Climate change by 90 companies

Scientific American has a brief article on climate-change deniers. I guess it's linked to the 20th anniversary of the Intergovernmental Panel on Climate Change's report which linked human activity to climate change for the first time. The article refers to a report by the Union of Concerned Scientists which claims that about 63 percent of all industrial emissions since 1854 have come from just 90 entities - 83 producers of coal, oil, and natural gas, and seven cement manufacturers. Here's a chart of the top 20.