Glenn Reynolds says they should practice what they preach, by government force if necessary:

First, we need to tax the “blue zones.” That is, we need to impose steep taxes on property in coastal areas that will be flooded by the sea-level increases that global warming is supposed to bring. By discouraging people from living or building there now, we’ll save ourselves from big problems in the future. Sure it’ll drive down property values, but those values should go down — they’re values for property that’s going to be flooded anyway, remember?

Second, we need to ban taxpayer-funded air travel to conferences. State legislatures could ban reimbursement for travel outside their states; Congress could require that no federal grant money be spent on air travel to conferences and similar events. A lot of academic conferences would fail, but that’s a small price to pay for saving the planet. And besides, it will encourage the development of Internet-based conference alternatives. A whole new industry might result: Green jobs!

Donald Trump can strengthen America by dumping Paris agreement: Sen. Inhofe
Third, we need to ban private jet travel. At first I thought about just taxing it heavily, but with the planet at stake, that might not be enough. It’s nice that John Travolta can have his own Boeing 707, or that Leonardo DiCaprio can jet around the world speaking against climate change, but the carbon emissions involved set a bad example that outweighs anything he might say. So no more private jets. Bigshots will just have to fly commercial like everyone else, the way they did in the 1950s. (And sorry, Leo, but massive yachts have to go, too). Politicians, too, should have to fly commercial. No more government-funded “executive jets” for them.

Fourth, we need a luxury tax on mansions. Any home more than twice the size of the average American home should be taxed at 25% of its value per year. Celebrities and the rich enjoy great powers of persuasion — but with great power comes great responsibility, and they have a great responsibility to set a good example for the rest of us on climate change!

As he says, it seems like a modest proposal.