The virtues of composting are so obvious that it's shocking it isn't practiced more commonly. However, I can sympathize with composting's inherent conflict with the nature of modern 21st century society (and full disclosure here: I certainly don't compost nearly as much as I could). Composting is about dealing with waste -- not necessarily rotting, gross, stinky waste, but waste nonethless. Composting is not convenient -- it doesn't consume a lot of time and you don't have to go out of your way to compost, but it does take some thoughtfulness. Composting is not glamorous -- it's not very sexy to say that you are saving your veggie scraps for your worms or to carry a handful of banana peels out to the tumbling composter in the backyard. And while composting is not difficult, it takes more effort than tossing a glass bottle into the recycling bin.
So, why should people bother? In a way, composting just makes sense. When composting, all that the human is doing is facilitating what would have happened naturally, had we not covered all the dirt on the ground with asphalt. The way the world operates now, trash is kept off most visible surfaces (as we all prefer, myself included) and piled into giant dumps we call landfills. When a landfill reaches capacity, it is covered with dirt to allow the natural process of decomposition to begin (granted, it may literally take hundreds of years). What we call "dirt" is actually the broken-down remains of organic matter. It is chock full of microorganisms such as bacteria and fungi, which actually perform the important task of decomposition. It also contains nutrients that were originally contained within the decayed organic matter. As one might imagine, not every pocket of the waste in a landfill would come into contact with the decomposers in soil. Moreover, deep within the center of a landfill waste mound, there is often little or no oxygen to support the microbes that break down waste aerobically. Instead, anaerobic bacteria take over. Their main metabolic byproduct is methane, a greenhouse gas with a global warming potential that is 21 times worse than carbon dioxide, according to the EPA (not to mention it smells like, well, fart). In summary, the many shortcomings of using a landfill as a waste disposal destination are that it sucks up land (one of Earth's most precious resources) while enabling anaerobic decomposition to occur on a large scale (greenhouse gas -> climate change + stinky).
Household composting, then, is really about diverting waste from the landfill and creating favorable conditions for waste decomposition by aerobic bacteria to occur naturally. There are a few different ways to do this, which I won't go into today. What I do want to spell out are the benefits of household composting.
1. Composting reduces waste = less land needed for landfills. A no-brainer, really. According to Waste Management in its 2006 Annual Report, our existing landfills had an average of 28 years left at that point. At the same time, more than 34 million tons of food waste was generated in 2010 in the U.S. Food waste is the single largest contributor to landfills and incinerators. If we can divert most or some significant fraction of this by composting, we would increase the longevity of our existing landfills and save land for other purposes (like growing food).
2. Composting helps slow down the climate change trajectory. As mentioned previously, organic waste sitting, buried, in landfills is essentially a methane producing factory. Yes, some landfills manage to capture that methane and convert it into fuel. However, until that becomes standard practice at all landfills, the better option is to simply prevent organics from ending up in landfills by composting them.
3. Composting helps protect bodies of water from eutrophication and algal blooms by producing awesome fertilizer. Have you ever seen ponds covered in slimy goo of an unnaturally green color? Worse, have you seen dead fish floating on top of such a pond? Here's the deal: modern agriculture is aided by the liberal use of synthetic fertilizers and pesticides (with the exception of organic farming) but is necessarily coupled with deforestation. Rain can and do wash loose fertilizer- and pesticide-laden soil into large bodies of water such as lakes, rivers, and oceans. The assault of soil itself can already do plenty of damage to aquatic and marine organisms. However, it gets worse. When all the nitrogen and phosphorous in fertilizers enter an aquatic ecosystem (a process called eutrophication), they can trigger massive population explosions in existing communities of algae (AKA algal blooms). This population spike is, logically, unsustainable, and most of the algae end up dying, turning their previously pristine homes into a garish green nightmare. Bacteria, being decomposers that feed on dead organic matter, will feast on the algae carcasses and in turn undergo their population boom. However, unlike photosynthetic algae which produce oxygen as a metabolic byproduct, these bacteria use up oxygen (as we do), to the point of depleting the supply in the local ecosystem. Once depleted of oxygen, a pond/lake/river becomes a dead zone.
Where does composting come in? Composting produces truly excellent, natural fertilizer, with pesticidal qualities. The use of vermicompost, which are castings produced by earthworms, suppresses disease in plants, improves flavor, and increases crop yield in some cases (by 20 percent for certain crops in one study!). If food waste is systematically composted, the agricultural industry would not need to use synthetic fertilizer (the production of which opens up a whole other environmental controversy). Ideally, most or all agriculture would be "organic," using compost as a fertilizing agent.
Composting results in many, many other environmental and social benefits. Lest this blog post becomes a book, we'll save them for another time. I don't expect everyone to start composting tomorrow. I would readily confess that I myself don't compost everything I could. However, if composting is something you've been thinking about doing anyway, I hope this post gives you the final kick you need to get started.
Vote to make composting possible for everyone in Los Angeles, especially our schools! http://myla2050.maker.good.is/projects/cityearthworm