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Composting plastic: Sustainability and Climate Change (2)

By: Dr. Ricky Rood, 5:33 AM GMT on August 29, 2011

Composting plastic: Sustainability and Climate Change (2)

It has been a challenge in the realm of WU’s climate change blogger. Sick computer, and on Tuesday I was giving a talk at the Climate Program Office when the great D.C. Earthquake came. It was a webinar, and, within a minute, savvy scientists were reporting, “5.9, Mineral, Virginia.” The earthquake, which I had successfully identified in my talk, eliminating both “train” and “terrorist attack,” led to a natural separation of those who went to doorways in the interior of the building and those who went to the large picture window and said, “cool, all the buildings are shaking.” This was followed by building evacuation, and a typical D.C. response of gridlock and people walking away from wherever they were, with perhaps, the assumption that wherever they were walking to was safer. Considering all of the fallen stones and bricks, it is quite fortunate that people were not seriously injured.

This was, of course, followed by the march of Hurricane Irene up the coast, which leads to a certain type of hurricane-anticipation hysteria. I believe that the Weather Channel and CNN amplified this hysteria with exaggerated and unwarranted statements of the lack of historical precedents for such a storm. There is perhaps an over reporting of people on beaches in a spot light saying, “It is only going to get worse.” Is this the way to get people to take these storms seriously? Anyway, the storm came ashore near my old stomping grounds on the Neuse River where I hear there were nearly 8 foot surges. This was at the end of the funnel, and it is the funneling of water up the creeks that make for the greatest flooding. It will be another billion dollar storm.

Still … I have started this blog three times and my sick computer has destroyed it. I want to get back to sustainability, composting, and those plastic cups.

Let me start by saying that I recycle. I will toss plastic cups in my luggage to take them to a place that will recycle, say, number 6 plastics. My father had me separating metals and pulling nails from miles of lumber in the 1960s for reuse. That said, I have been confused by corn-plastic, compostable plastic cups. If you take one of these cups and put it in your compost heap, well, it doesn’t compost. If you think about plastics and plastic making, then you’re not really sure what it might compost into. So you call and ask about this, and they say they were designed for commercial composting facilities, which operate at high temperature in carefully controlled environments. Then you find out that your municipality does not do such composting, so you are left with a cup that can’t be recycled, will not be composted, and to a naïve person like me seems like garbage. It’s garbage, when it could have been a recyclable number 1 plastic cup. This opens up all sorts of opportunities for greenwashing and the pursuit of irritating, good-intentioned, ineffective environmental policies and practices.

Irritating: I have been on the edge of a couple of zero-waste events in the last couple of years. One of the places where cities and counties exercise zero-waste policies is street festivals and county fairs. These are often places where there are traveling vendors, and a mix of activities that range from demolition derbies to face painting to costumed goats and prized cattle. There is eating of odd food. The point, there are a lot of people that are perhaps, not of the zero-waste jurisdiction or culture. One source of tension is those plastic cups. Let’s say they cost a little more, but let’s assume that if the event is in a place that supports zero-waste events, then people will pay a little more for their lemonade. The requirement to use compostable cups has some practical issues. They might not fit lemonade making equipment; they don’t stand up to heat; they require special stocking. They challenge some people’s view that the market price should determine what they choose. And, given where I started above, that they don’t seem so compostable, they challenge sensibilities. That list looks a lot like the range of responses to addressing the climate-change problem.

Sustainability: Sustainability is about a lot more than climate change. It is about landfills and soil management and energy use and all of those resources that we need to support ourselves. So in that sense, climate change, or let’s be precise, the emission of carbon dioxide, is a subset of sustainability. There are a lot of things that can be done in the spirit of sustainability that don’t address the emissions of carbon dioxide. For example, if you focus on energy security, some would argue that coal would address our needs long enough to get by, and hence would argue that coal is part of a sustainable energy policy – same with tar sands. Both coal and tar sands contribute to more and more carbon dioxide emissions; hence, they are in the long run agents that will lead to, for example, several meters of sea level rise. There are many initiatives in the efforts to promote sustainability, that don’t obviously help climate change. (Think about the locally grown apple kept in refrigeration for 8 months versus the apple from Australia that is not stored as long. Think about the electric car that charges up from the coal power plant.)

Composting: I’ve composted for years – let me restate that, I have composted vegetative matter for years. As a kid we did not call it composting, but we piled up mountains of leaves inside of a large fenced area and then used it gardening. It makes sense to a gardener, but it also makes sense to someone whose father was the mayor of a town and challenged with what to do with a lot of leaves and not really wanting to promote backyard bonfires on dry October days. So composting leaves and garden waste makes intuitive sense, but what about prescribed policies on composting of food waste and yard waste and, maybe, scraps of lumber? Again, if you are a city then you want to control the amount of garbage you have to deal with. Garbage is expensive – buying land, transporting it, burying it – so you start to think about what might composting do for my garbage problem. There are several ways that that leads to plastic, because plastic has infiltrated everything we do, and it lasts practically forever. Also, it comes from oil. In some sense, plastic is a lot like carbon dioxide. Perhaps thinking about plastics and waste plastic is a good way to think about carbon dioxide waste, because we can see plastic waste everywhere. But I digress.

This is a blog about climate, so let’s bring the composting and climate together. It is easy to make the casual argument that composting in your backyard is good for climate change. Or, at least, it might be. One of the climate benefits of composting in your backyard comes from not trucking the stuff away. So if you buy a gas-powered chipper or shredder, you’re likely to do away with that benefit. I’ve had a number of student projects looking at composting and climate change, especially composting food from cafeterias, and the answer is complicated. One of the big factors in the composting equation is transportation. If you have to ship the stuff many miles out of town, it’s not likely composting will help climate change. But if you can keep it nearby, have a good commercial-scale facility, and can start with a clean stream of compostable material it can help a lot. It helps a whole lot when you realize that if buried in a landfill, it usually makes methane. (To imagine how complex this gets, sometimes it is better to dump the waste in the sewer and let the sewage experts deal with it, and often, the best thing to do is to burn it for fuel. So it is not an easy calculation and decision.)

So back to those plastic cups. I try to be a responsible blogger so I did a little research. I hope I did enough research to not make a fool of myself. I put some links to articles down at the end of blog. I want to line up some conclusions, but, first, the observation that most of the work investigating plastics in waste streams that I found was coming from Northern Europe, China, and Africa. OK some conclusions. I was right that some of those plastic cups don’t break down in home composting. Home composting is simply not active enough to break down those cups. At best they become some sort of plastic sand. But other plastics and compressed papers break down pretty well even at home. In commercial composting, where there is a lot of stirring and a lot of biodegrading going on, they breakdown pretty well, and they don’t do anything bad to the compost. And at street festivals and fairs, if there are compostable cups, then when people throw away all of their eating stuff in the same garbage, which people are prone to do, then the compostable cups (and forks and plates) clean up the stream for the much larger mass of food waste. Therefore at big events, cafeterias, and restaurants, the compostable cups can have a large impact on waste management – but it does require an easy and visible and clearly marked place to put compostable garbage.

Above I said that zero-waste and compostable cups can challenge one’s sensibility. The effort I have gone through here is more effort than the average person is going to exert to worry about their garbage. I am sure that some of the people I know who find the zero-waste policy, perhaps, silly, would find that it makes sense when you think about the stream of compostable material made possible by compostable cups. But as often presented, in the absence of information, in the spirit of prescriptive policy that is “good” in some sense, it serves to discredit the whole culture of sustainability. It poses “good” and suggests that what others are doing is “bad.” And inevitably here in the good ol’ USA of 2011, it becomes a matter of politics, of culture.

But this is a blog on climate change. What about the compostable cups and climate change? So if the impact of the compostable cup on climate change is measured by its carbon footprint, then the difference between the compostable cup and old-fashioned plastic cup is hard to determine. If a locality is set up with a good commercial-grade composting facility that is not far away, then the impacts can be substantial. In one of my students’ projects, composting food waste from University of Michigan cafeterias was the equivalent of removing 100 cars from the road. In this situation, the compostable cup cleans up the compost stream and allows the food to be composted. But, in any case, what is best for the climate is to use metal utensils and washable plates, and to wash the dishes. And if a business or town hands out compostable cups WITHOUT a composting plan and facility, they mess up their recycling program as the cups get mixed into the recycling stream.

It’s never easy. I am often asked what individuals can do about climate change. It is “be efficient,” use compact fluorescents, composting and recycling can be good, insulate, insulate, insulate. Sometimes I say quit being an eco-tourist. In the end though, assuming we consume as we view our prerogative to consume, we must de-carbonize our energy. We must quit making so much of our stuff to be disposed. All of the little steps are important; they might raise our awareness; they might make us feel better about our consumption; they buy us a little time – maybe, but they cannot solve that big problem of burning coal, oil, and natural gas to supply our wealth. As long as we are not thinking about our energy use and our energy waste, we are not really addressing the zero-waste and sustainability issues of climate change.


Razza et al., Compostable Cutlery …

Song et al., Biodegradable and compostable plastics …

Hopewell et al., Plastics recycling …

Mohee and Unmar, Determining biodegradability …

Rockstrom et al., A safe operating space for humanity

Climate Change Sustainability

The views of the author are his/her own and do not necessarily represent the position of The Weather Company or its parent, IBM.