Green has a Price
Introduction
Green, healthy lawns are adding to the problem of climate change. A green space in a concrete, urban jungle has aesthetic values. It also falls in step with the theory of miniature carbon sinks. But in reality maintening the lawn costs more than what it can offset. Southern California researchers say CO2 emissions from fertilizer production, mowing and other lawn practices are four times more than the amount stored by the grasses. Fertilizers also help the soils release nitrous oxides, another greenhouse gas.
Source
Down To Earth, February 2010