Fewer than expected Canberrans turned out yesterday for a rally calling for a shift to renewable energy sources.

The centrepiece of the rally was a sign spelling out the words "clean energy for eternity", formed by groups of people standing in formation.

But the shortage of protesters meant organisers had to use ingenuity to make their message clear.

Nevertheless, helicopters and planes could clearly make out the words from the sky, although a large map of Australia forming part of the sign had to be abandoned, due to the lack of Australians to form it.

About 1000 people attended the event, compared with 3000 who turned up for a similar stunt at Tathra on the NSW South Coast in May.

Event organiser, Bega orthopaedic surgeon Matthew Nott, said the idea was to get individuals to think about conserving energy, and communities to work out solutions for the climate change problem.

Dr Nott said his environmental passion came alive on New Year's Day this year when he was on surf lifesaving patrol at Tathra.

"On that particular day, a hot westerly wind came through which heated the beach up to 42 degrees Celsius, which was the hottest temperature ever recorded at Tathra beach by 4 degrees," he said.

At the same time, Dr Nott was reading a book on climate change and it struck a chord.

"I had a decision to make at that stage, whether I dig a little hole in the sand and put my head in it, or keep reading," he said.

"I kept reading and, ever since then, I have been really devoting as much energy as I can to raising awareness about climate change and also finding real solutions."

Dr Nott believed climate change was no longer just an environmental issue.

"This is about sustainability and anyone with kids should be really fired up about climate change because I think we only have a limited amount of time to make a significant difference."

Dr Nott is planning similar rallies at 25 locations across Australia. The next most likely will be at a Sydney beach.