Only 100 energy companies have accounted for more than 71 percent of all global greenhouse gas emissions since 1988, researchers reported on Monday.

According to a study from the British research firm Carbon Disclosure Project (CDP) and the Climate Accountability Institute, major fuel firms operating around the globe have produced nearly three-fourths of all the greenhouse gas emissions since climate change was officially recognized by the United Nations.

Twenty-five of those firms alone produced more than half the greenhouse gas emissions, the study said. The highest emitters include investor-owned companies such as ExxonMobil, Shell, BP and others, and state-owned companies like Saudi Aramco, Gazprom and coal producers in China.

ADVERTISEMENT

Catalogs of greenhouse gas emissions are generally collected and presented on a nation-by-nation basis, but CDP’s report aims to assign emissions to industrial fossil fuel firms specifically.

The majority of climate change researchers have concluded that the Earth is warming due to human activity, primarily the release of greenhouse gas emissions from burning fossil fuels.

The report "offers insight into responsibility from the perspective of the producers of hydrocarbons,” Pedro Faria, CDP’s technical director, wrote in a forward to the study.

“Those companies that have made astonishing returns over decades through the extraction and production of greenhouse gas emitting products.”

The study says the companies would need to begin reducing their collective emissions by 2025 in order to help the world meet the 2 degree Celsius warming target most scientists say is necessary for avoiding the worst of climate change.

“Fossil fuel companies can contribute to the transition by reducing operational emissions, shifting to lighter fossil fuels, engaging in the deployment of [carbon capture technology] and other carbon-offset options and diversifying their portfolio of primary energy products to encompass renewables,” the study said.