The American climate activists who have flocked to the 2015 United Nations Climate Change Conference in Paris this week tend to have one thing in common: many own the “it” car for their tribe, the VW Jetta Wagon TDI. At 49 MPG, the Jetta does better than many hybrids, and drives German, too. Car and Driver magazine celebrated it as a “green” car that even an auto enthusiast could love. That led to its cult status among greenies; for years it was hard to find one even in the want ads.