Urban 'green' spaces may contribute to global warming

Science Daily: Dispelling the notion that urban "green" spaces help counteract greenhouse gas emissions, new research has found -- in Southern California at least -- that total emissions would 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 four times 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 are counteracted by fuel consumption," 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."…

Lawn flamingos in El Sobrante, California, shot by Southgeist, Wikimedia Commons, under the Creative Commons Attribution 2.5 Generic license.