State-controlled Eni announced a new business plan on the day of a worldwide student protest against climate change, saying it would grow its green business and invest in planting forests to capture more than 20 million tonnes of CO2 by 2030.
It said it aimed to install more than 10 gigawatts (GW) of renewable capacity by 2030 from 0.2 GW this year.
"We are at the crossroads of a major transformation. Tackling (carbon reduction) will be a strategic priority of our board," Eni CEO Claudio Descalzi told analysts.
As Eni presented its plan in Milan on Friday thousands of school students in the Italian city joined a worldwide march calling for action against climate change.
The oil and gas industry has come under growing shareholder pressure to tackle carbon emissions following the 2015 Paris climate agreement seeking to reduce net emissions to zero by the end of the century, mostly by lowering fossil fuel burning.
BP and Total have set short-term targets on reducing carbon dioxide emissions. On Thursday Royal Dutch Shell said it planned to reduce carbon emissions from its operations and product sales by 2 percent to 3 percent in 2016-2021.
Eni's target does not include fuels and products it sells to customers but Descalzi said it was just a first step.
Eni, the biggest foreign oil and gas producer in Africa, also said it would be investing 1.4 billion euros over the next four years in renewable energy projects, mainly solar.
Companies like Shell and BP have accelerated spending on wind and solar power as they seek a bigger role in global efforts to slash carbon emissions and battle global warming.
Eni announced a four-year buyback programme with an initial allocation of 400 million euros this year and a 3.6 percent rise in its dividend to 0.86 euros in 2019.
The buyback will rise to 800 million euros (683.3 million pounds) if Brent goes above $65 a barrel.
"We will generate some 22 billion euros free cash over the plan in our upstream business, almost double our dividend need," CEO Descalzi said.
Over the last year the world's top oil and gas companies have come under pressure to return more cash to shareholders as profits and oil prices rise after a three-year crunch.
Oil and gas output will grow an average of 3.5 percent per year to 2025, Eni said, adding it expected 2.5 billion barrels of oil equivalent of new resources.
At 1306 GMT Eni shares were up 0.44 percent in line with Europe's oil and gas index.
(Reporting by Giancarlo Navach and Stephen Jewkes, editing by David Evans)
By Stephen Jewkes and Giancarlo Navach