A recent change to the Doomsday Clock has loaned a new sense of urgency to the fight against catastrophic man-made planetary climate change.

“We used to measure the likelihood of a man-made global catastrophe in hours, but that didn’t communicate much urgency,” said Arthur Clark of the Bulletin of the Atomic Scientists, which maintains the clock.

The Clock was changed to minutes when President Reagan almost plunged the world into a nuclear winter in the 1980s, and then to seconds when Greta Thunberg arrived on the scene in August 2018.

“We though about changing to milliseconds,” Clark said, “but who would pay attention if we said ‘you have 120,000 milliseconds before humanity destroys the planet’?”

After the most recent update, the clock will always say there are zero light years until global catastrophe occurs.