Companies marketing their products and services are going green, whether they're selling cars, computers or televisions. One need look no farther than last week's Consumer Electronics Show (CES) in Las Vegas, where new products carted out invariably had a smaller carbon footprint than anything introduced a year ago. Meanwhile, products and services that aren't using enough recycled components or that hog too much energy are taking a lot of criticism.

The latest green brouhaha comes to us courtesy of a Harvard University physicist and Web juggernaut Google over the how much carbon dioxide the company's data centers are pumping into the environment each time consumers launch searches on it.

A typical search generates about seven grams of carbon dioxide, according to Alex Wissner-Gross, due to the amount of computing power required to scour the Internet for search results as quickly as possible. Wissner-Gross's research indicates that viewing a Web page generates about 0.02 grams of carbon dioxide per second, a number that jumps to about 0.2 grams of the greenhouse gas per second when viewing a Web site with complex images, animations or videos (all of which require enhanced computing power and network bandwidth to function properly), the Times of London reported yesterday.

Not so, protests Google in a blog posted today defending its enviro record and goal to become carbon neutral by using electricity derived from renewable sources only. (The company claims to have a goal of creating 50 megawatts of new renewable energy-generating capacity—via solar panels and other technologies—by 2012.) Google  insisted that Wissner-Gross's estimate of power consumed per search was "many times too high" and that the actual number is closer to 0.2 grams of carbon dioxide per search. To put things in perspective, the company notes that the average car driven for 0.6 miles (1 kilometer) produces "as many greenhouse gases as a thousand Google searches."

Data centers filled with computers (and, among other equipment, air conditioning systems required to cool them so they don't burn out) do have a significant impact on energy usage. U.S. data centers in 2006 alone consumed 61 billion kilowatt-hours—1.5 percent of the country's entire electricity consumption, according to the Green Grid, a consortium of data-hungry information technology companies (including IBM, Intel and Microsoft) that insist they're pursuing ways to build more energy-efficient data centers. Research firm Gartner, Inc., in Stamford, Conn., estimates that the IT industry generates about 2 percent of the world's global-warming emissions, about the same amount emitted by all of the world's airlines combined.

It's important to note  that Wissner-Gross is co-founder and CTO of Enernetics, a Boston-based company that charges companies to calculate their Web site's total carbon emissions and suggest measures to make it more energy efficient (or greener). The company charges businesses with fewer than 10,000 pages views a month $5 per month for its service, while sites with up to a million page views a month only pay a flat fee of $29.95 a month, reports FastCompany.com.

Wissner-Gross singled out Google to study due to its high profile and the data-driven nature of its business: Google is responsible for more than 60 percent of an estimated nearly 200 million Internet searches globally daily, reports xchange.com, a tech trade news Web site published by Virgo Publishing LLC.

If CES is any indicator, Enernetics should find a receptive market for its services. The annual consumer electronics showcase even featured a Fujitsu laptop with casing made is made from a blend of corn polymer and traditional petroleum plastic, Yahoo! Tech reported last week. Consumer electronics companies are beginning to cleanse their products of harmful PVC plastic and other hazardous chemicals, use more recycled plastic and offer product take-back programs, Greenpeace acknowledged in a report released last week.

As Sony chairman and chief executive Sir Howard Stringer noted in his CES keynote address: "Consumers are now  [weighing] recycling and renewal materials," in their purchasing decisions. Consumer electronics companies, he added, see green marketing "as an imperative in order to sell their products."