That represents 4.7 percent to 5.3 percent of global carbon dioxide emissions during that time, the group said in a report.

The 120-year period in question starts in 1882, the year Exxon Mobil's ultimate predecessor, the Standard Oil Trust, was formed,

The Boston-based Coalition for Environmentally Responsible Economies, which has helped organize shareholder resolutions aimed at changing Exxon Mobil's environmental practices, helped commission the report, titled "Exxon's Climate Footprint."

The report said Exxon has been active in undermining climate science and policy making for years, in particular in lobbying against the Kyoto Protocol, the main international agreement to tackle climate change.

Exxon said the allegations by the environmental groups were without merit.

"We've been extremely open with our shareholders and the public on our position on and our tangible actions to address climate change," Exxon Mobil spokeswoman Lauren Kerr said.

She said Exxon has made its refineries and chemical plants 37 percent more efficient, which over the last 20 years has resulted in a reduction of carbon emissions of more than 200 million metric tons.

Energy companies produce substantial amounts of greenhouse gases, such as carbon dioxide, that scientists say cause climate change.

Insurance companies such as Munich Re say greenhouse risks, such as rising seas in low-lying nations and agricultural losses from global warming, could total hundreds of billions of dollars in the next 50 years.

Shareholders of Exxon Mobil, one of the world's biggest oil and gas companies, have filed three resolutions related to global warming this year, and for the first time the principal filers have been three public pension funds in New York City, Connecticut and Maine.

Exxon has also provided funds to Stanford University's Global Climate and Energy Project and has collaborated with the U.S. Energy Department's hydrogen fuel cell "Freedom Car" project, Kerr said.

Last year, Exxon shareholders rejected a renewable energy measure with 79 percent opposed, compared with 80 percent opposed a year earlier.

After shareholders voted down last year's resolution, Chief Executive and Chairman Lee Raymond said," We don't invest to make social statements at the expense of shareholder return."