Lawrence M. Krauss in Bulletin of the Atomic Scientists:
As chair of the Board of Sponsors—a group initiated soon after Robert Oppenheimer and Albert Einstein helped form the Bulletin of the Atomic Scientists in 1945—I was humbled to speak at the publication's 70thanniversary dinner, where supporters once again convened, following a symposium, to explore the greatest existential challenges facing the world today.
I was tempted to begin my talk by saying happy birthday, but of course the birth of the Bulletin was not a joyous moment; rather, it was a somber one. Founded as it was by Manhattan Project scientists who “could not remain aloof to the consequences of their work,” the Bulletin had an immediate, urgent purpose, but it would be preferable to live in a world in which the Bulletin was not necessary. As pressing as the need seemed in 1945 to alert the public to the dangers of nuclear war and to stem the growth of nuclear arsenals, however, theBulletin is more necessary today than perhaps at any other time in its 70 year history.
With the development of nuclear weapons, humanity crossed a threshold: For the first time, the human race had the power to almost instantaneously and globally change the conditions for all life on our planet, and alter the environment in ways that could lead, if not to the extinction of our species, to the end of civilization as we know it.
Seventy years after the Nuclear Age began, the 21st century has brought a host of new global challenges for humanity to face.
More here.