In June 2006 Toronto's Upper Canada College (UCC) decided to offset the greenhouse gas (GHG) emissions related to the life cycle of the new artificial turf field installed on their campus. Together with the Athena Institute for Sustainable Materials they did an LCA study looking at the impacts of the turf from raw material acquisition through to manufacturing, transportation, use and maintenance, and end-of-life disposal. They also compared the artificial turf to a natural turf system (the baseline). They compared the baseline and the project using a functional unit of a 9000 m2 field over a 10-year period according to ISO 14044:2006 standards.
A larger version of this table can be found on page 8 of this pdf
Total greenhouse gas emissions for the natural turf were actually negative, coming in at -16.9 tons of CO2 thanks to natural grass carbon sequestration, while for the artificial turf system the total CO2 emissions were 55.6 tons. However the report justifies their artificial choice stating that the artificial turf is, "easier on the players' joints and is designed to reduce sports-related injuries. Additionally, because the artificial surface won't freeze when temperatures drop, the sports season for both Upper School and Prep students can extend further into the year." To achieve their carbon neutral synthetic turf installation, the study estimates that UCC needs to plant 1861 trees. That's a lot of trees for one private school! Even though they didn't choose the natural option, at least they're going to compensate for their decision. It looks like they're going to get their carbon neutral field by planting those trees and reusing the soil that was excavated. Go UCC! Look at the full report here.