What If Every Volcano on Earth Erupted at the Same Time?

You are on a ferry crossing a bay on an ordinary afternoon when every phone on board buzzes at once. Behind the nearest hill a grey column is rising into the sky, and it is not the only one. In this story every volcano on Earth wakes up in the same hour. We follow what comes next, from the first hour to year three: the sound of the eruptions, the ash that grounds every aircraft, the jet that once lost all four engines above the sea, the sulfur veil that dims the Sun, the first summer frosts and a volcanic winter that empties the grain stores. Then the light slowly returns, and we look at the gifts of fire, the famous story born in a summer that never came, and the one thing volcanoes can never fix. Where is the nearest volcano to your home, and how far away is it? Tell us in the comments, and which country you are watching from. Next on Hour Zero: What if Earth's gravity doubled for a year? 0:00 The ferry and the grey column 1:19 Hour 1: the map lights up 2:53 Day 1: the ash 5:09 Day 1: grounded skies 6:54 Week 1: the sulfur veil 8:56 Month 1: the first frosts 10:36 Year 1: the volcanic winter 12:35 Year 3: the light returns 14:20 The gifts of fire 16:03 Could it really happen? 18:08 The real lesson Sources: USGS (active volcanoes; Volcanoes Can Affect Climate; Hawaiian Volcano Observatory on volcanic and human CO2; Mount Pinatubo Fact Sheet 113-97; Volcano Hazards Program; Yellowstone Volcano Observatory); Smithsonian Global Volcanism Program; Brown et al. 2015; Freire et al. 2019 (Frontiers in Earth Science); EUROCONTROL, ash cloud of April and May 2010; British Airways Flight 9 (1982) case summary; FAO Food Outlook and cereal stocks; NOAA Ocean Exploration; Burgess et al. 2017 (Nature Communications); Schoene et al. 2019 (Science); Oppenheimer 2003 (Tambora 1815); Thordarson and Self 2003 (Laki 1783); Parsons and Whitney 2012; Orkustofnun, Iceland. The scenario itself is a thought experiment: volcanoes cannot all erupt at once. Footage and photos: Wikimedia Commons, public domain and CC0 only (USGS, NOAA, NASA, U.S. National Park Service and other U.S. government sources; Commons contributors under CC0). AI disclosure: the narration is AI-assisted.