Thirty-two energy companies led by Russia's Gazprom account for almost a third of all man-made greenhouse gas emissions if the burning of all the coal, oil and gas they produce is taken into account, a study said on Wednesday.
Total emissions linked to the companies rose 1.3 percent from 2010-13, despite efforts for curbs, according to the report by information provider Thomson Reuters and BSD Consulting, a global sustainability consultancy.
Emissions from the use of a company's products are usually excluded from corporate carbon accounts, based on emissions during operations, because they are outside firms' control.
Including final use of fossil fuels, Gazprom was the single biggest emitter, producing 1.26 billion tonnes of greenhouse gases in 2013, roughly equivalent to Japan's annual emissions.
Coal India followed on 820 million tonnes, ahead of Glencore, Petrochina, Rosneft, Royal Dutch Shell and Exxon Mobil, it said. The energy companies were picked from a list of 500 of the world's biggest firms by capitalization.
Overall, emissions by the 32 firms, including the final burning of coal, gas and oil, accounted for 11.7 billion tonnes of greenhouse gases, equivalent to 31 percent of the global total in 2013, it said.
"The footprint is staggering ... the overall purpose of this report is to create transparency" about sources of emissions, co-author Tim Nixon, managing editor of sustainability at Thomson Reuters, said by telephone.
"This is not a naming and shaming exercise," Nixon and co-author John Moorhead, executive manager of BSD Consulting, wrote in the report. "These are all companies that provide vital energy services to the global economy."
"They are also the companies that can provide the leadership for the next generation of low-carbon energy and or respond to the leadership from competitors, regulators or consumers," they wrote.
Businesses are meeting in Paris this week to try to chart ways to respond to global warming before a summit in the French capital in December that is due to agree a global deal to restrict emissions of greenhouse gases.
