In 1816, the Northern Hemisphere experienced what historians call the year without a summer. A series of volcanic eruptions had injected enough material into the atmosphere to suppress temperatures across the globe. Crops failed on a massive scale. Malnutrition spread, famine followed, and disease took hold in weakened populations. This wasn't just a bad harvest, it was a cascading subsistence crisis that reached across continents. China felt it. The Southern Hemisphere felt it. But the Northern Hemisphere bore the worst of it.
This event has been called the last great subsistence crisis of western civilization. It's a reminder that climate doesn't need to shift permanently to cause catastrophic disruption. A single year of suppressed sunlight and cooler temperatures was enough to destabilize food systems and trigger a humanitarian disaster. The question worth asking: if volcanic forcing alone could do that in 1816, what does that tell us about the fragility of our current systems and the broader range of natural forcing mechanisms we should be accounting for?