Speaking on the sidelines of the U.N. World Oceans Day conference in New York, the Virgin Group founder said Trump failed to recognize that renewable energy sources were cheaper than oil and coal and will produce "massively more jobs" than fossil fuels, the Associated Press reports.
"We wanted the United States of America to not talk selfishly but to talk about being part of this world which doesn't have walls, and help us get out there and save it," Branson reportedly said.
In an interview with AP, Branson said that he and Trump had something in common: they are both grandfathers. Were he to meet the U.S. President, Branson said this would be his message: "History will be kind to us if we do something for our grandchildren, and history will not forgive us if we neglect our grandchildren."
For more on Richard Branson, watch Fortune's video:
It wasn't the first time the high-profile philanthropist, climate activist and friend of the Obamas had harsh words for Trump. In the lead-up to last year's presidential election, Branson described him as "consumed by petty personal quarrels" and "wrapped up in himself rather than concerned with global issues."