Featured Research

from universities, journals, and other organizations

Urban 'green' spaces may contribute to global warming

Date:
January 22, 2010
Source:
University of California - Irvine
Summary:
Dispelling the notion that urban "green" spaces help counteract greenhouse gas emissions, new research has found -- in Southern California at least -- that total emissions might be lower if lawns did not exist.

Freshly mowed grass. Turfgrass lawns help remove carbon dioxide from the atmosphere through photosynthesis and store it as organic carbon in soil, making them important "carbon sinks." However, greenhouse gas emissions from fertilizer production, mowing, leaf blowing and other lawn management practices are four times greater than the amount of carbon stored by ornamental grass in parks.
Credit: iStockphoto/Nicholas Campbell

Dispelling the notion that urban "green" spaces help counteract greenhouse gas emissions, new research has found -- in Southern California at least -- that total emissions might be lower if lawns did not exist.

Turfgrass lawns help remove carbon dioxide from the atmosphere through photosynthesis and store it as organic carbon in soil, making them important "carbon sinks." However, greenhouse gas emissions from fertilizer production, mowing, leaf blowing and other lawn management practices are similar to or greater than the amount of carbon stored by ornamental grass in parks, a UC Irvine study shows. These emissions include nitrous oxide released from soil after fertilization. Nitrous oxide is a greenhouse gas that's 300 times more powerful than carbon dioxide, the Earth's most problematic climate warmer.

"Lawns look great -- they're nice and green and healthy, and they're photosynthesizing a lot of organic carbon. But the carbon-storing benefits of lawns can be counteracted by greenhouse gas emissions," said Amy Townsend-Small, Earth system science postdoctoral researcher and lead author of the study, forthcoming in the journal Geophysical Research Letters.

The research results are important to greenhouse gas legislation being negotiated. "We need this kind of carbon accounting to help reduce global warming," Townsend-Small said. "The current trend is to count the carbon sinks and forget about the greenhouse gas emissions, but it clearly isn't enough."

Turfgrass is increasingly widespread in urban areas and covers 1.9 percent of land in the continental U.S., making it the most common irrigated crop.

In the study, Townsend-Small and colleague Claudia Czimczik analyzed grass in four parks near Irvine, Calif. Each park contained two types of turf: ornamental lawns (picnic areas) that are largely undisturbed, and athletic fields (soccer and baseball) that are trampled and replanted and aerated frequently.

The researchers evaluated soil samples over time to ascertain carbon storage, or sequestration, and they determined nitrous oxide emissions by sampling air above the turf. Then they calculated carbon dioxide emissions resulting from fuel consumption, irrigation and fertilizer production using information about lawn upkeep from park officials and contractors.

The study showed that nitrous oxide emissions from lawns were comparable to those found in agricultural farms, which are among the largest emitters of nitrous oxide globally.

In ornamental lawns, nitrous oxide emissions from fertilization offset just 10 percent to 30 percent of carbon sequestration. But fossil fuel consumption for management, the researchers calculated, released almost as much or more carbon dioxide than the plots could take up, depending on management intensity. Athletic fields fared even worse, because -- due to soil disruption by tilling and resodding -- they didn't trap nearly as much carbon as ornamental grass but required the same emissions-producing care.

"It's unlikely for these lawns to act as net greenhouse gas sinks because too much energy is used to maintain them," Townsend-Small concluded.

Previous studies have documented lawns storing carbon, but this research was the first to compare carbon sequestration to nitrous oxide and carbon dioxide emissions from lawn grooming practices.

The UCI study was supported by the Kearney Foundation of Soil Science and the U.S. Department of Agriculture.

Editor's Note: The original version of the news release, distributed Jan. 19, has been updated here to reflect the correction of a spreadsheet error in the scientific paper regarding carbon dioxide emissions during lawn maintenance.


Story Source:

The above story is based on materials provided by University of California - Irvine. Note: Materials may be edited for content and length.


Journal References:

  1. Amy Townsend-Small, Claudia I. Czimczik. Carbon sequestration and greenhouse gas emissions in urban turf. Geophysical Research Letters, 2010; 37 (2): L02707 DOI: 10.1029/2009GL041675
  2. Amy Townsend-Small, Claudia I. Czimczik. Correction to 'Carbon sequestration and greenhouse gas emissions in urban turf'. Geophysical Research Letters, 2010; 37 (6): L06707 DOI: 10.1029/2010GL042735

Cite This Page:

University of California - Irvine. "Urban 'green' spaces may contribute to global warming." ScienceDaily. ScienceDaily, 22 January 2010. <www.sciencedaily.com/releases/2010/01/100119133515.htm>.
University of California - Irvine. (2010, January 22). Urban 'green' spaces may contribute to global warming. ScienceDaily. Retrieved July 25, 2014 from www.sciencedaily.com/releases/2010/01/100119133515.htm
University of California - Irvine. "Urban 'green' spaces may contribute to global warming." ScienceDaily. www.sciencedaily.com/releases/2010/01/100119133515.htm (accessed July 25, 2014).

Share This




More Earth & Climate News

Friday, July 25, 2014

Featured Research

from universities, journals, and other organizations


Featured Videos

from AP, Reuters, AFP, and other news services

Goma Cheese Brings Whiff of New Hope to DRC

Goma Cheese Brings Whiff of New Hope to DRC

Reuters - Business Video Online (July 24, 2014) The eastern region of the Democratic Republic of Congo, mainly known for conflict and instability, is an unlikely place for the production of fine cheese. But a farm in the village of Masisi, in North Kivu is slowly transforming perceptions of the area. Known simply as Goma cheese, the Congolese version of Dutch gouda has gained popularity through out the region. Ciara Sutton reports. Video provided by Reuters
Powered by NewsLook.com
Bill Gates: Health, Agriculture Key to Africa's Development

Bill Gates: Health, Agriculture Key to Africa's Development

AFP (July 24, 2014) Health and agriculture development are key if African countries are to overcome poverty and grow, US software billionaire Bill Gates said Thursday, as he received an honourary degree in Ethiopia. Duration: 00:36 Video provided by AFP
Powered by NewsLook.com
Higgins Breaks Record at Mt. Washington

Higgins Breaks Record at Mt. Washington

Driving Sports (July 24, 2014) Subaru Rally Team USA drivers David Higgins and Travis Pastrana face off against a global contingent of racers at the annual Mt. Washington Hillclimb in New Hampshire. Includes exclusive in-car footage from Higgins' record attempt. Video provided by Driving Sports
Powered by NewsLook.com
Storm Kills Three, Injures 20 at Virginia Campground

Storm Kills Three, Injures 20 at Virginia Campground

Reuters - US Online Video (July 24, 2014) A likely tornado tears through an eastern Virginia campground, killing three and injuring at least 20. Linda So reports. Video provided by Reuters
Powered by NewsLook.com

Search ScienceDaily

Number of stories in archives: 140,361

Find with keyword(s):
Enter a keyword or phrase to search ScienceDaily for related topics and research stories.

Save/Print:
Share:

Breaking News:
from the past week

In Other News

... from NewsDaily.com

Science News

    Health News

      Environment News

        Technology News



          Save/Print:
          Share:

          Free Subscriptions


          Get the latest science news with ScienceDaily's free email newsletters, updated daily and weekly. Or view hourly updated newsfeeds in your RSS reader:

          Get Social & Mobile


          Keep up to date with the latest news from ScienceDaily via social networks and mobile apps:

          Have Feedback?


          Tell us what you think of ScienceDaily -- we welcome both positive and negative comments. Have any problems using the site? Questions?
          Mobile: iPhone Android Web
          Follow: Facebook Twitter Google+
          Subscribe: RSS Feeds Email Newsletters
          Latest Headlines Health & Medicine Mind & Brain Space & Time Matter & Energy Computers & Math Plants & Animals Earth & Climate Fossils & Ruins