This week Dell announced that it is the first major computer manufacturer to neutralize its carbon impact. It launched a new program called "Plant a Forest for Me" that lets organizations join together to plant millions of trees in order to offset their carbon consumption. And CEO Michael Dell challenged his peer companies to up the ante.

But Ian Brown, senior analyst at Ovum, a consulting firm with clients such as Hewlett Packard, IMB, Sun Microsystems and Microsoft, critiques Dell's challenge by calling it a marketing ploy.

"While we're sure Dell is very sincere in his belief that carbon offsetting is needed to slow down climate change, this is all about marketing," said Brown. "Dell is engaged in a battle with HP, IBM, Sun and others to prove how green it is."

He said he'd prefer Dell to offer "practical assistance for customers on how to reduce energy wastage and improve resource efficiency in their data centers. Data centers are notoriously inefficient in their use of resources, particularly computer resources – most have too many servers running too few workloads.

"Dell may be ahead on the offsetting, but it needs to catch up on services and its ability to help customers reuse and share resources, reduce costs and maybe, just maybe, help the planet a little too."

But might those words seem a little funny, coming from someone who consults Dell's competing computer manufacturers?

Nonetheless, the some other computer companies are doing their part as well. And whether the changes are for marketing or reducing energy, they're good steps.

Earlier this week, Sun Microsystems released OpenEco.org, an open-source software program that allows companies to track their carbon emissions. In the past five years Sun reduced its energy output by 20 percent and last June, reduced the energy used in one of its data centers by 93 percent by switching out older models for its new Niagara servers.

Intel developed an online project Lesswatts.org, which hosts a group of software developers working to build Linux operating system upgrades that will more efficiently use server hardware and save energy.

And HP joined Bell Micro to launch an initiative called "Going Green," a green package for Bell's resellers that will focus on datacenters and offer a datacenter assessment service.