Business leader Richard Branson is to invest $3 billion to fight global warming.
He is pledging all profits from Virgin Atlantic and Virgin Trains over the next ten years to the effort.
The funds will be invested in schemes to develop renewable energy technologies.
The British entrepreneur added he hoped the move would encourage others to 'do what they can'.
The announcement was warmly welcomed by politicians and environmentalists, although some campaigners said that more needed to be done to curb the damage caused by the aviation industry - in which Virgin is a major player.
Mr Branson made the announcement in New York on the second day of the Clinton Global Initiative, an annual conference of business and political leaders hosted by former President Bill Clinton.
He said: 'What we've decided to do is to put any dividends, any profits, any shares, sales from those businesses, into tackling environmental issues.'
Mr Branson said that for this generation to hand over a near-pristine world to its children 'we must rapidly wean ourselves off our dependence on coal and fossil fuels'.
The first deal will see him backing California-based Cilion which was formed in June and which will make bioethanol from corn.