Energy Policy, by Evan Mills, PhD and Staff Scientist at Lawrence Berkeley National Laboratory, 2012.
http://evan-mills.com/energy-associates/Indoor_files/cannabis-carbon-footprint.pdf

We usually only post very current reports and articles, but this one is so relevant and a new topic of interest for many, that we decided to go ahead and list it.

"This article presents a model of the modern-day production process—based on public sources and equipment vendor data—and provides national scoping estimates of the energy use, costs, and greenhouse-gas emissions associated with this activity in the United States."