Verizon unveiled a new carbon intensity metric last week to help the company track how efficiently it delivers data to its customers.

The telecommunications giant began testing the new metric over the last year. The metric tracks the amount of carbon dioxide emissions produced while moving a terabyte of data. Basically, the company divides its total carbon footprint by the number of terabytes of data transported across its network.

By this measure, Verizon's carbon efficiency improved 15 percent last year, compared to 2009. The company plans to replicate the improvement with another 15 percent reduction in 2011.

"We developed this metric because we are a network company, and our core measure is the amount of information we transport on our network," Verizon Chief Sustainability Officer James Gowen said in a statement Friday. "So this ratio is closely aligned with our business and will allow us to assess how we are becoming more energy efficient even as our business expands."

Companies use a variety of metrics to measure emissions, such as absolute or intensity metrics, which may be based on revenues or production. Environmentalists tend to favor absolute emissions reductions goals or disclosure since total emissions may still rise even if a company's carbon intensity is declining.

AT&T uses an intensity metric similar to Verizon's for tracking its impacts. The company measures the amount of energy used to carry a terabyte of data, rather than the carbon emissions generated. AT&T set a goal to improve its energy efficiency by 15 percent in 2009 and 2010. In 2009, the last year for which data is publicly available, AT&T reduced its energy intensity by nearly 24 percent compared to the year before.

Sprint reports its greenhouse gas emissions on an absolute basis. The company plans to reduce its absolute emissions 15 percent by 2017, relative to a 2007 baseline.

Verizon previously used an intensity metric based on revenue. The company launched a sustainability strategy last month brimming with initiatives aimed at making its fleets, products and employees greener. This includes purchasing more than 1,100 alternative fuel vehicles to its fleet and educating its employees on how to reduce energy and waste at home and work.

Image courtesy of Verizon.