Now that venture capitalists are so taken with green tech, perhaps they can push some VC dollars toward the development of a greener data center. Because according to consultancy McKinsey, data centers are fast becoming the Superfund sites of the tech industry. McKinsey found that data centers are responsible for 0.3% of the world’s carbon-dioxide emissions. That’s about half of what the airline industry generates–and by 2020 it will surpass it.

“The more you look, the more you find that the entirety of the IT stack, from the CPU up, is very inefficient,” said William Forrest, the associate principal for IT at McKinsey. “Data centers are becoming a major business issue. We think it’s going to become a regulatory concern that will drive scrutiny not just in (corporate) boardrooms but with regulators as well.”

So what’s to be done? McKinsey proposes that corporations at least double the efficiency of their data centers by 2012 and adopt its Corporate Average Data Efficiency metric, a sort of fuel efficiency standard for IT. Said Forrest, “It’s miles per gallon for data centers.“