Government contractors would have to track their greenhouse-gas emissions or risk losing out on new contracts, under a plan released last week by the General Services Administration.

The requirement, which few companies are currently able to meet, could take effect in fiscal 2011 or 2012.

GSA prepared the 65-page document for President Obama, who issued a far-reaching executive order in October telling agencies to cut their emissions. GSA was asked to evaluate ways to measure and reduce federal contractors' emissions.

One possible action Obama suggested was requiring contractors to report their emissions and plans to reduce them. GSA's report says that goal is not feasible, at least in the short term. It recommends, instead, that federal contracting officers ask companies about their abilities to measure greenhouse-gas emissions. Their answers would be one factor in contract awards.

Few companies are now able to track their emissions, and there is no universal standard for measurement.

GSA indicates in its report that in a few years it might be possible to better examine the environmental impact at each level of the supply chain, and to force contractors to calculate and report their greenhouse-gas emissions. For now, the agency recommends simply nudging contractors in that direction.

"GSA decided that an incentive-based approach … would be most effective in providing agencies with supplier GHG emissions data," the report states.

In addition to setting up systems to track emissions, companies would be encouraged to report their emissions on a voluntary basis.

The Obama administration is reviewing GSA's report.