A person who has become famous for predicting apocalyptic, world-ending scenarios that never actually happen. This person continues to remain well-respected even after it has become obvious that none of their predictions will ever come true. An example would be Paul Erlich, author of "The Population Bomb" (1968), warning of mass starvation in the 1970's and 1980's due to overpopulation. Professor Erlich holds an endowed chair at Stanford University and has received countless awards in spite of the fact that his entire career has been based on complete bullshit. Other threats to our continued existence promoted by teflon prophets include global cooling, acid rain, dioxin, Y2K and currently, global warming- recently rebranded "global climate disruption" by President Obama's science czar John Holdren, who once co-authored a book with, wait for it, Paul Erlich!
Al Gore is a teflon prophet.