Gerry Stanhill, an English scientist working in Israel, notices something odd while comparing sunlight records: readings from the 1950s show 22% more solar radiation reaching the ground than current measurements do. He starts pulling data from other countries and finds the same pattern almost everywhere, a decline researchers come to call global dimming. The fall is uneven, roughly 10% over the United States, nearly 30% in parts of the former Soviet Union, 16% across the British Isles, averaging out to a 1-2% drop per decade worldwide between the 1950s and 1990s. Scientists interviewed here trace the cause to particles from industrial pollution and aircraft contrails scattering sunlight before it hits the surface, and they lay out the uncomfortable twist: less sunlight may have been masking the true scale of greenhouse warming all along, meaning cleaning up the air could unmask a much sharper temperature rise. The episode builds its case from five decades of measurement records rather than speculation.