Cities in Asia and the United States emit the most heat-trapping gas that feeds climate change, and Shanghai is the most polluting. That's according to new data that combines observations and artificial intelligence to quantify emissions around the world. Seven states or provinces spew more than 1 billion metric tons of greenhouse gases. All are in China except for the U.S. state of Texas, which ranked sixth. The data comes from an organization co-founded by former U.S. Vice President Al Gore and released Friday at the United Nations climate talks in Baku, Azerbaijan. Nations at the talks are trying to set new targets to cut such emissions.
