Urban 'Green' Spaces May Contribute to Global Warming

http://www.sciencedaily.com/releases/2010/01/100119133515.htm

ScienceDaily (Jan. 22, 2010) — 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.

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"It's impossible for these lawns to be net greenhouse gas sinks because too much fuel is used to maintain them," Townsend-Small concluded.