Food for thought
Tossing the wilted kale you never got around to cooking may be a bigger contributor to climate change than throwing away a plastic takeout container. A recent study by Zero Waste Scotland found that the carbon footprint of home food waste is close to three times greater than that of plastic waste, largely because when food goes to the landfill it releases methane gas, which is even more damaging to the atmosphere than carbon dioxide.
Composting, which turns organic waste into fertilizer, is one solution to the food waste problem. Humans have been composting for as long as they have been farming. The first written reference (pdf) to compost dates to around the year 2300 BC. George Washington, the first US president and avowed gentleman farmer, spent a lot of time thinking—and writing—about compost at his Mount Vernon plantation.
But large-scale food waste collection and processing is expensive and requires participants to be diligent and well informed. Can cities get citizens to do their part or will the idea end up in the trash heap?
BY THE DIGITS
2 months: Time it takes for an apple core to decompose
450 years: Time it takes for a plastic water bottle to decompose, though plastics may never truly disappear
1.94 million: Tons of food composted in the US in 2014
29 million: Tons of food sent to landfills in the US in 2014
$1,500: Value of the food wasted each year by an average American family of four—that’s 2 million calories
2020: Year San Francisco plans to achieve zero waste
95%: Amount of food waste recycled in Seoul, South Korea today
1 billion: Number of people who could be fed on less than 25% of the food the US and Europe wastes
BREAKING IT DOWN
How composting works
While food scraps and other natural waste like dead leaves and lawn clippings will decompose on their own, composting creates optimal conditions to speed up the process. A good compost pile starts with the right mix of organic materials. The pile needs both nitrogen-rch “green” materials, like food scraps and manure, and carbon-dense “brown” materials, such as dry leaves and wood chips.
The scraps should also be small in size to maximize the surface area on which microorganisms can feast. A backyard compost pile is a mini ecosystem, with bacteria and fungi feeding on the organic matter; protozoa, nematodes, and mites feeding on the bacteria and fungi; and predatory nematodes, predatory mites, and other invertebrates feeding on the protozoa, nematodes, and mites.
A compost pile also needs moisture, either from rain or manual watering, and oxygen, which can be added by turning the pile regularly or installing aeration pipes. Lastly, the pile needs to be at least 140°F (60°C) to prevent rot.
Whether you make your own or buy commercially produced compost, the benefits (pdf) to your yard and the environment are myriad. Compost reduces the need for chemical fertilizers while adding nutrients to the soil, helping the soil retain moisture, and limiting erosion. And there’s evidence that healthy soil is crucial to addressing climate change.Continue reading