12 food groups. They found that all foods had pesticide levels well below the limits. The majority (75%) of foods were less than 0.01% of the limit. This means residue levels were a million times lower than the threshold that would have observable effects on our health. There are similar examples from a range of countries.” Ritchie, Not the End of the World, pp. 189-90. ↩︎
  35. UNEP-WCMC and IUCN, Protected Planet Report 2020, 2021; UN Convention on Biological Diversity; Richie, Not the End of the World, ch. 6. ↩︎
  36. Ritchie, Not the End of the World, pp. 139-41. ↩︎
  37. Kaza et al, What a Waste 2.0, p. xi. ↩︎
  38. John Tierney, “The Reign of Recycling,” New York Times, 2015. ↩︎
  39. “Landfill design generally follows this process: A hole is often dug in the ground that will contain the bottom part of the landfill. The bottom of the landfill is covered with a liner so that the leachate cannot percolate into the groundwater aquifer. Pipes are added to the bottom of the landfill to collect the leachate. Environmental monitors are also installed to ensure the area surrounding the site does not get contaminated, both from methane and from leachate. Compacted solid waste is laid in the landfill and is covered with soil or dirt at periodic intervals (usually at the end of the day). A layer of solid waste and soil is typically called a cell. A series of cells that cover the entire surface area of a landfill is called a lift. Once a lift is completed, new cells are started on top of it. Structural elements called benches can be added when needed to ensure the landfill does not collapse. Once the final lift is installed, the landfill is covered with a liner to ensure that methane cannot escape…. Pipes are also installed to collect the methane that will be burned to produce energy.” Derrible, The Silent Urban Infrastructure, pp. 648-649. See also US Environmental Protection Agency, “Basic Information About Landfills.” ↩︎
  40. Sybil Derrible, Urban Engineering for Sustainability, MIT Press, 2019, pp. 572-574. ↩︎
  41. Derrible, Urban Engineering for Sustainability, figure 9.18. ↩︎
  42. Kaza et al, What a Waste 2.0, p. 18. ↩︎
  43. Kaza et al, What a Waste 2.0, p. 148; Klaus Sieg, “How Sweden Sends Just 1% of Its Trash to Landfills,” Reasons to Be Cheerful, 2022. ↩︎
  44. Kaza et al, What a Waste 2.0, ch. 1. ↩︎
  45. Kaza et al, What a Waste 2.0, p. 116. ↩︎
  46. Kaza et al, What a Waste 2.0, figure 2.11. ↩︎
  47. Kaza et al, What a Waste 2.0, ch. 2. ↩︎
  48. Kaza et al, What a Waste 2.0, ch. 7. ↩︎
  49. Kaza et al, What a Waste 2.0, pp. 148-149. ↩︎