Dell, the computer maker said will make its operations carbon-neutral by 2008, a year earlier than it previously promised.

Dell said it would achieve the goal through a variety of methods, including buying so-called carbon offsets, replacing incandescent light bulbs with fluorescent and requiring parts suppliers to list information on their environmental policies.

Among the gases that contribute to global warming, carbon — generated in the United States mainly in energy production and transportation — is the most voluminous.

For Dell, going carbon-neutral means the company will find ways to offset every pound of greenhouse gas generated in the production, transportation and sales of its computers. Possible methods include using renewable energy sources such as wind, managing electricity use more efficiently and planting trees, which gradually absorb carbon dioxide as they mature.

Dane Parker, the director of Dell’s global environmental health and safety programs, said the company has spent US$5 million so far on energy-saving efforts. He acknowledged that buying offsets from other entities that have made extra cuts in their carbon production will be Dell’s main route to carbon neutrality in the short term.

“Our priority is to minimize total (energy) consumption,” he said. But “offsets are what we will do as a last resort in the most responsible way we can.”

Parker said specific changes Dell has already taken include turning off computer systems at night and replacing incandescent light bulbs with more efficient fluorescent designs. Such measures have cut Dell’s electricity bill by US$1.8 million in the past year, company officials said. It was unclear how big a percentage of its total bill that was.

Robin Schneider, executive director of the Texas Campaign for the Environment, said she was encouraged by Dell’s news but would like to see data on how many tons of carbon Dell produces and how much it plans to remove.

She noted that Dell has not addressed its production of other greenhouse gasses such as methane.

“I think we do need to see a very clear before-and-after so that it’s not just a press release that gets good headlines,” she said.

Dell should be lauded for taking the initiative, said Iza Kruszewska of Greenpeace International. But the company isn’t addressing the full impact of a computer’s life cycle from raw material to outdated e-waste.

“We have to realize that Dell is talking about carbon neutrality only in its operations,” she said. “But are you going to go back to the mining of the minerals?”

There’s no way to verify a company’s carbon neutral claims in the United States, because the federal government doesn’t track companies’ green house gas emissions, she said.

Company founder and CEO Michael Dell said in an interview that the company’s environmental policies were “the right thing to do.”

“When you think about our industry, we produce 260 million computers a year,” he said Tuesday. “There’s a responsibility that comes with that.”

The Round Rock, Texas, company’s greener push comes amid a turnaround attempt by Dell upon his return to the helm. The company has lost market share to Hewlett-Packard Co., and continues to deal with the fallout of a federal accounting probe.

The company is not alone in trying to do better by the environment.

HP spokeswoman Kelly Newton said her company has long been a leader in reducing overall emissions and was named best in class this week by the Carbon Disclosure Project, an international nonprofit to which companies submit reports on greenhouse gas emissions and other environmental issues.

“We commend others in our industry who are now joining in these efforts,” Newton said.

Greenpeace International placed Dell fourth in a ranking this year of the environmental friendliness of 14 global technology companies. It landed behind Lenovo Group Ltd., Nokia Corp. and Sony Ericsson Mobile Communications. Apple Inc. has disputed its last-place showing; Hewlett Packard finished in eighth place.

John Davies, an environment and sustainability analyst with AMR Research in Boston, said this rivalry shows how important the environment has become for the computer industry.

“You have IBM Corp., HP and Dell all battling it out on this environmental field, and that’s very different than, ‘My processor has a clock speed faster than yours,'” he said.

Dell also announced Wednesday that it was expanding its “Plant a Tree for Me” program, in which customers can choose to have US$2 of a laptop purchase or US$6 of a desktop purchase go toward funds to plant trees around the world. Other companies also will be able to purchase trees to offset their carbon impact, Dell spokesman Bryant Hilton said.

The company also is partnering with Advanced Micro Devices Inc., Ask.com, Salesforce.com, WellPoint and other businesses to share information about environmental practices and establish more reforestation projects.