Whatever the merits of the suit, Mr. de Blasio and his predecessor, Michael R. Bloomberg, are the very embodiment of a possible line of defense by the oil companies. Namely, that it wasn’t the oil companies that created the greenhouse gases, but society in general — companies and individuals who used oil to generate electricity, or for transportation.

Many mornings, Mr. De Blasio is driven 11 miles to his gym in Park Slope, Brooklyn, from the official mayor’s residence on the Upper East Side of Manhattan, Gracie Mansion.

Former Mayor Bloomberg, a billionaire, rode the subway most days. On the other hand, Mr. Bloomberg routinely splurged on carbon usage by deploying his personal fleet of carbon-inefficient private jets and helicopters for long-distance travel. He would use them to fly to a weekend home in Bermuda, for instance, or to Europe. In an episode so rich you could choke on it, Mr. Bloomberg brought an entourage aboard his personal Falcon 900 to Copenhagen, at a cost in carbon emissions that was 37 times more than if the group had flown commercial.

The reason for the trip? Mr. Bloomberg was speaking at a conference on climate change.

In New York, the police regard S.U.V.s as the most prudent for moving and protecting the mayor, and no one should begrudge any officials the security they need to carry out the work they do on behalf of the public. That goes for their recreation, at least for mayors, who put in long hours. At some point, every last one of them winds up splutteringly frayed or fried, so getting to a favorite gym probably helps keep Mr. de Blasio from losing his mind.

Just because it is easier to deplore hypocrisy in others than in ourselves does not make any of us immune to it. Hypocrisy is more widely practiced by humans than any creed. Mr. Bloomberg’s health department wanted restaurants to cut sodium from their recipes but he was known to shake salt on slices of pizza and saltine crackers.