The world could be powered 100 percent by wind, water and sunlight within the next 20 to 40 years, argued Stanford University's Mark Jacobson at the Feb. 4 Ezra Round Table discussion in 258 Rhodes Hall.

Jacobson, a professor of civil and environmental engineering and director of the Atmosphere/Energy Program at Stanford, said his mathematical models show that solar-, wind- and water-powered systems can realistically provide adequate energy to the entire world.

Technologies that cut carbon dioxide emissions, air pollutants and water consumption of standard power plants are not only more environmentally friendly, but also would reduce air pollution, thereby saving human lives. Jacobson argued that when weighing the costs and benefits of new clean energy technologies, such "externality costs" as rising health insurance premiums "need to be accounted for because these are real costs people are paying through insurance and taxation."

Jacobson spoke primarily about converting all U.S. vehicles to run on electric battery power, using solar, wind and water as energy sources. "There's at least five times more wind in extractable locations ... and 20 times more solar than you would need to power the world," he said. These energy sources could be harnessed to provide enough power to satisfy our current and future energy demands, while helping the United States achieve energy independence.

While corn and cellulose-derived ethanol have been on the radar for several years as potential energy sources, Jacobson argued that solar, wind and water power are more environmentally friendly.

"If you account for land use change, the high estimate is that you would double your carbon dioxide emissions," Jacobson said, explaining how using corn for fuel would affect global corn prices, which could lead to increased deforestation rates in countries that could create more farmland to compete with the higher corn prices.

Nuclear energy, which has long been touted as a clean energy technology, also has its flaws. "If we look historically, there is a link between the spread of nuclear energy facilities and the spread of nuclear weapons," Jacobson said.

Even if wind-, water- and solar-powered electricity grids aren't perfected yet, converting now to battery electric-powered vehicles would be beneficial, Jacobson said, explaining that such vehicles emit 30 percent less carbon dioxide than gas-powered vehicles.

The seminar was sponsored by Cornell's Systems Engineering Program.

Graduate student Kate Engler is a student writer intern for the Cornell Chronicle.