Thread by @ErrataRob

The most perfect pair of tweets today. The sort of tweets I wish I'd made. #jealous

I can't tell if @MattWalshBlog is serious, but anyway, data.

The Montreal Protocol treaty started in 1989 where governments (including US) phased out the CFCs that were damaging the ozone, causing their use to plummet. The ozone hole has been slowly shrinking as a result.

They remain in the atmosphere for a long time, so the steady shrinking can take another century.

Had we not taken action in the 1980s, things would be catastrophic now.

As for acid rain, it's caused mostly by sulfur dioxide and nitrogen oxides. The Clean Air Act of 1963 and SO₂ regulations in 1971 have steadily cleaned the atmosphere of SO₂, like adding scrubbers to coal plants (aka. "clean coal").

Nitrogen oxides have been cleaned primarily with the catalytic converter in your car. You know how you need regular emissions checks? That's one of the government regulations that has largely eliminated acid rain in the United States.

We used to talk about smog in cities. That's also been disappearing because of emissions controls in cars. Because government regulation.

I'm wholly in agreement that the EPA overstepped its authority trying to regulate CO₂, and that it needs an act of Congress to make CO₂ regulations. But it's clear that the EPA and Clean Air Act have done a tremendous amount to clean our air.