Bloomberg: Permits to release a ton of carbon dioxide into the air need to cost about $50 each, or three times Europe’s current price, for companies to invest in experimental technology to trap the greenhouse gas, Nicholas Stern said. At that price, projects that capture and safely bury CO2 underground can be developed to help stem emissions of the global-warming gas during the next 20 to 30 years, the London School of Economics professor said today in televised remarks at the World Future …