Sydney-based writer and futurist Richard Watson warned an eco-tourism and green travel conference in Adelaide today that there was a dark side to tourism.

"In the short term there is a definite problem that people are possibly going to destroy the very thing they came to experience.

"That is without a shadow of a doubt true depending on what the economy does and there is going to be a very, very significant growth in population numbers over the next 10, 20, 50 years."

However, Mr Watson said in the long-term oil prices could hurt tourism badly.

"When oil starts hitting $200 and $300 a barrel - and it's not if it's going to hit, it will hit eventually - that is going to fundamentally change all this.

"The price of oil is an extremely important part of the tourism industry."

He said about one quarter of all money spent on travel in Australia came from overseas visitors - that figure would drop as new competing destinations emerged.

Ecotourism Australia chairman Alastair McCracken said the growing awareness of climate change provided a significant chance for the industry to focus on a sustainable future.

"Australia's tourism industry faces the most significant threats ever dealt to such a major industry," he said.

The four day conference has incorporated the first annual EcoTravel awards, which will be announced on Tuesday night, as well as the launch of a world-first climate action certification pilot program to acknowledge tourism operators who reduce their carbon footprint.