The Internet stands to revolutionize the relationship between economic growth and the environment, according to the report from the Center for Energy & Climate Solutions, a non-profit organization outside Washington, D.C., that helps companies and public institutions reduce their greenhouse gas emissions.

The authors of the report, entitled "The Internet Economy and Global Warming: A Scenario of the Impact of E-Commerce on Energy and the Environment," believe the revolution is already manifesting itself as a sudden shift in the country''s energy diet. While the economy grew more than 9 percent in 1997 and 1998, energy demand stayed almost flat in spite of very low energy prices. Such gains mark a major departure from recent historical patterns.

"The Internet economy could allow a very different type of growth than we have seen in the past," said Joseph Romm, lead author and executive director of the center. "It means there is also a new energy economy that will have profound impacts on not only on the environment, but also economic forecasting." Romm previously headed the $1 billion energy efficiency and renewables program at the U.S. Department of Energy.

For example, the report says the ratio of energy consumed per book sold in traditional bookstores versus online retailer Amazon.com is 16 to 1. Internet shopping uses less energy to get a package to your house. Shipping 10 pounds of packages by overnight air -- the most energy-intensive delivery mode -- uses 40 percent less fuel than driving round-trip to the mall. Ground shipping by truck uses just one-tenth the energy of driving yourself.

By 2007, the Internet could avoid the need for some 5 percent of total commercial building space. This includes up to 1.5 billion square feet of retail space, 1 billion square feet of warehouses, and as much as 2 billion square feet of commercial office space, the equivalent of almost 450 Sears Towers, says the report.

The resulting energy savings from operations and maintenance alone total 53 billion kilowatt hours per year -- the output of more than 21 average power plants -- and 67 billion cubic feet of natural gas, preventing the release of 35 million metric tons of greenhouse gases into the atmosphere.

Avoided construction of all those buildings saves the equivalent of 10 more power plants worth of energy, and another 40 million metric tons of greenhouse pollution.

The Internet could save 2.7 million tons of paper every year by 2003, despite increased use of office paper. The resulting annual cut in global warming pollution equals some 10 million tons of carbon dioxide. Both figures could double by 2008, says the report.

Each minute spent driving to the mall uses more than 10 times the energy of a minute spent shopping online. Online shopping avoids car trips and reduces congestion. Already, nearly 40 percent of people with Internet access say they go to the store or the mall less often.

"The Internet can turn buildings into Web sites, and replace warehouses with supply chain software," said Romm. "It can turn paper and CDs into electrons, and replace trucks with fiber optic cable. That means significant energy savings."

The authors found that the Internet itself is not a major energy user, largely because it draws heavily on existing communications and computing infrastructure. They report the average PC and monitor uses just 150 watts of power. Today''s new computers are more than twice as efficient as those they are replacing. As for the fast-growing information technology sector in general, the report concludes it is far less energy-intensive than most conventional industries.

The Center for Energy and Climate Solutions is a division of the Global Environment & Technology Foundation