Science

Doctors from the "Nobel Laureate Assembly for the Prevention of Nuclear War" are absolutely more qualified to report on the risks of nuclear war than a randomly picked person off the street.

He was clear that his estimation is "crude" and "not rigorous"; nuclear holocaust is uncharted territory and noone could truly be considered an expert. I think the average person wildly underestimates how close we are to mutually assured destruction. There's a natural human tendency towards optimism bias, but it's probably more likely we kill ourselves off as a species (ie "great filter" solution to the fermi paradox).