ZeroHedge: Sweeney is exposing virtue-signaling elites who preach about climate change but fly around the world in their private jets (some of which are blocked from public view on FlightAware and FlightRadar24). According to a study published last year in the peer-reviewed journal Global Environmental Change, private jets in 2016 produced about 33.7 million metric tons of carbon dioxide. That's about 4% of total aviation emissions, equating to as much as the entire nation of Denmark emits per year.