Will We Ever Be Able to Clean Up All Our Trash?
We die and decompose, but a growing portion of our garbage lives on. Your great-grandfathers bones have become organic matter in the soil, but the same cannot be said for the Mr. Goodbar wrapper he discarded 80 years ago today. Our landfills are poorly organised museums, robustly endowed and expanding by the second. Some, of course, have hit full capacity, and now host only historical trash. Which would be fine, even interesting, if wed found some way to stop producing garbage instead of generating exponentially more of it. I suppose we could set up some kind of lottery system whereby each year, one small American town is displaced, bulldozed, and converted to a garbage dump. But, the way things are going, even that might not be enough. For this weeks Giz Asks for Earther, we reached out to a number of experts to find out. Emeritus Professor, Paleobiology, University of Leicester, and author of The Earth After Us: What Legacy Will Humans Leave in the Rocks?, among other books  Our landfill sites are enormous, and growing rapidly. A few may become resources in the future, if they contain enough metals or other useful materials. But, its unlikely that well clean up more than a small fraction of them, either for profit or the good of the planet. As for the rest, nature will ultimately clean them up. This kind of cleaning up might produce some amazing far-future fossils, but before that, some of the results wont be pretty. There are two ultimate fates for a landfill site  a mass of garbage that may be square kilometers in size and several tens of meters thick. Firstly, it might simply be buried, and stay buried for many millions of years. This kind of process can happen on a subsiding delta or coastal plain, like that of the Mississippi. The landfill site will become ever more deeply buried by masses of sediment, ultimately perhaps reaching several kilometers below ground, being compressed, heated, and perhaps crumpled by underground movements of the earths crust. The contents  aluminium cans, chicken bones, plastic bags, discarded mobile phones and all the throwaways of human civilisation  will be transformed into myriad extraordinary technofossils that (if the petrified landfill is ever pushed up to the surface again by earth movements) might become an object of wonderment by some far-future palaeontologist. This new kind of rock will be bizarre, but probably by then largely harmless: toxins will have decayed, and plastics transformed into brittle coal-like stuff. The other kind of natural clean-up is more immediate  and more damaging. Landfill sites that are not geologically buried will, sooner or later, be eroded by the action of wind and winter  especially those near the coast, which that the waves and tides bite into as sea level rises. The garbage from them is exhumed, released back to the surface, and then carried by currents, often to distant coastlines and the deep ocean, endangering humans and other living organisms. This process is already underway in many places around the world (it can be seen in a walk along the Thames estuary, for instance). It is a big, and growing, factor in the evolving relationship between our cast-offs and the planet. Landfill sites that are not geologically buried will, sooner or later, be eroded by the action of wind and winter  especially those near the coast, which that the waves and tides bite into as sea level rises. The garbage from them is exhumed, released back to the surface, and then carried by currents, often to distant coastlines and the deep ocean, endangering humans and other living organisms.  President, Beyond Plastics, and Former EPA Regional Administrator  Americans generate a tremendous amount of solid waste, and that waste has very significant environmental justice and climate change impacts. The fundamental problem is that, in the U.S., our consumption patterns are not sustainable. The U.S. has 4% of the worlds population; meanwhile, it uses 17% of the worlds energy, gobbles up 24% of the worlds natural resources, and  not surprisingly  creates 12% of the worlds solid waste. What we really have to do is reduce the generation of packaging, which makes up close to half of municipal waste. Plastic packaging, in particular, is a problem, because it never biodegrades in a landfill, and if its burned in a garbage incinerator it creates air pollutants, including dioxin. Despite all this, plastic production is growing at a rapid rate. One engineering approach to this problem is called landfill mining, which involves going into old landfills and trying to pull out material. Im not particularly optimistic about this approach  I do think theres value in pulling out some metals and glass, but the issue is that when you crack the covers of lined and capped landfills you can end up releasing large amounts of methane gas. You also dont want to be digging up cardboard and paper thats in the process of biodegrading. And thats not to mention the fact that theres a lot of hazardous waste in municipal landfills. Landfill mining was kind of the latest, most interesting thing about 15 years ago, but at this point there isnt much of it going on, which is, I think, a good thing. Instead of landfill mining, I would advocate strongly requiring companies to redesign their packaging to make it refillable and reusable. In situations where thats not possible, recycling is second-best. Unfortunately plastic recycling has been an abysmal failure: weve reached a rate of only 8.5% in the U.S. And we should not forget about composting. The exciting thing about composting is that about 40% of the American waste stream is food waste and yard waste. The way to deal with all this waste is, first, to follow your parents advice and finish whats on your plate; to donate what you dont eat to homeless shelters and social service agencies; and to send the rest to compost operations. If you keep the universe of that waste stream very limited to just yard waste and food waste your composting operation is going to run beautifully. Most communities in the U.S. dont make it easy to compost yard waste and food waste, which is precisely the material you need to keep out of landfills, because when it biodegrades and decomposes in landfills it forms methane gas, and thats a potent greenhouse gas. The fundamental problem is that, in the US, our consumption patterns are not sustainable. The US has 4% of the worlds population; meanwhile, it uses 17% of the worlds energy, gobbles up 24% of the worlds natural resources, and  not surprisingly  creates 12% of the worlds solid waste.  Visiting Professor in Resource and Waste Management at Imperial College London, lead author of the United Nations Environment Programs Global Waste Management Outlook, and co-author of UN-Habitats Solid Waste Management in the Worlds Cities  The planet is indeed facing a municipal solid waste or garbage crisis. Around 40% of the world population do not have their garbage collected and are forced to manage it themselves by wild dumping and open burning. Even when the garbage is collected, much goes to uncontrolled disposal. So, the first priority must be to bring garbage under control, by extending collection to all and by replacing uncontrolled dumping and open burning with controlled recovery and disposal. Not only will this have massive benefits for public health and the local environment, but will also cut by half the estimated 10 million tonnes of plastics entering the oceans each year, and reduce global greenhouse gas emissions by around 5% (by cutting both methane emissions from dumping and black carbon from open burning). A second priority is to move beyond controlled disposal to more sustainable management options. These start with waste prevention, for example designing products and packaging for longer life, repair, reuse and easy recycling, and changing our behaviour to reduce avoidable food waste; segregating wastes at source and collecting materials separately to maximise both dry material and organic recycling; and then considering waste-to-energy or landfill for the much-reduced quantity of residual garbage. Many developing countries already have a thriving informal recycling sector, which can be built on to reduce the cost of bringing wastes under control. So, yes, with a massive global effort backed by all countries and commercial organisations, we can look forward to a time when we have cleaned up the planets garbage. But until we turn off the tap and begin to manage properly the estimated one billion tonnes of garbage (around 50% of the total) which is currently unmanaged or mismanaged every year, and then reduce the quantities that need to go to high standard landfill sites, it would seem a bit futile to focus resources on trying to clean up every old landfill site on the planet. With a massive global effort backed by all countries and commercial organisations, we can look forward to a time when we have cleaned up the planets garbage.  Clinical Professor, Environmental Public Health Sciences, New York University, who studies lead and toxic wastes to design safe and evidence-based solutions to environmental pollution  Id say cleaning up the landfills of the past is too risky  its probably best to just leave them there. Once garbage is in the ground, digging it up and re-sorting it is very challenging, and presents a serious public health challenge, one which could be disastrous because of the potential for exposure. You have stuff thats been in the ground for years  some of it is decayed, some of it is wet, some has mould on it. And there are other complications. Take New York: La Guardia and Kennedy airports are both built on landfills, so digging those up is impossible. I think the key, then, is to stop putting things in landfills that we could completely recycle. Were still putting a lot of plastics in landfills that shouldnt be there. That said, things have improved. By and large, over the years, weve sent less and less to landfills, because our recycling is so much better. But ultimately something like a cereal box or a pizza box, or leftover food  all of that goes into landfills. We can try to chop up our cereal boxes and eventually compost them, but thats a lot of material. And most of whats in an average trash can is not compostable. So the old landfills in Pennsylvania, New York, Illinois, etc. are probably going to stay there, and eventually, hopefully, theyll be turned into nice parks or other green spaces. As things stand, theyre not really hurting anybody, and Im worried that, by opening and emptying them, wed cause more damage than benefit. Its also worth mentioning that, in some poor countries, landfills are major employment sites. Theres an organised pecking order: some collect glass, some collect aluminium, some collect metals. Theres a huge historic landfill in Senegal, Mbeubeuss, that supports tens of thousands of scavengers. At the same time, some of these landfills get so big that they collapse, resulting in fatalities. So its a catch-22: you dont want to close jobs for needy people, who are ultimately doing some good for the planet through recycling, but the risks from collapses and chemical exposures are pretty serious. So the old landfills in Pennsylvania, New York, Illinois, etc. are probably going to stay there, and eventually, hopefully, theyll be turned into nice parks or other green spaces.  Professor of Geography, Memorial University of Newfoundland and Labrador, whose research investigates where and how contemporary discards are made, where they travel, and where their effects accumulate for whom and under what conditions  If clean up means something like disappeared or made benign, then no, thats a fantasy. Given sufficient time, all landfills leak and spill. We can temporarily sequester garbage. We can move it around from place to place and medium to medium, say land deposition to atmospheric deposition, but we cant make it all go away, because there is no ultimate away. Except for landfills that have been closed to further use  like Fresh Kills in New York City  todays landfills arent fixed volumes of deposited garbage. Theyre growing. To clean them all up, one would have to imagine a clean-up process that can work faster than the rate of deposition in operating landfills and in historical ones now closed. Thats a contradiction in practice in an economy premised on growth. The issue of clean up isnt just about tonnage. Its common to think of seemingly exotic garbage like nuclear waste as uniquely long lived, but a lot of materials that commonly head to landfills, such as certain plastics, will persist for as long or longer than radioactive materials. Also, many things that make their way into landfills today are heterogenous amalgams of materials that, as of now, have no known way to treat them beyond deposition. There is literally no technical way yet to reuse or recycle some amalgams of plastics, metals, or chemical compounds commonly found in landfills. Perhaps there is a future in which some form of technology is invented that can mine and re-engineer all currently landfilled materials. Even then, given current understandings of physics, that would require inputs of materials and energy and those have to come from somewhere. Even if they were to come from the landfills themselves somehow, one would have to imagine them being converted into beneficial, rather than harmful substances in the process. So, in a very real sense the idea of clean up is science fiction. None of this is to say that because clean up is impossible people shouldnt do everything that can to mitigate garbage. But genuine clean up would mean dealing systemically with how garbage is generated in the first place. To clean them all up, one would have to imagine a clean-up process that can work faster than the rate of deposition in operating landfills and in historical ones now closed. Email us at [email protected]  Editors Note: Release dates within this article are based in the U.S., but will be updated with local Australian dates as soon as we know more.