Carbon dioxide has an effect on the atmosphere and it has an effect for the first 50 parts per million and once it's done its job then it's finished and you can double it and quadruple it and it has no effect because we've seen that in the geological past, and we've seen it in times gone by when the carbon dioxide content was 100 times the current content. We didn't have runaway global warming, we actually had glaciation, so there's immediately a disconnect. So carbon dioxide is absolutely vital for living on earth; it's plant food, all of life lives off carbon dioxide. To demonise it shows that you don't understand school child science. —Ian Plimer, interviewed on ABNNewswire, June 2009