"Options such as wind and biomass have all been proven, while other methods such as Ocean Thermal Energy Conservation (OTEC) - for which Trincomalee harbour (in eastern Sri Lanka) is well suited - are less widely known and tested," he said.

It is interesting that Clarke did not mention nuclear energy. He did not give it as an option even for Sri Lanka, which is energy starved acutely. Perhaps in his view, nuclear energy was too costly and fraught with dangers.

Known as the father of satellite communication, which he predicted in 1945, Clarke believed in communication facilities being made available to all, but he believed communication alone would not solve the world's problems.

He said the North Ireland problem would have been solved long ago, if improved communication was the panacea. The problem lingered because of a lack of political communication, a meeting of minds, he pointed out.

On the conflict in Sri Lanka, his adopted home since the 1950s, Clarke said: "The biggest challenge for all Sri Lankans in the coming century (2000s) would be achieving better communication and understanding among the different ethnic, religious and cultural groups and sub-groups all of whom call this their mother land. For material progress and economic growth would come to nothing if we allow the primitive forces of territoriality and aggression to rule our minds."