Why don't we talk about acid rain and the ozone hole anymore? Scientists debunk misinformation

If you're over 30, you likely remember a time when there was a lot of hand-wringing and furrowed brows over the ozone hole and skin cancer, as well as the threat of acid rain destroying ecosystems.

In the 1980s and '90s, those global environmental crises created buzz and grabbed headlines, but in the decades that followed, the world turned its attention to another threat: climate change.

Yet the success stories of how those threats were tackled — through the co-operation of scientists, policy-makers and the public — are often overlooked, if not outright denied.

A barrage of misinformation on social media, including various tweets and videos, claims those issues were never real in the first place. It's a conspiracy theory that takes on various shapes, but the underlying common thread is the false claim that climate change is just the latest in a series of hoaxes invented by governments to control the public.

One TikTok video (reminder: this is misinformation) with more than three million views dismisses several global threats as "politics," listing off a series of examples: "In the '80s, it was acid rain will destroy all the crops in 10 yrs; in the '90s it was the ozone layer will be destroyed in 10 years; in the 2000s it was the glaciers will all melt in 10 years ...," the TikTok poster says.

The video claims it was all "fear-mongering nonsense" that never came true.

Watching the video during an interview with CBC News, atmospheric chemist Susan Solomon nods knowingly. It's not the first time she's confronted that attitude.

"I've heard that kind of — I don't want to even call it a line of argument — I've heard that kind of assertion in the past," said Solomon, who is a professor in the department of Earth, atmospheric and planetary sciences at the Massachusetts Institute of Technology.

"It's a little bit like saying, 'I had a heart attack and my doctor put a stent in. They told me I had to exercise and now I feel great. So I think that was all just nonsense to make money for the medical establishment."

It was Solomon's research in the 1980s that helped establish the cause of the thinning ozone: refrigerants called chlorofluorocarbons, or CFCs.

She recalls a particular meeting where colleagues were discussing ozone depletion. Solomon, 30 at the time, said she presented her paper identifying how refrigerants were breaking apart in the stratosphere.

"People just laughed," she said.

But Solomon knew she was on to something, and her work contributed to the growing body of evidence that ultimately led to the signing of the Montreal Protocol in 1987, phasing out the harmful refrigerants.

That treaty is working, according to a recent international report, which said the ozone is expected to recover by 2066.