Your great-great-great-grandparents’ cold world

Regardless of what our industrial society is doing to Earth's climate, nature can produce surprises of its own accord. Sketchy observations and recent inferences show that, from about 1550 to 1850, a good part of the planet was as much as 1.0°C/1.8°F cooler than today. That may not sound like much, but it was enough to profoundly affect society in Europe and North America, where the temperature drop from medieval times was felt most strongly. Famines dogged Europe, particularly in 1594-97 and in 1693, when perhaps one out of every three Finlanders died. Expanding glaciers swallowed up entire Swiss villages, and paintings of the era show people skating on canals that virtually never freeze over today. Sunspot records show the Sun was fairly inactive during the heart of the Little Ice Age, with incoming solar energy perhaps dipping by a quarter of a percent or so. It's possible, but difficult to prove, that this lowered solar energy was at least partly to blame for the cooldown. One factor that's well known is the sun-screening action of volcanoes, which were especially active in the 1700s and early 1800s. The epochal eruption of Indonesia's Таmbora on April 5,1815, is the most likely culprit for 1816's year without a summer. June snows and freezes plagued New England, and Europe was caught in relentless drear. Holed up with fellow writers in a summer house near Lake Geneva, teenager Mary Shelley penned a dark novel that reflected her mood: Frankenstein.