Agence France-Presse: Australians have overtaken Americans as the world’s biggest individual producers of carbon dioxide, which is blamed for global warming, a risk consultancy says. British firm Maplecroft placed Australia’s per capita output at 20.58 tons a year, some four percent higher than the United States and top of a list of 185 countries. Canada, the Netherlands and Saudi Arabia rounded out the top five. China remains the world’s biggest overall greenhouse gas polluter, followed by the …