Scientists have criticised the credibility of the documentary The Great Global Warming Swindle that aired on ABC TV last night.

The documentary argued solar activity is the cause of current environmental problems, not the human creation of carbon dioxide.

Critics say the documentary damages the credibility of science because no scientist can make definitive claims about what will happen in the future.

American scientist Carl Wunsch say the climate change debate is very complex and this documentary confuses the facts.

"Anybody who tells you they know what is going to happen 20 years from now, 100 years from now, is not a good scientist," he said.

"The science can only say, at this stage, that there are certain possibilities that we are aware of."

But the program's supporters believe it is an answer to the popular award-winning documentary An Inconvenient Truth, made by former US vice-president Al Gore.