Carbon footprints of North American cities. Map based on satellite data of carbon dioxide (CO2) emissions from cities in North America. This image combines data from the Global Human Settlement Layer (GHSL) with observations with the Operational Land Imager (OLI) on the Landsat 8 satellite. The CO2 levels are colour-coded from black and purple (low) through pink, red, orange and yellow to white (high). Major US cities shown here include Los Angeles, Chicago and New York. This map uses data from 2013.