The United States can reduce greenhouse gas emissions by 80 percent by 2050, using existing or near-commercial technologies, according to researchers with the Deep Decarbonization Pathways Project. The study analyzed scenarios with four types of decarbonized electricity: renewable energy, nuclear energy, fossil fuel with carbon capture and storage, and a mixed case. The scenarios achieved reductions of 83 percent below 2005 levels and 80 percent below 1990 levels, according to the study, which was released ahead of next month’s climate talks in Lima, Peru, and negotiations in Paris in December 2015. The energy efficiency of buildings, transportation, and industry would need to increase through the use of smart materials and energy-efficient designs, and vehicles will need to be fueled with electricity generated from wind, solar, or nuclear, as opposed to coal, the researchers said. They project the net costs would be on the order of 1 percent of gross domestic product per year. The 80-percent reduction by 2050 is a long-standing goal of the Obama administration, in line with global commitments to limit warming to less than 2 degrees C.