In a presentation before an audience of Silicon Valley technology industry and government officials, U.S. Senator Barbara Boxer Monday criticized President George Bush for arguing that the U.S. can't regulate carbon emissions because it would hurt the U.S. economy when fast-growing economies like those of China and India do not control pollution.

"Since when does any [U.S.] president look to China for environmental leadership?" asked Boxer, a Democrat from California. "We can't wait for China. We have to be the moral leaders on this."

Boxer said she plans to call U.S. Environmental Protection Agency (EPA) officials before a congressional committee to explain how the agency is going to regulate greenhouse gas emissions linked to global climate change. Her move is in response to a U.S. Supreme Court ruling on April 2 that the EPA has the authority to regulate carbon emissions. The Bush administration had argued that it does not.

Boxer spoke at an energy conservation event sponsored by Advanced Micro Devices Inc. and the Silicon Valley Leadership Group at AMD headquarters. AMD, like other IT vendors, is focusing new attention on energy-efficiency in product design and how they operate their business.

Along with Dell Inc., Sun Microsystems Inc., Hewlett-Packard Co., IBM Corp. and others, AMD is a member of the Green Grid alliance, an industry group formed to share technical expertise and best practices to make more energy-efficient computers, servers and other equipment.

AMD is building an 870,000-square foot office complex in Texas to house 2,500 employees, which will be powered completely by renewable energy sources, said Larry Vertal, senior strategist of enterprise communications in AMD's microprocessor segment.

AMD is committed to reducing its energy consumption by 30 percent in 2007, compared to 2002, and to reduce greenhouse gas emissions by 40 percent, he said.

Carbon emissions are generated from burning carbon-based fuels such as oil in cars, planes, manufacturing plants or homes. The emissions, also called greenhouse gases, collect in the upper atmosphere and, scientists say, lead to a gradual increase in average global temperatures.