That was my first question after I learned about GRB. According to wikipedia you linked, atmosphere might be sufficient to protect from gamma rays, unfortunatel

That was my first question after I learned about GRB. According to wikipedia you linked, atmosphere might be sufficient to protect from gamma rays, unfortunately at a very high cost to stratosphere. "The greatest danger is believed to come from Wolf–Rayet stars, regarded by astronomers as likely GRB candidates. When such stars transition to supernovae, they may emit intense beams of gamma rays, and if Earth were to lie in the beam zone, devastating effects may occur. Gamma rays would not penetrate Earth's atmosphere to impact the surface directly, but they would chemically damage the stratosphere."