Backyards May Play Role in Climate Change More than 5 billion tons of carbon dioxide enter the U.S. atmosphere each year. Scientists in Baltimore are studying whether backyards help absorb carbon dioxide, and by so doing, slow the pace of climate change.
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Backyards May Play Role in Climate Change

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Backyards May Play Role in Climate Change

Backyards May Play Role in Climate Change

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This ALL THINGS CONSIDERED from NPR News. I'm Debbie Elliott.

On this date in 1970, environmental activists raised the consciousness of the nation with an event called Earth Day. Twenty million Americans turned out. The voice of organizer Denis Hayes.

Mr. DENIS HAYES (Environmental Activist): We are systematically destroying our land, our streams, and our seas. We foul our air, deaden our senses, and pollute our bodies. That's what America has become. That's what we have to challenge.

ELLIOTT: Thirty-six years later, American tailpipes and smokestacks are spewing more than five billion tons of carbon dioxide into the atmosphere. About half of that stays in the air, where it contributes to global warming. The rest is soaked up by oceans, plants and soil. Scientists studying neighborhoods in Baltimore are trying to figure out whether our backyards are also helping absorb some of this gas, and by doing so, slowing the pace of climate change.

NPR's Richard Harris reports.


Most ecologists gravitate toward forests, or leafy glades, or savannahs, or other places where nature abounds.

Ms. ELLEN SCHMITT (Biologist, Baltimore Ecosystems Study): Forty-three and 39.

HARRIS: But on a recent morning, two biologists carrying clipboard and camera confer earnestly with one another while prowling a neighborhood of '70s vintage, single-story brick homes, in suburban Baltimore.

Ms. SCHMITT: This yard here, do you want to try to put it where the sun's hitting in the front yard?

Ms. JENNIFER JENKINS (Biologist, Baltimore Ecosystems Study): I think one may be close to the turf plot.

HARRIS: An elderly woman, carrying bags of groceries couldn't resist crossing the street to see why they were examining someone's yard. Can I be nosy, she asked as she approached?

Ms. SCHMITT: Sure.

(Soundbite of laughter)

Ms. MARY TOPPER(ph) (Resident, Baltimore): What are you all doing?

Ms. SCHMITT: We're with Baltimore Ecosystems Study. And we're doing a residential carbon project and the (unintelligible) signed up to participate in the project. So they volunteered this property to help the project.

Ms. TOPPER: I just saw you down below.

HARRIS: Ellen Schmitt tells Mary Topper that four families on this street have volunteered to turn a small patch of their lawn into ecological study plots. She will measure how much carbon dioxide the grass takes from the air as it grows.

Ms. SCHMITT: But you'll definitely see myself and maybe a couple other people like very week in the summer out here. So we'll stop and say hi.

Ms. TOPPER: Oh, good. I'm going to get to know y'all.

(Soundbite of laughter)

Ms. SCHMITT: Okay.

HARRIS: As the project ramps up, it will no doubt draw more curious onlookers. In order to figure out how much carbon is being taken up by the plants and the soils in these yards, Ellen Schmitt will be taking three-foot deep core samples of soil. She'll measure the girth of trees and shrubs, and even vacuum up grass clippings.

Ms. JENKINS: This side yard is not going to work. It's all dirt.

(Soundbite of laughter)

Ms. JENKINS: So it looks like this probably gets a lot of shade, too. I mean, there's no grass. This is a...

HARRIS: Jen Jenkins, from the University of Vermont, is in charge of the project. She says working in residential neighborhoods isn't as romantic as tromping out into the forest. But she feels like a pioneer, at least scientifically.

Ms. JENKINS: People know a lot about forests. They know a lot about agricultural systems. They know a lot about grasslands. But we have this large and growing area of residential land that people just don't know very much about.

HARRIS: And it's huge. Jenkins figures that residential areas in the U.S., altogether, spread across land three times the size of Ohio. Backyards are also where humans connect with the earth.

Ms. JENKINS: This is where people live. If you invite somebody out onto their lawn to tell you about their lawn, they know about their lawn. And they're going to give you, you know, this patch tends to grow more quickly than this patch in the summer. And this patch is where I fertilize. And this patch is, you know, where my dog likes to lay down. And this is where my kids play kickball. It's really just fascinating how people are connected to their land in that kind of a way. So yeah, it's not that romantic. But it's important.

HARRIS: Her big challenge at the moment is figuring out how to stake out small samples that will be truly representative of the whole ecosystem they're studying. And it turns out that man's best friend is proving to be a big challenge.

Ms. JENKINS: The issue with this particular lawn in the back is, you can see, there's little clumps of grass. And my guess is that this is where the dog goes.

HARRIS: Adding a little nitrogen.

Ms. JENKINS: Maybe a lot of nitrogen. So that would be sort of a nitrogen hotspot.

HARRIS: Nitrogen is fertilizer. So this grass will grow especially well. So this lawn might be especially good at taking carbon out of the air and helping in a tiny way to slow the rate of climate change. So she wonders, is a dog-fertilized lawn truly typical of Baltimore backyards? Or if she samples this patch of grass will she overestimate how much carbon a typical lawn takes up?

(Soundbite of a closing door)

HARRIS: As the scientists move yard to yard, and neighborhood to neighborhood, this proves to be a bigger issue than she had imagined.

(Soundbite of clapping)

Unidentified Man #1: Come on. Would you like me to lock him up?

HARRIS: At one home, three frisky Golden Retrievers bound out to greet them. At another, a husky stands sentinel at the top of the driveway. But the most impressive encounter comes at a neatly landscaped home in the Cockeysville area.

(Soundbite of a dog barking)

HARRIS: Kit Wolfe(ph) answers the door and holds back two huge and elegant beasts, English Mastiffs.

Ms. KIT WOLFE: I'll be out in two seconds.

Mr. JENKINS: Okay.

HARRIS: We head around to the back of the house so the scientists can scout a location for their study plot. Ellen Schmitt has already thought about where to sample in this yard to avoid too much of the doggy effect.

Ms. SCHMITT: You'll see when you walk around a lot of droppings. And the dogs do come in here during the summer. So even though it's within the fence, this isn't necessarily a safe area.

Ms. JENKINS: It's a pretty significant input.

HARRIS: Much more so than animals in the forest, it sounds like. In some ways, animals in residential areas may have a more profound impact.

Ms. JENKINS: They'd have a bigger impact because they're concentrated in a smaller area.

HARRIS: So dogs are turning out to be a pretty big issue for you.

Ms. JENKINS: It turns out, actually, that they are.

(Soundbite of laughter)

Ms. JENKINS: As we've learned, yeah.

HARRIS: I could already see title to one of your papers.

(Soundbite of laughter)

HARRIS: Dogs and Global Warming: The Untold Story.

Ms. JENKINS: The untold -- right. Yeah. We may be onto something here.

HARRIS: The animals in question come frolicking down the yard behind the scientists. And their owner, Kit Wolfe, follows behind like a proud parent.

Ms. WOLFE: This is Chauncy and the big one is George. George weighs a little over 200 pounds. And he just was at the Westminster Kennel Club Show. Yes. He did not win, but he was there, competing.

HARRIS: The dogs slobber. And yes, find other ways to fertilize the lawn, as the humans scope out the suburban landscape. Kit Wolfe says she is happy to help out the scientists as they go about figuring out the ebb and flow of carbon in her backyard.

Ms. WOLFE: I thought it was really kind of simple since they were just going to, you know, be dealing with little plots of grass on our lawn. And I thought we have enough lawn that we could, you know, agree to do this.

HARRIS: Ultimately, this has to do with climate change, too. Is that an issue you think about?

Ms. WOLFE: Well, rate climate change like the whole world? Like global warming, stuff like that, is that a big issue? Honestly? No.

(Soundbite of laughter)

Ms. WOLFE: That's not something I worry about. But maybe, you know, I'll find out more about it. And maybe I should start worrying about it.

HARRIS: If Kit Wolfe someday decides that she does want to do something about climate change, Jen Jenkins says she could star with her backyard. She could consider planting more trees, since they soak up carbon dioxide and hold it for decades. But that's still small potatoes.

Ms. JENKINS: Probably, if you wanted to make a difference with respect to climate change, you would be thinking about things that would maybe give your more bang for your effort; maybe using a hand mower, instead of a gasoline mower.

HARRIS: Jenkins doesn't know how much backyard greenery will help in slowing climate change. That's what her study may reveal. But realistically, we can't expect it to soak up the many tons of carbon dioxide that we each put into the air every year.

Richard Harris, NPR News.

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