Speaking at the Rio+20 sustainability summit, the mayors of New York City and Rio de Janeiro will announce that 48 of the world’s largest cities are taking steps to cut 248 tons of greenhouse gas emissions by 2020, the equivalent of removing 44 million cars from the road for a year. New York Mayor Michael Bloomberg and Rio de Janeiro Mayor Eduardo Paes said that four-dozen cities in the C40 Cities Climate Leadership Group are reducing emissions by launching energy efficiency programs, capturing methane in landfills, installing more efficient street lighting, and other initiatives. They cite the CO2 reductions as proof that cities can make significant progress on slashing greenhouse gases even in the absence of a global agreement on cutting carbon emissions. “We’re not arguing with each other about emissions targets,” Bloomberg told reporters in a teleconference. “What we’re doing is going out and making progress.” Bloomberg and Paes said that 59 cities have committed to cut their carbon emissions by a total of 1 billion tons by 2030, equivalent to the combined greenhouse gas emissions of Canada and Mexico.