Keen to remind us of how our actions contribute to global climate change, Google's Green Energy Czar Bill Weihl published a blog post this week voicing approval for innovative efforts to address energy consumption.

However, Weihl came not to praise the parsimonious use of power but to bury fluffy science. Specifically, he took issue on Thursday with the claim that "Blackle," a black background version of the Google, is more energy efficient than the stark white background version of Google. The basis for that claim is a 2002 study that found black monitor screens require less power than white screens.

Blackle was created by Heap Media, an Australian online services company. "We believe that there is value in the concept because even if the energy savings are small, they all add up," the firm explains on the Blackle Web site. "Secondly we feel that seeing Blackle every time we load our Web browser reminds us that we need to keep taking small steps to save energy."

Certainly, Blackle has value as a reminder, not unlike the even more energy efficient Post-it note. But its value as an energy conservation tool is less clear. As Weihl sees it, Blackle may do more harm than good.

"We applaud the spirit of the idea," Weihl said, "but our own analysis as well as that of others shows that making the Google homepage black will not reduce energy consumption. To the contrary, on flat-panel monitors (already estimated to be 75% of the market), displaying black may actually increase energy usage."

It may not be that simple, however. As Australian tech journalist Darren Yates explains on his Techlogg blog, "Blackle makes next to no difference, on average, with LCD monitors." But Blackle did deliver small energy savings with 24-inch and larger LCDs and with CRT monitors.

Yates concludes that those who are serious about saving energy should shut their computers down in the evening and let the screen go dark rather than use a screen saver.

Yates' research makes no mention of the amount of energy that would be saved were Microsoft to quit shipping Windows games like Minesweeper.