Don't Underestimate the Carbon-Capturing Power of the Most Basic Backyard

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You'll never look at the typical suburban backyard the same way again. (Photo: Syed Abdul Khaliq/flickr)

Overwatered, drizzled with chemicals and manicured with emissions-belching machines, the front lawns and backyards of suburban America tend to get a bad rep. And much of the time, it’s deserved.

University of Wisconsin-Madison Ph.D. candidate Carly Ziter would probably argue, however, that meticulously groomed residential green spaces aren't completely without merit.

Yards and gardens are indispensable in helping to mitigate the effects of climate change. The soil acts as a potent secret weapon, pulling harmful CO2 emissions from the air and trapping it. This isn’t exactly a new revelation. Yet according to Ziter’s research, published in the journal Ecological Applications, the soil of developed land — a category that includes not just residential lots but also similarly resource-intensive golf courses and cemeteries — is better at absorbing carbon than the soil found in open natural spaces like native grasslands and even forests.

As reported by the New York Times, the carbon-sequestering capabilities of residential green spaces like lush front lawns might come as a surprise to those who've written them off as being mostly for show and not necessarily beneficial to the environment; an outdated American ideal that largely serves as a pretty-to-look-at way to keep up with the Joneses. As such, most research into how urban and suburban green spaces can effectively counter climate change has focused on parks, arboretums and other large, tree-studded areas, not smaller, private residential spaces.

"But what we realized is that people’s backyards are a really big player here," Ziter tells the Times.

Carly Ziter collecting samples
Carly Ziter of UW-Madison collects soil samples in a backyard. Her research aims to highlight the importance of urban green spaces, even small residential ones. (Photo: University of Wisconsin-Madison)

A rare bit of love for lawns

In her research, Ziter collected soil samples from 100 different sites across Madison, Wisconsin’s second largest city with a population just over a quarter of a million. The sites included a wide range of open spaces such as urban forests, grasslands, parks and residential lots, the latter of which covers roughly 47 percent of the lively lakeside city.

"I had to get permission for every single one of my hundred sites within the city,” Ziter says of the collection process in a UW-Madison news article. "And that meant speaking one-on-one with upwards of 100 people, and that’s everyone from Joe Next Door to the golf course superintendent to a church group that manages a prairie restoration."

After studying the samples, Ziter concluded that soil from the most unsuspecting type of open spaces — developed land like residential yards, golf courses and public parks — store significantly more carbon emissions than more natural areas. The soil in forests and other undeveloped open spaces were found to be better at absorbing water runoff, which prevents flooding.

It’s unclear why the soil of yards and lawns trumps the soil of forests when it comes to carbon absorption. Ziter, however, thinks it has something to do with the way we engineer and manipulate residential green spaces. As the Times observes: "So there is a risk that the carbon we release using gas-powered lawn mowers, for example, could eclipse the soil’s ability to absorb carbon."

Subdivision backyard
When it comes to mitigating the effects of climate change, anything's better than pavement ... even a patch of backyard grass. (Photo: r. nial bradshaw/flickr)

This isn’t to say that we shouldn’t clear urban forests and replace them with vast expanses of sparkling green lawns. Things growing above the soil, namely trees, also sequester carbon while providing a range of other environmental benefits. Forests are perhaps the most vital, hardworking carbon sinks we have — it just happens that their soil isn’t as good as capturing the bad stuff.

If anything, Ziter’s research goes to prove that urban green spaces are a crucial tool in the fight against climate change, even if they take the form of modestly sized, immaculately manicured backyards. Pavement is the enemy.

"You don’t need to have a perfect lawn for it to be really beneficial," Ziter tells the Times. "You don’t have to have an incredibly intensive management system. It’s O.K. to have things to be a little wild."

On that note, backyard "carbon farming," the act of planting an abundance of specific (and often edible) plants to better absorb CO2 emissions, is one way to radically transform your residential green space from an environmental nightmare to a finely tuned carbon sequestering machine.

"If you’re out gardening, you’re interacting with the natural world. If you’re going out for a walk along the lake, you’re interacting with the natural world," Ziter tells UW-Madison News. "We often think of nature as being in these big wild spaces, but there are a lot of smaller day-to-day interactions that we don’t realize are fostering a connection to our environment."