An anonymous reader quotes a report from The Guardian: Just 100 companies have been the source of more than 70% of the world's greenhouse gas emissions since 1988, according to a new report. The Carbon Majors Report (pdf) "pinpoints how a relatively small set of fossil fuel producers may hold the key to systemic change on carbon emissions," says Pedro Faria, technical director at environmental non-profit CDP, which published the report in collaboration with the Climate Accountability Institute. The report found that more than half of global industrial emissions since 1988 -- the year the Intergovernmental Panel on Climate Change was established -- can be traced to just 25 corporate and state-owned entities. The scale of historical emissions associated with these fossil fuel producers is large enough to have contributed significantly to climate change, according to the report. ExxonMobil, Shell, BP and Chevron are identified as among the highest emitting investor-owned companies since 1988. If fossil fuels continue to be extracted at the same rate over the next 28 years as they were between 1988 and 2017, says the report, global average temperatures would be on course to rise by 4C by the end of the century. This is likely to have catastrophic consequences including substantial species extinction and global food scarcity risks.