Science-fiction writer Arthur C. Clarke listed three wishes on his 90th birthday:

At 90, Sci-fi Guru Wishes that E.T. Would Call

Science-fiction writer Arthur C. Clarke listed three wishes on his 90th birthday: for the world to embrace cleaner energy resources, for a lasting peace in his adopted home, Sri Lanka, and for evidence of extraterrestrial beings.

"I have always believed that we are not alone in this universe," Clarke said in a speech to a small gathering of scientists, astronauts and government officials Sunday in Colombo where he lives.

Humans are waiting until extraterrestrial beings "call us or give us a sign," he said. "We have no way of guessing when this might happen. I hope sooner rather than later."

Clarke has written more than 100 sci-fi books, including "2001: A Space Odyssey." His fiction predicted space travel before rockets were even test-fired and envisioned computers dominating ordinary lives.

On a different note, and just a day after delegates at a U.N. conference in Indonesia agreed to a blueprint for fighting global warming by 2009, he urged the world to consider switching to environmentally friendly fuels.

"I would like to see us kicking our current addiction to oil and adopt clean energy resources," Clarke said.

The British-born author moved to Sri Lanka in 1954 and became a resident guest — meaning he can stay permanently without a resident visa — in 1975. Since then, an ethnic conflict has flared and continues to rage between government forces and Tamil Tiger separatists on the tropical island. More than 70,000 people have been killed in the fighting.

"I have been living in Sri Lanka for 50 years and half that time I have been a sad witness to the bitter conflict that divides my adopted country," Clarke said. "I dearly wish to see a lasting peace being established in Sri Lanka. Peace just cannot be wished, it requires a great deal of hard work, courage and persistence."

Clarke, who suffers from post-polio syndrome and is confined to a wheelchair, cut a cake with "Happy Birthday Sir Arthur" written on it, as Sri Lanka's President Mahinda Rajapakse, visiting astronauts and scientists sang "Happy Birthday." He was knighted in 1998.

Russian Alexei Leonov, who took the first walk in space in March 1965 and was a guest at Clarke's birthday tea party Sunday, gave him a medal from the Federation of Cosmonauts of Russia.

"Sometimes I am asked how I would like to be remembered," Clarke said. "I have had a diverse career as a writer, underwater explorer and space promoter. Of all these I would like to be remembered as a writer."