The C40 Climate Leadership Group is a voluntary consultative body organized by megacities of the world to address the grim implications of climate change on global communities. To confront the reality that megacities, which occupy only 2 percent of Earth’s total area, emit over 80 percent of total greenhouse gas emissions, the group was launched in London to address the problem based on a proposal by former London mayor Ken Livingstone in 2005. Seoul joined the Group in July 2006.