7. Bias connected with the fact that global catastrophe is by definition a unique event
Global doom sounds fantastic. It has never happened before. If it does happen, it can only happen once. Therefore normal inductive processes of sampling are ineffective to predict it. If something is true at t=1, t=2, t=3, and so on, we can reasonably assume it will be true at t+1 (or all t). This methodology is useful during smooth conditions, but ineffective for predicting abrupt, extreme phenomena without precedent. A separate issue is that a lethal effect that kills off or disables humanity a little bit at a time may never appear to be a global catastrophe at first, but leads to human extinction when operating over a sufficient duration of time.