This article includes spaceflight as a major luxury. Leftist thinking here "if only humanity would give up luxuries like space flight, transportation, and central heating". Sure private jets are an issue, but the problem isn't luxuries like communists would frame it, the problem is Russia and China producing energy and materials the way we did in the 1940s, and pushing their pollution into us. We have the technology to mine and drill and burn coal in much cleaner ways. If Russia and China did it too, there would be such drastically lowered pollution we could all enjoy any luxury we wanted. That's progress.