https://phys.org/news/2018-05-carbon-footprints-cities.html > The paper's lead author, Daniel Moran, says he was surprised at just how concentrated carbon footprints are. > "The top 100 highest-footprint cities worldwide drive roughly 20% of the global carbon footprint," Moran said. "This means concerted action by a small number of local mayors and governments can significantly reduce national total carbon footprints."