Climate change will be considered a joke in five years time, meteorologist Augie Auer told the annual meeting of Mid Canterbury Federated Farmers in Ashburton this week.
Man's contribution to the greenhouse gases was so small we couldn't change the climate if we tried, he maintained.
"We're all going to survive this. It's all going to be a joke in five years," he said.
A combination of misinterpreted and misguided science, media hype, and political spin had created the current hysteria and it was time to put a stop to it.
"It is time to attack the myth of global warming," he said.
Water vapour was responsible for 95 per cent of the greenhouse effect, an effect which was vital to keep the world warm, he explained.
"If we didn't have the greenhouse effect the planet would be at minus 18 deg C but because we do have the greenhouse effect it is plus 15 deg C, all the time."
The other greenhouse gases: carbon dioxide, methane, nitrogen dioxide, and various others including CFCs, contributed only five per cent of the effect, carbon dioxide being by far the greatest contributor at 3.6 per cent.
However, carbon dioxide as a result of man's activities was only 3.2 per cent of that, hence only 0.12 per cent of the greenhouse gases in total. Human-related methane, nitrogen dioxide and CFCs etc made similarly minuscule contributions to the effect: 0.066, 0.047 and 0.046 per cent respectively.
"That ought to be the end of the argument, there and then," he said.
"We couldn't do it (change the climate) even if we wanted to because water vapour dominates."
Yet the Greens continued to use phrases such as "The planet is groaning under the weight of CO2" and Government policies were about to hit industries such as farming, he warned.
"The Greens are really going to go after you because you put out 49 per cent of the countries emissions. Does anybody ask 49 per cent of what? Does anybody know how small that number is?
"It's become a witch-hunt; a Salem witch-hunt," he said.