When it comes to global warming, most people worry about power plants. Claire White thinks about another kind of plant — those that make cement. "Cement production and cement powder are a major component of greenhouse gas emissions," said White, an assistant professor of civil and environmental engineering and the Andlinger Center for Energy and the Environment at Princeton University. "It accounts for between 5 and 8 percent of human-made carbon dioxide."

Along with co-researchers from across the University, White is exploring ways to manufacture cement with a much lower contribution to global warming. Some of these cement substitutes completely eliminate the need to burn limestone at high temperature, a critical step in standard cement production that accounts for much of the CO2 emissions. By using waste components such as slag from steel manufacturing instead of cement powder, manufacturers can cut greenhouse emissions by 80 to 90 percent, White said.