Compost as Solution to Reduce Greenhouse Gas Emissions

Reader Contribution by Brian Frank
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Putrefaction. Fermentation. That’s what vegetable scraps in a kitchen garbage or landfill go through. It’s also called anaerobic decomposition, which occurs in oxygen-poor environments. As “putrefaction” implies, this is a stinky process. Yet much of the Western world puts vegetable scraps in a kitchen can and thinks nothing of it until it’s time to tie up that fetid, hot, weeping plastic kitchen garbage bag and drag it out. Putrefaction’s end products are methane, carbon dioxide, ammonia, organic acids, and heat.

Carbon dioxide is not the only problem. Methane is the problem, too, says Sally Brown, PhD, an environmental researcher and author of Carbon sequestration in urban ecosystems (Springer, 2012). I corresponded with Professor Brown by email about her research. Methane is not “clean” despite what fossil fuel companies’ commercials say when they are selling natural gas.Methane is 30 times more potent than carbon dioxidein its heat-trapping ability over a 100-year timeframe. And atmospheric methane levels are rising faster than carbon dioxide, according to NAOA. Decreasing methane emissions is the number one reason composting is important.

Compost Depends On an Oxygen-Rich Environment

Professor Brown says we should be composting vegetable scraps rather than sending them to kitchen garbage cans and landfills. A ton of food scraps sent to compost rather than a landfill prevents the emission of the equivalent of one ton of carbon dioxide into the atmosphere — of course, with a lot of variance based on what materials went into the compost.

Unlike decomposition in a landfill, which occurs without oxygen, composting requires an oxygen-rich environment. Composters have openings for oxygen to enter as opposed to air-tight garbage cans and compacted soil-covered landfills.  Compost piles should be small to moderately sized so that they can be turned over to create oxygen-rich pockets allowing the aerobic microbes that degrade vegetable scraps to breathe. My composter, the one in the photo, is on rollers allowing the contents to be rolled over to mix it with air.

The are benefits with this process, aerobic decomposition. Aerobic microbes breathe like we do. Like us, their respiratory end products are carbon dioxide, water vapor, heat energy and, in their poop, ultimately minerals. Plant-accessible minerals make soil healthier. Healthy soil means healthier plants. Healthy plants photosynthesize more carbon dioxide, removing it from the atmosphere.

Reducing Fertilizer-Related GHG Emissions

There are other carbon dioxide-reducing benefits of composting. Using compost as fertilizer eliminates the need for commercial fertilizer. This eliminates the carbon dioxide emissions incurred by commercial fertilizer manufacturing. Adding compost to soil is a way to return carbon to earth’s solid part where 99.96% would normally be stored.

Composting doesn’t just return carbon to the soil — it recycles nutrients. Think about it: We grow corn. We eat the kernels and send the husks and cob to the landfill. The husk and cob also contain the nutrients nitrogen, potassium, calcium, magnesium, sulfur, chlorine, iron, boron, manganese, zinc, copper, and nickel. We have removed nutrients from the earth and locked them in a toxic landfill where we can never use them again. It’s not sustainable.

Composting is practical. A composter is outside the house. This eliminates fruit flies in the house, the reason I was forced to get one originally. Plus, the kitchen garbage won’t get so smelly. There’s also less trash volume. Less garbage to cart away means reduced fuel and emission costs with transporting it, less financial burden on municipalities. Less trash means smaller landfills, another urgent need. The constant growth of landfills is not sustainable.

Compost Has Its Caveats

Unfortunately, sustainability is not yet a common value. Few policymakers, albeit a growing number, even use the word. Still, many of us feel the need to do good. We use the word “organic” unaware that to be organic, a practice should also be sustainable but is not always under legal definitions.  Therefore, a kind of, what I call, “organic dissociative schizophrenia” has emerged.

For example, the pesticide-free organic banana which finally doesn’t contaminate compost comes with a plastic label whichwill contaminate compostwith microplastics or nanoplastics during the 400-year plastic degradation process.  Regarding this, Sally Brown, PhD issues a caveat to the well-intentioned composter.

First, be careful to remove all the plastic labels from vegetable scraps before putting them in the composter.  Second, action is needed to change how food — really all things — are packaged. This is the next be wave. She says ultimately our economy should be driven less by spending on “stuff” and more on the intangibles that matter. Three hundred dollars spent on a good night out on the town is better for the environment than six synthetic, multicolored hoodies which will end up in a landfill. I’ll see you out on the town.

Brian Frankreports on environmental issues locally with a passion for using numbers to define sustainability challenges and solutions. Connect with him on his blog, Subsurface Stories, and read all of Brian’s MOTHER EARTH NEWS posts here.

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