OTTAWA -- He changed my life.

That phrase came up repeatedly Wednesday as movers and shakers from around the globe paid tribute to Maurice Strong, a high school dropout who became a multi-millionaire businessman, public servant, United Nations fixture and internationally renowned champion of the environment.

Strong died last November at the age of 86.

Prime Minister Justin Trudeau, whose late father picked Strong to be the founding head of Petro-Canada back in the 1970s, called him "a truly great citizen of Canada and citizen of the world" who has left behind an incredible legacy as "a brilliant businessman, devoted environmentalist, an inspirational philanthropist."

Former prime minister Paul Martin recalled how Strong gave him his first job and was one of those who said Strong "changed my life."

"In fact, he bettered the lives of most people that he knew."

Among those who spoke at the celebration of Strong's life were former World Bank president James Wolfensohn, former Governor General Adrienne Clarkson and her husband, author John Ralston Saul, and Achim Steiner, under-secretary general of the United Nations -- a position Strong himself held for many years.

Glowing written tributes were sent by former Soviet Union president Mikhail Gorbachev, former Norwegian prime minister Gro Harlem Bruntland and former UN secretary-general Kofi Annan, who called Strong the "father of the world environmental movement."

Strong headed the first UN conference on the environment in Stockholm in 1972, set up the UN's environment program, and led the Earth summit in Rio de Janeiro in 1992 -- precursor to the Kyoto, Copenhagen and Paris accords on climate change.

He also led UN famine relief efforts in Africa.

"He changed the world," said Ralston Saul.