How to save us from climate-change doomsayers

And the industrial company DuPont denounced the ozone-depletion theory as "a science-fiction tale . . . a load of rubbish . . .utter nonsense".

Both theories were initially rejected by scientists as well: not enough evidence; need to be cautious; bans on DDT or CFCs would destroy the economy; too many good things were being done with DDT and CFCs that their role was essential to society; action should be delayed until we know more; it is not the job of the scientist to advocate policy; it is for politicians to act on the science etc etc.

In both cases, the authors of the theories were not quintessential scientists – cautious plodders slowly gathering evidence and publishing bit by bit in peer-reviewed journals. Rather they committed two cardinal sins in the scientific community. They took their science directly to the public and they became advocates for a policy response to their findings.

They urged a ban on DDT before spring became silent and devoid of birdsong, and a ban on CFCs before the ozone got so depleted that the rise in the number of skin cancers would make outdoor life impossible and disrupt the plant-animal food chain.

Nonetheless, in those days governments were more courageous and science was more respected. Moreover, the two theories were more testable and explicable to the masses than climate change. After all, the weather is always variable.

But the hole in the ozone lawyer over the Antarctic was measurable. And the simple chemistry was explicable and frightening. CFC molecules rising to the upper atmosphere could latch on to ozone molecules (molecules with three oxygen atoms) and combine with one of those atoms leaving the other two as ordinary oxygen. Moreover, the reaction would result in yet another loose chlorine atom, which would be available to react with yet another ozone molecule causing a catalytic chain reaction lasting up to two years for each rising CFC molecule before the chlorine sank.

The reactions could be repeated in the laboratory.

CFCs were banned throughout the world when the Montreal Protocol came into force in 1989. Fifteen years were wasted by the sceptics and deniers and the ozone layer will not be restored until 2050 -- but doom was averted.

Doom was averted not because of some sort of natural correction, or hope, or whingeing and hand-wringing about the economy, but because two scientists were gutsy enough to stand up to industry and to science-funding sources and go public – so there were no excuses for inaction.

It was similar with Silent Spring. DDT was banned, or at least heavily restricted and doom was averted.

Those who say human ingenuity will deal with climate change so there is no need to do anything about it are quite wrong and self-contradictory.

Human ingenuity will only deal with climate change if we act in the way we did when warned about DDT and CFCs. We acted and acted vigorously. That's how you deal with climate-change doomsayers.