After all, climate change is an existential threat in a way local pollution isn’t, and the installation of the Trump team in power may mean that we have lost our last, best chance for a cooperative international effort to contain that threat.

Everyone who contributed to this outcome — very much, if I may say, including the journalists who elevated the fundamentally trivial issue of Hillary Clinton’s emails into the dominant theme of campaign reporting — bears part of the responsibility for what may end up being a civilization-ending event. No, that’s not hyperbole.

But climate change is a slow-building, largely invisible threat, hard to explain or demonstrate to the general public — which is one reason lavishly funded climate deniers have been so successful at obfuscating the issue. So it’s worth pointing out that most environmental regulation involves much more obvious, immediate, sometimes deadly threats. And much of that regulation may well be headed for oblivion.

Think about what America was like in 1970, the year the E.P.A. was founded. It was still an industrial nation, with roughly a quarter of the work force employed in manufacturing, often at relatively high wages, in large part because of a still-strong union movement. (Funny how Trumpist pledges to bring back the good old days never mention that part.)

It was also, however, a very polluted country. Choking smog was quite common in major cities; in the Los Angeles area, extreme pollution alerts, sometimes accompanied by warnings that even healthy adults should stay indoors and move as little as possible, were fairly common.