It is possible that a scientific discovery will be made that humans will later regret because it has awful consequences. The problem is, we probably would not know in advance and, once the discovery is made, it cannot be undiscovered.
Many of our problems are home-grown. Gordon Brown regularly advised the rest of the world to follow his British model of growth. But the model was flawed. It led to the highest level of household debt in relation to income in the world.