The Bush administration and its corporate allies staged a celebration yesterday to mark what they called a significant commitment to reaching the goals of a voluntary program to reduce greenhouse gas emissions, which many scientists believe to be the main cause of global warming.

The event in the Energy Department's cafeteria was designed to showcase and defend the administration's voluntary approach to pollution-control programs. It brought together senior administration officials such as Energy Secretary Spencer Abraham, Agriculture Secretary Ann M. Veneman and Environmental Protection Agency Administrator Christine Todd Whitman with representatives of several industrial groups that have pledged to reduce their emissions of greenhouse gases between now and 2012.

"There is a perception by many that if environmental programs are not mandatory they're not real," Whitman said. "I'm here to tell you that these programs are very real and they're getting real results."

But officials of environmental groups scoffed at that assertion and said the administration's own projections showed that U.S. greenhouse gas emissions will continue to grow over the next 10 years even if the goal is reached. The voluntary program highlighted yesterday "is a total charade and is designed solely to provide the administration and the biggest polluting industries with political cover," said Philip E. Clapp, president of the Environmental Trust.

President Bush announced the voluntary initiative last year and set a goal of reducing the country's "greenhouse gas intensity" -- the ratio of emissions to economic output -- by 18 percent over the next decade. The administration strongly prefers such a voluntary approach instead of the mandatory caps on emissions included in the Kyoto Protocol, which has been adopted by most industrialized nations but has been rejected by the Bush administration.

Much of the dispute between the administration and environmental groups centers on how to measure progress in combating global warming. The administration's announced goal is to reduce greenhouse gas emissions relative to the size of the economy as tracked by the "greenhouse gas intensity" scale.

But environmental groups say the goal should be to reduce total emissions into the atmosphere, regardless of the economy's size. With the economy projected to grow over the next decade, they maintain that the 18 percent reduction in greenhouse gas intensity that Bush seeks translates into about a 19 percent increase in actual emissions.

"It should be measured in actual tons of pollution," said David Doniger, policy director of the Climate Center at the Natural Resources Defense Council. "The economy gets bigger and bigger but the atmosphere can't expand. Talking about it in terms of rates and the size of the economy is just sleight of hand."

Doniger, Clapp and other administration critics said only a program of mandatory caps on emissions will reduce global warming.

EPA Administrator Christine Todd Whitman, center, was among officials attending the celebration.