Kjell Inge Roekke, a former fisherman who made his fortune in the oil industry, will begin by funding a research ship that will remove plastic from the ocean.
It will operate in partnership with the environmental organisation WWF.
He joins other billionaire philanthropists including Bill Gates, Warren Buffet and Mark Zuckerberg.
Mr Roekke has an estimated wealth of $2bn (£1.6bn).
"I want to give back to society the bulk of what I've earned," he said in an interview with the Aftenposten newspaper. "This ship is a part of that."
