Dr. Ricky Rood's Climate Change Blog

Composting plastic: Sustainability and Climate Change (2)

By: RickyRood, 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

Updated: 1:09 AM GMT on September 28, 2011


Climate, compost, and those plastic cups: Sustainability (1)

By: RickyRood, 5:38 PM GMT on August 14, 2011

Climate, compost, and those plastic cups: Sustainability and Climate Change (1)

This past week I was at the county fair. There were science exhibits, and a display on climate-wise gardening. There was a lot of attention to garbage; it was a zero-waste event. There was an exhibit and lecture on irrigation, with, of course, some discussion of stressed and contentious water resources. After the fair I took a one-day course on grasslands and the reclamation of prairie land. There are many places where climate and climate policy fit into this mix of small activities.

I want to start with the idea of “sustainability.” When I moved to University of Michigan in 2005, I was introduced, seriously, to the idea of sustainability. I kept asking whether or not there was an accepted, single definition of sustainability. The short answer was, “no.” If you look around you find a couple of notions that are always included in the definition of sustainability. First, there is the idea that the way that we use resources to maintain our standard of living does not preclude the ability of future generations to do the same. Second, there is the idea that all of the pieces fit together into a whole. A popular notion of sustainability is “think globally, act locally”, or conveyed by the company Seventh Generation, which strives, “To inspire a revolution that nurtures the health of the next seven generations.” On a whole different scale is Ceres, which “leads a national coalition of investors, environmental organizations and other public interest groups working with companies to address sustainability challenges such as global climate change and water scarcity.” Here are some links to definitions and discussions of sustainability: @ Washington State University, Wikipedia, Environmental Protection Agency, Intergovernmental Panel on Climate Change.

It is obvious that our climate and climate change fit into the notion of sustainability, but it is not an easy relation to understand, describe and to make actionable. More directly related to our ability to sustain ourselves are population, energy, energy consumption, and standard of living. Historically we have used easy resources, because they are easy. For many centuries we were reliant upon wood for fuel and building. We cleared forests for agriculture. During the 1800s the United States was largely deforested. It became self evident that forests and whale oil were not going to support a growing population, an industrial society, and a growing economy. (A nice history of energy, and interestingly Dolly Sods Wilderness.) These sources of energy were replaced with coal and oil. All of these sources of energy have obvious, direct environmental consequences. There are also some environmental consequences that are not quite as obvious and direct; namely, those consequences due to the release of carbon dioxide.

The wealthy economies and standard of living that followed from industrialization become the priority; hence, easy energy becomes a priority. The obvious and direct environmental consequences, ultimately, become something that we try to deal with – for example, The Clean Air Act. We seek a balance of environmental pollution and industrialization – a contentious balance. Climate change is an environmental problem that is not as obvious and not as direct. It is problem where it takes, compared with a human life, a significant amount of time for the signal of climate change, of global warming, to emerge over the natural variability that we are used to dealing with. In order to mitigate climate change through the reduction of carbon dioxide emissions our “easy” choice is to quit burning fossils fuels, but that is not an easy choice to make if we humans exercise our prerogative of pursuit of high standards of living and population growth. To address climate change requires us to look out beyond the length of our lives and to see the value that a sustainable environment will have to those who follow us.

There was a couple of years ago a paper in Nature entitled, “A safe operating space for humanity”, by Johan Rockstrom and many colleagues. Here is Figure 1 from that paper.

Figure 1: “The inner green shading represents the proposed safe operating space for nine planetary systems. The red wedges represent an estimate of the current position for each variable. The boundaries in three systems (rate of biodiversity loss, climate change and human interference with the nitrogen cycle), have already been exceeded.” From “A safe operating space for humanity”, by Johan Rockstrom and many colleagues (Nature, 2009)

This figure conveys the integrated nature of sustainability on the planetary scale. An easy example to point out – climate change is, primarily, a problem of carbon dioxide emission, as is ocean acidification. Hence, from an integrated perspective, the two cannot be looked at in isolation. But looking around the circle, all of these environmental issues are related. They are all related to population, energy, consumption, standards of living and robust economies.

I started this entry, this series, with a very mundane event – being at the fair. At the fair we talked about water, and sure climate change might be important to water, but it does not seem as immediately important as the cities’ thirst for water and the purchase of agricultural water rights (Thirsty Cities, Dry Farms). This interface of climate change on this local level is real, it is contentious, and it is substantive. Yes, I have started another series, and in it I will look at “think globally, act locally.” Yet another problem of many scales that must be addressed as we adapt to global warming.


Climate Change Sustainability

Updated: 8:21 PM GMT on August 14, 2011


Is this year what we can expect?

By: RickyRood, 6:38 PM GMT on August 03, 2011

Is this year what we can expect?

In recent weeks a question I have been asked often, “is this year, the last couple of years, like what we can expect in the future?” The question is often asked quietly, perhaps by a planner, say, someone worried about water in their city. The question follows from not only a perception that the weather is getting “weird,”, but also some small aspect of experience in their job. For example, a water manager recently said they were seeing their local river showing a distinct change to sporadically high flow in the winter, smaller spring flows, and extremely small flow late in the summer. Is this what I should expect in the future? The short answer is yes.

This question of expectation has rolled around in my head for years. I am a gardener with aspirations for small farmer. Over the last 30 years, I have definitely pushed my planting earlier in the year. When I was in Maryland, I felt wet, cool Mays were becoming the “norm,” with my tomatoes sitting in sodden soil. At the same time I would recall plots I had seen in some recent presentation that showed modeled shifts in the warm-cold patterns suggesting springtime cooling in northeastern North America. These are the sorts of casual correlations that lead people to think are we seeing a new “normal.”

In 2008 I wrote a blog about the changes in the hardiness zones that are reported on the back of seed packages. These are the maps that tell us the last frost date, and there were big changes between 1990 and 2006. These changes in the seed packets caught the attention of a lot of people. Recently, NOAA published the “new normal.” This normal relies on the definition of climate as a 30 year average. (AMS Glossary) What was done - at the completion of the decade NOAA recalculated a 30 year average. That is, 1981-2010 rather than 1971-2000. This average changed a lot, with notable warming of nighttime minima. There was some regional reduction of summertime maxima; that is, cooling. All in all, the average temperature went up, with most of the increase in nighttime minimum, a fact that is consistent with both model simulations and fundamental physics. This also came with another update of those hardiness zones.

When trying to interpret climate information and determining how has climate changed and how will it change, the combination of observations, fundamental physics, and models provide three sources of information. The combination of this information and the determination of the quality of that information is subject to interpretation. In the case of determining whether or not we are already experiencing the climate of warming world and how that change will be realized in the next decades it depends on how we use the models.

In my previous entry on heat waves, I implied how to use these pieces of information together. There are fundamental physics in the relationship between temperature and moisture in the air; hot air holds more water; warm water evaporates more quickly. The question of the model is - how well does the model represent the movement of that moisture? For the heat wave example, it is important how well do the models represent persistent high pressure systems over North America in the summer? Are these high pressure systems represented well by the models for the right reasons? The answer to the model question has a range of answers. The model does represent these systems, but if you are an expert in summertime persistent high pressure systems, then you can provide a long list of inadequacies. How can we glean information about the quality of the model? If we look at weather models, then we were able to predict the heat wave – even with the inadequacies that the expert or skeptic can list. Returning to the climate model, do we see like events in the current climate, and do these events change as the planet warms? The answer is yes. Then can we use this to guide our development of plans to adapt to climate change? The answer is yes, if we can connect the model back to data and the fundamental physics. This does become a matter of interpretation – how strong or weak is that connection?

The more I work with planners the more I hear the need for interpretive information, expert guidance, advisories about climate and climate change. People start with the notion that they want digital data from climate models that looks like current weather data. Once presented with 1) the logistical challenges of using that data, 2) the complex nature of the uncertainties associated with that data, and 3) the relative importance of climate to other parts of their decision package – once presented with these facts, they move to the need for advice. This makes sense - most of us want a narrative weather forecast, rather than model output. And the models play the same role in the use of weather forecasts as they do in climate projection. The models guide our thinking, with the ultimate forecast based on that guidance refined by observations and fundamental physics.

This entry started with the question I hear more and more – is this year what we can expect more of in the future? I have a mantra which is that on average the surface of the Earth will warm, ice will melt, sea level will rise, and the weather will change. What we are seeing here is weather changing in a warming, more energy laden, environment. The extraordinary extremes that we have seen in the last year and are seeing this year are quite solidly connected to both fundamental physics and the guidance from climate and weather models. Hence, my answer, as I walk around my garden, thinking how to get better tomatoes next year, thinking about my irrigation system in my doddering retirement, is yes, what we are seeing this year tells me about what to expect in a future that is relevant to me - not something far off.


Climate Change Extreme Weather

Updated: 4:29 AM GMT on August 04, 2011


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

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Dr. Ricky Rood's Climate Change Blog

About RickyRood

I'm a professor at U Michigan and lead a course on climate change problem solving. These articles often come from and contribute to the course.

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