Alex Wissner-Gross wants the world to know he never said that a typical Google search leads to 7 grams of carbon dioxide being released into the atmosphere.

The Harvard University environmental fellow and founder of the carbon footprint consultancy CO2Stats has been busy in the last 48 hours, denying the claim attributed to him in a widely noticed Sunday story from The Times of London.

"It's sort of bizarre," the 27-year-old physicist said Tuesday of The Times report. His company hasn't even done specific calculations on Google's greenhouse gas emissions per search, he said – though he thinks the source of the information may be this 2007 blog post by a Sun Microsystems employee.

But while The Times and Google hash out their disagreements (Google has a blog post saying a typical search leads to only about two-tenths of a gram of CO2 being emitted), Wissner-Gross does have some suggestions for how Websites can reduce their contribution to global warming.

While there are too many variations in Web server architecture, local power production sources, and other variables to get too specific, CO2Stats calculated that the average Web search leads to 20 milligrams of CO2 per second being emitted.

"That's based on global PC averages and so on," he said. "But it's possible to do much finer-grained calculations," focusing on both where a Website's power comes from and how the Website is managed – and on the latter point, CO2Stats has some key recommendations on how to reduce wasteful practices.

"There are a few common mistakes Websites make that lead to informational inefficiencies," he said. "The first are images that are poorly or inefficiently coded," such as using the data-heavy GIF format for photos or images instead of the more compressed JPEG format.

"Another example is uncompressed Java script," he said. "If it's an enormous Java script file, network efficiency can definitely be improved by compressing it."

Beyond inefficiencies that "can't be compressed out of existence," CO2Stats offers to buy its clients renewable energy certificates, he said. Those are credits derived from producing renewable energy that can be sold or traded on government-created or voluntary markets (see Cleaning Up Greenwashing).

CO2Stats, which has taken a "limited amount" of funding from undisclosed investors, launched a prototype management service in October 2007 and its first full-scale service in August, Wissner-Gross said.

It's a good time to be in the business of greening up information technology. The subject has taken center stage with electronics and IT companies promoting more energy-efficient and environmentally friendly products and services (see CES Plugs Green Technology and Venture Power in Japan: Green Electronics).

It has also led to no small amount of sniping between companies disputing each others' green claims (see Dell to Apple: Our Laptop Is Greener Than Your Laptop), as well as some confusion over just how to measure the IT industry's contribution to environmental problems, as with the Google citation Wissner-Gross denies making.

Google has been taking steps to reduce energy use in its data centers and is a member of the Climate Savers Computing Initiative, a group calling for improved energy efficiency in the IT sector. The company also is a financial backer and proponent of developing renewable energy and energy efficiency (see Google Proposes $4.4T U.S. Energy Plan and Google and GE Gang Up for Green Energy).

Despite the fact that Wissner-Gross considers being misquoted by The Times as an unfair knock against Google, all the attention is part of a groundswell in public perception, he said.

"Probably for the first time, the mainstream public is starting to think about green information technology," he said.

Given that a 2007 report from Gartner estimated that the greenhouse-gas emissions impact of the information and communication technology sectors was greater than that of the global aviation industry, "I think that's really remarkable," he said.