There are extremists who claimed the ocean would be destroyed by acid rain, oil would run out by 2020 and co2 levels would push the temps to 25+C in the UK for most of the year.
None of these things have happened but these people were still let near schools unvetted with these claims in the 90s. If day we've learned to communicate science better but fools in the know all to quickly become political bedfellows with money with agendas attached to it...