In large industrial experiments across the globe, factories and power plants are trying to capture the carbon dioxide that streams out of their flues in order to bury it deep underground. Researchers believe the greenhouse gas will stay put for thousands of years and therefore won't contribute to global warming, but the costs and long-term effects of the procedure are still unclear. The experiments currently underway are expected to determine whether carbon capture and storage will allow nations to continue burning fossil fuels for energy without ill effects. In France this month, the first retrofitted power plant will begin to use its new carbon capture and storage technology. The system used by the natural gas-burning power plant