Greenhouse gas emissions aren't necessarily the first thing that comes to mind in a typical data center. With its almost sterile climate-controlled interiors and the absence of chemical discharges or smoke, the data center might seem at first glance to be perfectly eco-friendly. Still, it is becoming one of the fastest-growing contributor to global emissions, which are projected to rise fivefold between 2002 and 2020, according to the McKinsey analysis. The electricity to feed the IT demand, of course, comes from generating stations that produce varying levels of emissions, depending on their fuel type, making IT a significant contributor to global warming, albeit indirectly.

The tools for assessing enterprise-level green practices have evolved from do-it yourself Excel spreadsheets to elaborate carbon accounting software suites available on a subscription basis. By first determining a baseline, organizations can set clear goals for adopting greener IT practices.

Software can allow entire organizations, not just IT shops, to understand the sources of their emissions, to prepare reports for registries maintained by the U.S. Environmental Protection Agency (EPA) and other agencies, and to view performance "dashboards" of emissions across the enterprise. Software-makers envision a time when companies can use such tools to aid with compliance or even to make money through proposed carbon exchange markets.